Multi-User Interference Cancellation Scheme(s) for Muliple Carrier Frequency Offset Compensation in Uplink OFDMA

DEFF Research Database (Denmark)

Nguyen, Huan Cong; Carvalho, Elisabeth De; Prasad, Ramjee

2006-01-01

(ICI) and degrade the system performance considerably. In this paper, we propose a novel Multi-User Interference (MUI) cancellation scheme for uplink OFDMA, which utilizes multiple OFDM-demodulators architecture to correct and then compensate the negative effects of multiple CFOs at the receiver's side......We consider the uplink of an Orthogonal Frequency Division Multiple Access (OFDMA)-based system, where each Mobile Station (MS) experiences a different Carrier Frequency Offset (CFO). Uncorrected CFO destroy the orthogonality among subcarriers, which could cause severe Inter-Carrier Interference...

Generalized location-based resource allocation for OFDMA cognitive radio systems

KAUST Repository

Ben Ghorbel, Mahdi

2010-09-01

Cognitive radio is one of the hot topics for emerging and future wireless communication. Cognitive users can share channels with primary users under the condition of non interference. In order to compute this interference, the cognitive system usually use the channel state information of the primary user which is often impractical to obtain. However, using location information, we can estimate this interference by pathloss computation. In this paper, we introduce a low-complexity resource allocation algorithm for orthogonal frequency division multiple access (OFDMA) based cognitive radio systems, which uses relative location information between primary and secondary users to estimate the interference. This algorithm considers interference with multiple primary users having different thresholds. The simulation results show the efficiency of the proposed algorithm by comparing it with an optimal exhaustive search method. © 2010 IEEE.

Contribution to Dynamic Spectrum Assignment in multicell OFDMA networks

OpenAIRE

Bernardo Alvarez, Francisco

2010-01-01

La próxima cuarta generación (4G) de redes de comunicaciones móviles celulares considera una interfaz radio basada en OFDMA (Orthogonal Frequency Division Multiple Access). Esta tecnología ofrece robustez a la propagación multicamino y diversidad en frecuencia gracias a la división del ancho de banda de operación en un conjunto de pequeños subcanales en frecuencia para así alcanzar un uso eficiente del espectro. Sin embargo, un importante desafío en una interfaz radio OFDMA es la manera en la...

Transmit Power Minimization and Base Station Planning for High-Speed Trains with Multiple Moving Relays in OFDMA Systems

KAUST Repository

Ghazzai, Hakim

2016-03-15

High-speed railway system equipped with moving relay stations placed on the middle of the ceiling of each train wagon is investigated. The users inside the train are served in two hops via the orthogonal frequency-division multiple access (OFDMA) technology. In this work, we first focus on minimizing the total downlink power consumption of the base station (BS) and the moving relays while respecting specific quality of service (QoS) constraints. We first derive the optimal resource allocation solution in terms of OFDMA subcarriers and power allocation using the dual decomposition method. Then, we propose an efficient algorithm based on the Hungarian method in order to find a suboptimal but low complexity solution. Moreover, we propose an OFDMA planning solution for high-speed train by finding the maximal inter-BS distance given the required user data rates in order to perform seamless handover. Our simulation results illustrate the performance of the proposed resource allocation schemes in the case of the 3GPP Long Term Evolution-Advanced (LTE-A) and compare them with previously developed algorithms as well as with the direct transmission scenario. Our results also highlight the significant planning gain obtained thanks to the use of multiple relays instead of the conventional single relay scenario.

IQ imbalance tolerable parallel-channel DMT transmission for coherent optical OFDMA access network

Science.gov (United States)

Jung, Sang-Min; Mun, Kyoung-Hak; Jung, Sun-Young; Han, Sang-Kook

2016-12-01

Phase diversity of coherent optical communication provides spectrally efficient higher-order modulation for optical communications. However, in-phase/quadrature (IQ) imbalance in coherent optical communication degrades transmission performance by introducing unwanted signal distortions. In a coherent optical orthogonal frequency division multiple access (OFDMA) passive optical network (PON), IQ imbalance-induced signal distortions degrade transmission performance by interferences of mirror subcarriers, inter-symbol interference (ISI), and inter-channel interference (ICI). We propose parallel-channel discrete multitone (DMT) transmission to mitigate transceiver IQ imbalance-induced signal distortions in coherent orthogonal frequency division multiplexing (OFDM) transmissions. We experimentally demonstrate the effectiveness of parallel-channel DMT transmission compared with that of OFDM transmission in the presence of IQ imbalance.

Energy-efficient power control for OFDMA cellular networks

KAUST Repository

Sboui, Lokman

2016-12-24

In this paper, we study the energy efficiency (EE) of orthogonal frequency-division multiple access (OFDMA) cellular networks. Our objective is to present a power allocation scheme that maximizes the EE of downlink communications. We propose a novel explicit expression of the optimal power allocation to each subcarrier. We also present the power control when the transmit power is limited by power budget constraint or/and minimal rate constraint and we highlight the occurrence of some transmission outage events depending on the constraints\\' parameters. In the numerical results, we show that our proposed power control improves the EE especially at high power budget regime and low minimal rate regime. In addition, we show that having a higher number of subcarriers enhances the OFDMA EE.

A generic interference model for uplink OFDMA networks with fractional frequency reuse

KAUST Repository

Tabassum, Hina

2014-03-01

Fractional frequency reuse (FFR) has emerged as a viable solution to coordinate and mitigate cochannel interference (CCI) in orthogonal frequency-division multiple-access (OFDMA)-based wireless cellular networks. The incurred CCI in cellular networks with FFR is highly uncertain and varies as a function of various design parameters that include the user scheduling schemes, the transmit power distribution among multiple allocated subcarriers, the partitioning of the cellular region into cell-edge and cell-center zones, the allocation of spectrum within each zone, and the channel reuse factors. To this end, this paper derives a generic analytical model for uplink CCI in multicarrier OFDMA networks with FFR. The derived expressions capture several network design parameters and are applicable to any composite fading-channel models. The accuracy of the derivations is verified via Monte Carlo simulations. Moreover, their usefulness is demonstrated by obtaining closed-form expressions for the Rayleigh fading-channel model and by evaluating important network performance metrics such as ergodic capacity. Numerical results provide useful system design guidelines and highlight the trade-offs associated with the deployment of FFR schemes in OFDMA-based networks. © 2013 IEEE.

A generic interference model for uplink OFDMA networks with fractional frequency reuse

KAUST Repository

Tabassum, Hina; Dawy, Zaher; Alouini, Mohamed-Slim; Yilmaz, Ferkan

2014-01-01

Fractional frequency reuse (FFR) has emerged as a viable solution to coordinate and mitigate cochannel interference (CCI) in orthogonal frequency-division multiple-access (OFDMA)-based wireless cellular networks. The incurred CCI in cellular networks with FFR is highly uncertain and varies as a function of various design parameters that include the user scheduling schemes, the transmit power distribution among multiple allocated subcarriers, the partitioning of the cellular region into cell-edge and cell-center zones, the allocation of spectrum within each zone, and the channel reuse factors. To this end, this paper derives a generic analytical model for uplink CCI in multicarrier OFDMA networks with FFR. The derived expressions capture several network design parameters and are applicable to any composite fading-channel models. The accuracy of the derivations is verified via Monte Carlo simulations. Moreover, their usefulness is demonstrated by obtaining closed-form expressions for the Rayleigh fading-channel model and by evaluating important network performance metrics such as ergodic capacity. Numerical results provide useful system design guidelines and highlight the trade-offs associated with the deployment of FFR schemes in OFDMA-based networks. © 2013 IEEE.

Blind Demodulation of Pass Band OFDMA Signals and Jamming Battle Damage Assessment Utilizing Link Adaptation

Science.gov (United States)

2014-03-27

Access (OFDMA) signal so that jamming effectiveness can be assessed; referred to in this research as Battle Damage Assessment ( BDA ). The research extends...the 802.16 Wireless Metropolitan Area Network (MAN) OFDMA standard, and presents a novel method for performing BDA via observation of Sub Carrier (SC...interferer is also evaluated where the blind demodulator’s performance is degraded. BDA is achieved via observing SC LA modulation behavior of the

Analytical Evaluation of Chunk-Based Tractable Multi-cell OFDMA system

Directory of Open Access Journals (Sweden)

P.Kavitha

2018-04-01

Full Text Available This paper evaluates thoroughly the performance of multi-cell OFDMA system. The two types of deployment in multi-cell OFDMA system, such as Strict Fractional Frequency Reuse (FFR and Soft FFR (SFR were evaluated. In order to model the base station locations, homogeneous Poisson point processes were used, i.e. tractable model instead of hexagonal grid was considered. In order to reduce complexity, chunk-based resource allocation scheme was embedded. Each cell divides the users into the users of the central cell area and the users of the cell edge area according to their average received Signal to Interference and Noise Ratio (SINR compared with FFR threshold. The primary stage of the analysis includes the spectral efficiency’s expression deriving from these two deployment scenarios, followed by the analysis with the use of coverage probability. However, the improvement of spectral efficiency is achieved in the case of SFR. On the contrary, coverage probability is far improved by using strict FFR scheme. Through numerical anaysis, We have shown that the optimal FFR threshold to achieve the highest spectral efficiency was 12 dB for both Strict FFR as well as SFR.

Error-rate performance analysis of cooperative OFDMA system with decode-and-forward relaying

KAUST Repository

Fareed, Muhammad Mehboob; Uysal, Murat; Tsiftsis, Theodoros A.

2014-01-01

In this paper, we investigate the performance of a cooperative orthogonal frequency-division multiple-access (OFDMA) system with decode-and-forward (DaF) relaying. Specifically, we derive a closed-form approximate symbol-error-rate expression and analyze the achievable diversity orders. Depending on the relay location, a diversity order up to (LSkD + 1) + σ M m = 1 min(LSkRm + 1, LR mD + 1) is available, where M is the number of relays, and LS kD + 1, LSkRm + 1, and LRmD + 1 are the lengths of channel impulse responses of source-to-destination, source-to- mth relay, and mth relay-to-destination links, respectively. Monte Carlo simulation results are also presented to confirm the analytical findings. © 2013 IEEE.

Error-rate performance analysis of cooperative OFDMA system with decode-and-forward relaying

KAUST Repository

Fareed, Muhammad Mehboob

2014-06-01

In this paper, we investigate the performance of a cooperative orthogonal frequency-division multiple-access (OFDMA) system with decode-and-forward (DaF) relaying. Specifically, we derive a closed-form approximate symbol-error-rate expression and analyze the achievable diversity orders. Depending on the relay location, a diversity order up to (LSkD + 1) + σ M m = 1 min(LSkRm + 1, LR mD + 1) is available, where M is the number of relays, and LS kD + 1, LSkRm + 1, and LRmD + 1 are the lengths of channel impulse responses of source-to-destination, source-to- mth relay, and mth relay-to-destination links, respectively. Monte Carlo simulation results are also presented to confirm the analytical findings. © 2013 IEEE.

Multiuser Radio Resource Allocation for Multiservice Transmission in OFDMA-Based Cooperative Relay Networks

Directory of Open Access Journals (Sweden)

Zhang Xing

2009-01-01

Full Text Available Abstract The problem of multiservice transmission in OFDMA-based cooperative relay networks is studied comprehensively. We propose a framework to adaptively allocate power, subcarriers, and data rate in OFDMA system to maximize spectral efficiency under the constraints of satisfying multiuser multiservices' QoS requirements. Specifically, first we concentrate on the single-user scenario which considers multiservice transmission in point-to-point cooperative relay network. Based on the analysis of single-user scenario, we extend the multiservice transmission to multiuser point-to-multipoint scenario. Next, based on the framework, we propose several suboptimal radio resource allocation algorithms for multiservice transmissions in OFDMA-based cooperative relay networks to further reduce the computational complexity. Simulation results show that the proposed algorithms yield much higher spectral efficiency and much lower outage probability, which are flexible and efficient for the OFDMA-based cooperative relay system.

Sum rate maximization in the uplink of multi-cell OFDMA networks

KAUST Repository

Tabassum, Hina

2012-10-03

Resource allocation in orthogonal frequency division multiple access (OFDMA) networks plays an imperative role to guarantee the system performance. However, most of the known resource allocation schemes are focused on maximizing the local throughput of each cell, while ignoring the significant effect of inter-cell interference. This paper investigates the problem of resource allocation (i.e., subcarriers and powers) in the uplink of a multi-cell OFDMA network. The problem has a non-convex combinatorial structure and is known to be NP hard. Firstly, we investigate the upper and lower bounds to the average network throughput due to the inherent complexity of implementing the optimal solution. Later, a centralized sub-optimal resource allocation scheme is developed. We further develop less complex centralized and distributed schemes that are well-suited for practical scenarios. The computational complexity of all schemes has been analyzed and the performance is compared through numerical simulations. Simulation results demonstrate that the distributed scheme achieves comparable performance to the centralized resource allocation scheme in various scenarios. © 2011 IEEE.

Link adaptation algorithm for distributed coded transmissions in cooperative OFDMA systems

DEFF Research Database (Denmark)

Varga, Mihaly; Badiu, Mihai Alin; Bota, Vasile

2015-01-01

This paper proposes a link adaptation algorithm for cooperative transmissions in the down-link connection of an OFDMA-based wireless system. The algorithm aims at maximizing the spectral efficiency of a relay-aided communication link, while satisfying the block error rate constraints at both...... adaptation algorithm has linear complexity with the number of available resource blocks, while still provides a very good performance, as shown by simulation results....

Downlink Radio Resource Management for QoS Provisioning in OFDMA Systems

DEFF Research Database (Denmark)

Monghal, Guillaume Damien

Admission Control solution for a realistic OFDMA based system in downlink where LTE is taken as a case study. In the frame of the thesis work, a detailed system model of LTE dedicated to Radio Resource Management study has been developed and implemented in a semi-static system level simulator. In a first...... phase, the study focuses on the dual time / frequency domain packet scheduling concept which allows a linear complexity. Fundamental design principles for throughput control are highlighted. Using those principles, the design of a complete Quality of Service aware packet scheduling algorithm based...

Experimental demonstration of an improved EPON architecture using OFDMA for bandwidth scalable LAN emulation

DEFF Research Database (Denmark)

Deng, Lei; Zhao, Ying; Yu, Xianbin

2011-01-01

We propose and demonstrate an improved Ethernet passive optical network (EPON) architecture supporting bandwidth-scalable physical layer local area network (LAN) emulation. Due to the use of orthogonal frequency division multiple access (OFDMA) technology for the LAN traffic transmission, there i...

Multiuser Carrier Frequency Offset Estimation for OFDMA Uplink Based on Multi-Antenna

Science.gov (United States)

Zhang, Weile; Wang, Junsong; Yin, Qinye; Feng, Ang

In this letter, a novel method is proposed for carrier-frequency offset (CFO) estimation for multiple users in orthogonal frequency division multiple access (OFDMA) uplink with the generalized carrier assignment scheme (GCAS). The base station (BS) is equipped with multiple antennas, and each user's CFO can be estimated by the ESPRIT-like method that utilizes the rotation invariance of the space-domain snapshot matrix. The method is still effective even in fully loaded system with all subcarriers allocated to users. Simulation results illustrate the high performance of the proposed algorithm.

Location-based resource allocation for OFDMA cognitive radio systems

KAUST Repository

Nam, Haewoon

2010-01-01

In cognitive radio systems, in order for the secondary users to opportunistically share the spectrum without interfering the primary users, an accurate spectrum measurement and a precise estimation of the interference at the primary users are necessary but are challenging tasks. Since it is impractical in cognitive radio systems to assume that the channel state information of the interference link is available at the cognitive transmitter, the interference at the primary users is hard to be estimated accurately. This paper introduces a resource allocation algorithm for OFDMA-based cognitive radio systems, which utilizes location information of the primary and secondary users instead of the channel state information of the interference link. Simulation results show that it is indeed effective to incorporate location information into resource allocation so that a near-optimal capacity is achieved.

Reduced feedback selective cluster index scheduling with user pre-selection for next-generation multi-input multi-output orthogonal frequency division multiple access system

OpenAIRE

Nicolaou, M; Doufexi, A; Armour, SMD; Sun, Y

2011-01-01

The joint use of opportunistic scheduling and orthogonal frequency division multiple access (OFDMA) provide significant gains in environments of low mobility and scatter for which channel variations are low. The downside of opportunistic scheduling in multicarrier systems such as OFDMA, lies in the substantial uplink overhead required to feed back by the mobile stations (MSs) describing users' instantaneous link conditions. This study presents a novel approach towards multicarrier opportunist...

Efficient Design of OFDMA-Based Programmable Wireless Radios

Directory of Open Access Journals (Sweden)

Shah SFA

2008-01-01

Full Text Available With the increasing demand for efficient spectrum management, programmable wireless radios can potentially play a key role in shaping our future spectrum use. In this paper, we consider the design of low-power programmable wireless radios based on orthogonal frequency division multiple access (OFDMA. To meet the demands of higher data rate communications, we split OFDMA symbols carrying multiuser data across several noncontiguous bands of available spectrum. To relax power consumption in analog-to-digital and digital-to-analog converters, we use a programmable narrowband RF front end comprising of programmable synthesizers and fixed low-pass filters. To perform digital baseband signal processing in an energy efficient manner, we propose efficient designs for the fast Fourier transform (FFT and inverse FFT (IFFT modules. Our designs of the FFT/IFFT modules reduce power consumption and chip area, and are capable of handling the dynamic nature of spectrum in programmable radios. To recover data that falls within the transition band of the filters, we propose a combiner similar to maximal ratio combiner. We also present the complete design of programmable wireless radios in accordance with the IEEE 802.22 (draft standard.

Efficient Design of OFDMA-Based Programmable Wireless Radios

Directory of Open Access Journals (Sweden)

A. H. Tewfik

2008-03-01

Full Text Available With the increasing demand for efficient spectrum management, programmable wireless radios can potentially play a key role in shaping our future spectrum use. In this paper, we consider the design of low-power programmable wireless radios based on orthogonal frequency division multiple access (OFDMA. To meet the demands of higher data rate communications, we split OFDMA symbols carrying multiuser data across several noncontiguous bands of available spectrum. To relax power consumption in analog-to-digital and digital-to-analog converters, we use a programmable narrowband RF front end comprising of programmable synthesizers and fixed low-pass filters. To perform digital baseband signal processing in an energy efficient manner, we propose efficient designs for the fast Fourier transform (FFT and inverse FFT (IFFT modules. Our designs of the FFT/IFFT modules reduce power consumption and chip area, and are capable of handling the dynamic nature of spectrum in programmable radios. To recover data that falls within the transition band of the filters, we propose a combiner similar to maximal ratio combiner. We also present the complete design of programmable wireless radios in accordance with the IEEE 802.22 (draft standard.

Ant Colony Optimization Algorithm for Centralized Dynamic Channel Allocation in Multi-Cell OFDMA Systems

Science.gov (United States)

Kim, Hyo-Su; Kim, Dong-Hoi

The dynamic channel allocation (DCA) scheme in multi-cell systems causes serious inter-cell interference (ICI) problem to some existing calls when channels for new calls are allocated. Such a problem can be addressed by advanced centralized DCA design that is able to minimize ICI. Thus, in this paper, a centralized DCA is developed for the downlink of multi-cell orthogonal frequency division multiple access (OFDMA) systems with full spectral reuse. However, in practice, as the search space of channel assignment for centralized DCA scheme in multi-cell systems grows exponentially with the increase of the number of required calls, channels, and cells, it becomes an NP-hard problem and is currently too complicated to find an optimum channel allocation. In this paper, we propose an ant colony optimization (ACO) based DCA scheme using a low-complexity ACO algorithm which is a kind of heuristic algorithm in order to solve the aforementioned problem. Simulation results demonstrate significant performance improvements compared to the existing schemes in terms of the grade of service (GoS) performance and the forced termination probability of existing calls without degrading the system performance of the average throughput.

A cross-layer resource allocation scheme for spatial multiplexing-based MIMO-OFDMA systems

Directory of Open Access Journals (Sweden)

Al-Shatri Hussein

2011-01-01

Full Text Available Abstract We investigate the resource allocation problem for the downlink of a multiple-input multiple-output orthogonal frequency division multiple access (MIMO-OFDMA system. The sum rate maximization itself cannot cope with fairness among users. Hence, we address this problem in the context of the utility-based resource allocation presented in earlier papers. This resource allocation method allows to enhance the efficiency and guarantee fairness among users by exploiting multiuser diversity, frequency diversity, as well as time diversity. In this paper, we treat the overall utility as the quality of service indicator and design utility functions with respect to the average transmission rate in order to simultaneously provide two services, real-time and best-effort. Since the optimal solutions are extremely computationally complex to obtain, we propose a suboptimal joint subchannel and power control algorithm that converges very fast and simplifies the MIMO resource allocation problem into a single-input single-output resource allocation problem. Simulation results indicate that using the proposed method achieves near-optimum solutions, and the available resources are distributed more fairly among users.

Distributed Synchronization Technique for OFDMA-Based Wireless Mesh Networks Using a Bio-Inspired Algorithm

Directory of Open Access Journals (Sweden)

Mi Jeong Kim

2015-07-01

Full Text Available In this paper, a distributed synchronization technique based on a bio-inspired algorithm is proposed for an orthogonal frequency division multiple access (OFDMA-based wireless mesh network (WMN with a time difference of arrival. The proposed time- and frequency-synchronization technique uses only the signals received from the neighbor nodes, by considering the effect of the propagation delay between the nodes. It achieves a fast synchronization with a relatively low computational complexity because it is operated in a distributed manner, not requiring any feedback channel for the compensation of the propagation delays. In addition, a self-organization scheme that can be effectively used to construct 1-hop neighbor nodes is proposed for an OFDMA-based WMN with a large number of nodes. The performance of the proposed technique is evaluated with regard to the convergence property and synchronization success probability using a computer simulation.

Distributed Synchronization Technique for OFDMA-Based Wireless Mesh Networks Using a Bio-Inspired Algorithm.

Science.gov (United States)

Kim, Mi Jeong; Maeng, Sung Joon; Cho, Yong Soo

2015-07-28

In this paper, a distributed synchronization technique based on a bio-inspired algorithm is proposed for an orthogonal frequency division multiple access (OFDMA)-based wireless mesh network (WMN) with a time difference of arrival. The proposed time- and frequency-synchronization technique uses only the signals received from the neighbor nodes, by considering the effect of the propagation delay between the nodes. It achieves a fast synchronization with a relatively low computational complexity because it is operated in a distributed manner, not requiring any feedback channel for the compensation of the propagation delays. In addition, a self-organization scheme that can be effectively used to construct 1-hop neighbor nodes is proposed for an OFDMA-based WMN with a large number of nodes. The performance of the proposed technique is evaluated with regard to the convergence property and synchronization success probability using a computer simulation.

An orthogonal wavelet division multiple-access processor architecture for LTE-advanced wireless/radio-over-fiber systems over heterogeneous networks

Science.gov (United States)

Mahapatra, Chinmaya; Leung, Victor CM; Stouraitis, Thanos

2014-12-01

The increase in internet traffic, number of users, and availability of mobile devices poses a challenge to wireless technologies. In long-term evolution (LTE) advanced system, heterogeneous networks (HetNet) using centralized coordinated multipoint (CoMP) transmitting radio over optical fibers (LTE A-ROF) have provided a feasible way of satisfying user demands. In this paper, an orthogonal wavelet division multiple-access (OWDMA) processor architecture is proposed, which is shown to be better suited to LTE advanced systems as compared to orthogonal frequency division multiple access (OFDMA) as in LTE systems 3GPP rel.8 (3GPP, http://www.3gpp.org/DynaReport/36300.htm). ROF systems are a viable alternative to satisfy large data demands; hence, the performance in ROF systems is also evaluated. To validate the architecture, the circuit is designed and synthesized on a Xilinx vertex-6 field-programmable gate array (FPGA). The synthesis results show that the circuit performs with a clock period as short as 7.036 ns (i.e., a maximum clock frequency of 142.13 MHz) for transform size of 512. A pipelined version of the architecture reduces the power consumption by approximately 89%. We compare our architecture with similar available architectures for resource utilization and timing and provide performance comparison with OFDMA systems for various quality metrics of communication systems. The OWDMA architecture is found to perform better than OFDMA for bit error rate (BER) performance versus signal-to-noise ratio (SNR) in wireless channel as well as ROF media. It also gives higher throughput and mitigates the bad effect of peak-to-average-power ratio (PAPR).

Reduced feedback opportunistic and layered random beamforming for MIMO-OFDMA systems

OpenAIRE

Han, C; Nicolaou, M; Doufexi, A; Armour, SMD

2007-01-01

This paper considers a number of techniques employed in opportunistic and layered random beamforming OFDMA schemes that aim to reduce the feedback required to perform scheduling whilst also minimising the throughput degradations resulting from this reduced throughput (due to the lack of full CSI at the Base Station (BS). Frequency response correlation among subcarriers can be exploited to group adjacent subcarriers into clusters which can then be treated as a single unit for feedback purposes...

Analysis Framework for Opportunistic Spectrum OFDMA and its Application to the IEEE 802.22 Standard

OpenAIRE

Park, Jihoon; Pawełczak, Przemysław; Grønsund, Pål; Čabrić, Danijela

2010-01-01

We present an analytical model that enables throughput evaluation of Opportunistic Spectrum Orthogonal Frequency Division Multiple Access (OS-OFDMA) networks. The core feature of the model, based on a discrete time Markov chain, is the consideration of different channel and subchannel allocation strategies under different Primary and Secondary user types, traffic and priority levels. The analytical model also assesses the impact of different spectrum sensing strategies on the throughput of OS...

Orthogonal frequency division multiple access fundamentals and applications

CERN Document Server

Jiang, Tao; Zhang, Yan

2010-01-01

Supported by the expert-level advice of pioneering researchers, Orthogonal Frequency Division Multiple Access Fundamentals and Applications provides a comprehensive and accessible introduction to the foundations and applications of one of the most promising access technologies for current and future wireless networks. It includes authoritative coverage of the history, fundamental principles, key techniques, and critical design issues of OFDM systems. Covering various techniques of effective resource management for OFDM/OFDMA-based wireless communication systems, this cutting-edge reference:Add

Channel Asymmetry in Cellular OFDMA-TDD Networks

Directory of Open Access Journals (Sweden)

Agyapong Patrick

2008-01-01

Full Text Available Abstract This paper studies time division duplex- (TDD- specific interference issues in orthogonal frequency division multiple access- (OFDMA- TDD cellular networks arising from various uplink (UL/downlink (DL traffic asymmetries, considering both line-of-sight (LOS and non-LOS (NLOS conditions among base stations (BSs. The study explores aspects both of channel allocation and user scheduling. In particular, a comparison is drawn between the fixed slot allocation (FSA technique and a dynamic channel allocation (DCA technique for different UL/DL loads. For the latter, random time slot opposing (RTSO is assumed due to its simplicity and its low signaling overhead. Both channel allocation techniques do not obviate the need for user scheduling algorithms, therefore, a greedy and a fair scheduling approach are applied to both the RTSO and the FSA. The systems are evaluated based on spectral efficiency, subcarrier utilization, and user outage. The results show that RTSO networks with DL-favored traffic asymmetries outperform FSA networks for all considered metrics and are robust to LOS between BSs. In addition, it is demonstrated that the greedy scheduling algorithm only offers a marginal increase in spectral efficiency as compared to the fair scheduling algorithm, while the latter exhibits up to 20% lower outage.

Comparison of Strategies for Signaling of Scheduling Assignments in Wireless OFDMA

OpenAIRE

Moosavi, Reza; Eriksson, Jonas; Larsson, Erik G.; Wiberg, Niclas; Frenger, Pål; Gunnarsson, Fredrik

2010-01-01

This paper considers transmission of scheduling information in  OFDMA-based cellular communication systems such as 3GPP long-term  evolution (LTE). These systems provide efficient usage of radio  resources by allowing users to be scheduled dynamically in both  frequency and time. This requires considerable amounts of scheduling  information to be sent to the users.  The paper compares two basic transmission strategies: transmitting a  separate scheduling message to each user versus broadcasti...

Joint User Scheduling and MU-MIMO Hybrid Beamforming Algorithm for mmWave FDMA Massive MIMO System

Directory of Open Access Journals (Sweden)

Jing Jiang

2016-01-01

Full Text Available The large bandwidth and multipath in millimeter wave (mmWave cellular system assure the existence of frequency selective channels; it is necessary that mmWave system remains with frequency division multiple access (FDMA and user scheduling. But for the hybrid beamforming system, the analog beamforming is implemented by the same phase shifts in the entire frequency band, and the wideband phase shifts may not be harmonious with all users scheduled in frequency resources. This paper proposes a joint user scheduling and multiuser hybrid beamforming algorithm for downlink massive multiple input multiple output (MIMO orthogonal frequency division multiple access (OFDMA systems. In the first step of user scheduling, the users with identical optimal beams form an OFDMA user group and multiplex the entire frequency resource. Then base station (BS allocates the frequency resources for each member of OFDMA user group. An OFDMA user group can be regarded as a virtual user; thus it can support arbitrary MU-MIMO user selection and beamforming algorithms. Further, the analog beamforming vectors employ the best beam of each selected MU-MIMO user and the digital beamforming algorithm is solved by weight MMSE to acquire the best performance gain and mitigate the interuser inference. Simulation results show that hybrid beamforming together with user scheduling can greatly improve the performance of mmWave OFDMA massive MU-MIMO system.

Rate Adaptive OFDMA Communication Systems

International Nuclear Information System (INIS)

Abdelhakim, M.M.M.

2009-01-01

Due to the varying nature of the wireless channels, adapting the transmission parameters, such as code rate, modulation order and power, in response to the channel variations provides a significant improvement in the system performance. In the OFDM systems, Per-Frame adaptation (PFA) can be employed where the transmission variables are fixed over a given frame and may change from one frame to the other. Subband (tile) loading offers more degrees of adaptation such that each group of carriers (subband) uses the same transmission parameters and different subbands may use different parameters. Changing the code rate for each tile in the same frame, results in transmitting multiple codewords (MCWs) for a single frame. In this thesis a scheme is proposed for adaptively changing the code rate of coded OFDMA systems via changing the puncturing rate within a single codeword (SCW). In the proposed structure, the data is encoded with the lowest available code rate then it is divided among the different tiles where it is punctured adaptively based on some measure of the channel quality for each tile. The proposed scheme is compared against using multiple codewords (MCWs) where the different code rates for the tiles are obtained using separate encoding processes. For bit interleaved coded modulation architecture two novel interleaving methods are proposed, namely the puncturing dependant interleaver (PDI) and interleaved puncturing (IntP), which provide larger interleaving depth. In the PDI method the coded bits with the same rate over different tiles are grouped for interleaving. In IntP structure the interleaving is performed prior to puncturing. The performance of the adaptive puncturing technique is investigated under constant bit rate constraint and variable bit rate. Two different adaptive modulation and coding (AMC) selection methods are examined for variable bit rate adaptive system. The first is a recursive scheme that operates directly on the SNR whereas the second

Optimal OFDMA Downlink Scheduling Under a Control Signaling Cost Constraint

OpenAIRE

Larsson, Erik G.

2010-01-01

This paper proposes a new algorithm for downlink scheduling in OFDMA systems. The method maximizes the throughput, taking into account the amount of signaling needed to transmit scheduling maps to the users. A combinatorial problem is formulated and solved via a dynamic programming approach reminiscent of the Viterbi algorithm. The total computational complexity of the algorithm is upper boundedby O(K^4N) where K is the number of users that are being considered for scheduling in a frame and N...

Hermitian symmetry free optical-single-carrier frequency division multiple access for visible light communication

Science.gov (United States)

Azim, Ali W.; Le Guennec, Yannis; Maury, Ghislaine

2018-05-01

Optical-orthogonal frequency division multiplexing (O-OFDM) is an effective scheme for visible light communications (VLC), offering a candid extension to multiple access (MA) scenarios, i.e., O-OFDMA. However, O-OFDMA exhibits high peak-to-average power ratio (PAPR), which exacerbates the non-linear distortions from the light emitting diode (LED). To overcome high PAPR while sustaining MA, optical-single-carrier frequency-division multiple access (O-SCFDMA) is used. For both O-OFDMA and O-SCFDMA, Hermitian symmetry (HS) constraint is imposed in frequency-domain (FD) to obtain a real-valued time-domain (TD) signal for intensity modulation-direct detection (IM-DD) implementation of VLC. Howbeit, HS results in an increase of PAPR for O-SCFDMA. In this regard, we propose HS free (HSF) O-SCFDMA (HSFO-SCFDMA). We compare HSFO-SCFDMA with several approaches in key parameters, such as, bit error rate (BER), optical power penalty, PAPR, quantization, electrical power efficiency and system complexity. BER performance and optical power penalty is evaluated considering multipath VLC channel and taking into account the bandwidth limitation of LED in combination with its optimized driver. It is illustrated that HSFO-SCFDMA outperforms other alternatives.

Combating Impairments in Multi-carrier Systems: A Compressed Sensing Approach

KAUST Repository

Al-Shuhail, Shamael

2015-05-01

Multi-carrier systems suffer from several impairments, and communication system engineers use powerful signal processing tools to combat these impairments and keep up with the capacity/rate demands. Compressed sensing (CS) is one such tool that allows recovering any sparse signal, requiring only a few measurements in a domain that is incoherent with the domain of sparsity. Almost all signals of interest have some degree of sparsity, and in this work we utilize the sparsity of impairments in orthogonal frequency division multiplexing (OFDM) and its variants (i.e., orthogonal frequency division multiplexing access (OFDMA) and single-carrier frequency-division multiple access (SC-FDMA)) to combat them using CS. We start with the problem of peak-to-average power ratio (PAPR) reduction in OFDM. OFDM signals suffer from high PAPR and clipping is the simplest PAPR reduction scheme. However, clipping introduces inband distortions that result in compromised performance and hence needs to be mitigated at the receiver. Due to the high PAPR nature of the OFDM signal, only a few instances are clipped, these clipping distortions can be recovered at the receiver by employing CS. We then extend the proposed clipping recovery scheme to an interleaved OFDMA system. Interleaved OFDMA presents a special structure that result in only self-inflicted clipping distortions. In this work, we prove that distortions do not spread over multiple users (while utilizing interleaved carrier assignment in OFDMA) and construct a CS system that recovers the clipping distortions on each user. Finally, we address the problem of narrowband interference (NBI) in SC-FDMA. Unlike OFDM and OFDMA systems, SC-FDMA does not suffer from high PAPR, but (as the data is encoded in time domain) is seriously vulnerable to information loss owing to NBI. Utilizing the sparse nature of NBI (in frequency domain) we combat its effect on SC-FDMA system by CS recovery.

Weighted-SNR-based fair scheduling for uplink OFDMA

KAUST Repository

Ma, Yao

2009-11-01

In this paper, we study the sum rate maximization algorithms with long-term proportional rate fairness (PRF) for uplink orthogonal frequency division multiple access (OFDMA) systems. In contrast to the rate-maximization schemes which used short-term PRF in the literature, we propose to use a selective multiuser diversity (SMuD) scheme to achieve a long-term PRF and improved sum rate performance. This scheme implements weighted channel signal-to-noise ratio (w-SNR)-based ranking for user selection on each subchannel, and then uses either water-filling (WF) or equal power allocation (EPA) along the assigned channels of each user. Both offline and online methods to find the optimal SNR weight factors are designed to achieve the target proportional rates for different users. The offline optimization technique requires to know the channel distribution information (CDI) at the scheduler. The online method uses the weight adaption combined with individual user rate tracking, which avoids the need to know the CDI. Analytical throughput metrics for the proposed w-SNR scheme with WF and EPA over Rayleigh channels are derived, and verified by simulations. Simulation results show that the proposed w-SNR PRF scheme can achieve significantly higher sum rates than the frequency diversity-based short-term and long-term fairness schemes. Besides the improved performance, the proposed schemes have a low complexity which is linear to numbers of users and subchannels.

Uplink Cross-Layer Scheduling with Differential QoS Requirements in OFDMA Systems

Directory of Open Access Journals (Sweden)

Chen Wei

2010-01-01

Full Text Available Fair and efficient scheduling is a key issue in cross-layer design for wireless communication systems, such as 3GPP LTE and WiMAX. However, few works have considered the multiaccess of the traffic with differential QoS requirements in wireless systems. In this paper, we will consider an OFDMA-based wireless system with four types of traffic associated with differential QoS requirements, namely, minimum reserved rate, maximum sustainable rate, maximum latency, and tolerant jitter. Given these QoS requirements, the traffic scheduling will be formulated into a cross-layer optimization problem, which is convex fortunately. By separating the power allocation through the waterfilling algorithm in each user, this problem will further reduce to a kind of continuous quadratic knapsack problem in the base station which yields low complexity. It is then demonstrated that the proposed cross-layer method cannot only guarantee the application layer QoS requirements, but also minimizes the integrated residual workload in the MAC layer. To further enhance the ability of QoS assurance in heavily loaded scenario, a call admission control scheme will also be proposed. The simulation results show that the QoS requirements for the four types of traffic are guaranteed effectively by the proposed algorithms.

Sum rate maximization in the uplink of multi-cell OFDMA networks

KAUST Repository

Tabassum, Hina; Alouini, Mohamed-Slim; Dawy, Zaher

2012-01-01

of each cell, while ignoring the significant effect of inter-cell interference. This paper investigates the problem of resource allocation (i.e., subcarriers and powers) in the uplink of a multi-cell OFDMA network. The problem has a non

Resource Allocation for OFDMA-Based Cognitive Radio Networks with Application to H.264 Scalable Video Transmission

Directory of Open Access Journals (Sweden)

Coon JustinP

2011-01-01

Full Text Available Resource allocation schemes for orthogonal frequency division multiple access- (OFDMA- based cognitive radio (CR networks that impose minimum and maximum rate constraints are considered. To demonstrate the practical application of such systems, we consider the transmission of scalable video sequences. An integer programming (IP formulation of the problem is presented, which provides the optimal solution when solved using common discrete programming methods. Due to the computational complexity involved in such an approach and its unsuitability for dynamic cognitive radio environments, we propose to use the method of lift-and-project to obtain a stronger formulation for the resource allocation problem such that the integrality gap between the integer program and its linear relaxation is reduced. A simple branching operation is then performed that eliminates any noninteger values at the output of the linear program solvers. Simulation results demonstrate that this simple technique results in solutions very close to the optimum.

Distributed Multi-Cell Resource Allocation with Price Based ICI Coordination in Downlink OFDMA Networks

Science.gov (United States)

Lv, Gangming; Zhu, Shihua; Hui, Hui

Multi-cell resource allocation under minimum rate request for each user in OFDMA networks is addressed in this paper. Based on Lagrange dual decomposition theory, the joint multi-cell resource allocation problem is decomposed and modeled as a limited-cooperative game, and a distributed multi-cell resource allocation algorithm is thus proposed. Analysis and simulation results show that, compared with non-cooperative iterative water-filling algorithm, the proposed algorithm can remarkably reduce the ICI level and improve overall system performances.

A coalition formation game for transmitter cooperation in OFDMA uplink communications

KAUST Repository

Chelli, Ali

2014-12-01

The SC-FDMA (single-carrier frequency division multiple access) is the access scheme that has been adopted by 3GPP (3rd generation partnership project) for the LTE (long term evolution) uplink. The SC-FDMA is an attractive alternative to OFDMA (orthogonal frequency-division multiple access) especially on the uplink owing to its low peak-to-average power ratio. This fact increases the power efficiency and reduces the cost of the power amplifiers at the mobile terminals. The use of SC-FDMA on the uplink implies that for highly loaded cells the base station allocates a single subcarrier to each user. This results in the limitation of the achievable rate on the uplink. In this work, we propose a coalition game between mobile terminals that allows them to improve their performance by sharing their subcarriers without creating any interference to each other. The proposed scheme allows a fair use of the subcarriers and leads to a significant capacity gain for each user. The cooperation between the nodes is modelled using coalitional game theory. In this game, each coalition tries to maximize its utility in terms of rate. In the absence of cooperation cost, it can be shown that the grand coalition is sum-rate optimal and stable, i.e., the mobile terminals have no incentive to leave the grand coalition.

Spectrally Efficient OFDMA Lattice Structure via Toroidal Waveforms on the Time-Frequency Plane

Directory of Open Access Journals (Sweden)

Sultan Aldirmaz

2010-01-01

Full Text Available We investigate the performance of frequency division multiplexed (FDM signals, where multiple orthogonal Hermite-Gaussian carriers are used to increase the bandwidth efficiency. Multiple Hermite-Gaussian functions are modulated by a data set as a multicarrier modulation scheme in a single time-frequency region constituting toroidal waveform in a rectangular OFDMA system. The proposed work outperforms in the sense of bandwidth efficiency compared to the transmission scheme where only single Gaussian pulses are used as the transmission base. We investigate theoretical and simulation results of the proposed methods.

OFDM Towards Fixed and Mobile Broadband Wireless Access

DEFF Research Database (Denmark)

Shanker Jha, Uma; Prasad, Ramjee

) and orthogonal frequency division multiple access (OFDMA) schemes. Essential features of IEEE 802.16d (fixed) and 802.16e (mobile) and the role of the WiMAX Forum in defining interoperability and certification criteria. Important requirements, trade-offs, and other critical design considerations. Key issues...

Tunable optical frequency comb enabled scalable and cost-effective multiuser orthogonal frequency-division multiple access passive optical network with source-free optical network units.

Science.gov (United States)

Chen, Chen; Zhang, Chongfu; Liu, Deming; Qiu, Kun; Liu, Shuang

2012-10-01

We propose and experimentally demonstrate a multiuser orthogonal frequency-division multiple access passive optical network (OFDMA-PON) with source-free optical network units (ONUs), enabled by tunable optical frequency comb generation technology. By cascading a phase modulator (PM) and an intensity modulator and dynamically controlling the peak-to-peak voltage of a PM driven signal, a tunable optical frequency comb source can be generated. It is utilized to assist the configuration of a multiple source-free ONUs enhanced OFDMA-PON where simultaneous and interference-free multiuser upstream transmission over a single wavelength can be efficiently supported. The proposed multiuser OFDMA-PON is scalable and cost effective, and its feasibility is successfully verified by experiment.

Receiver based PAPR reduction in OFDMA

KAUST Repository

Ali, Anum Z.; Al-Zahrani, Ali Y.; Al-Naffouri, Tareq Y.; Naguib, Ayman F.

2014-01-01

High peak-to-average power ratio is one of the major drawbacks of orthogonal frequency division multiplexing (OFDM). Clipping is the simplest peak reduction scheme, however, it requires clipping mitigation at the receiver. Recently compressed sensing has been used for clipping mitigation (by exploiting the sparse nature of clipping signal). However, clipping estimation in multi-user scenario (i.e., OFDMA) is not straightforward as clipping distortions overlap in frequency domain and one cannot distinguish between distortions from different users. In this work, a collaborative clipping removal strategy is proposed based on joint estimation of the clipping distortions from all users. Further, an effective data aided channel estimation strategy for clipped OFDM is also outlined. Simulation results are presented to justify the effectiveness of the proposed schemes. © 2014 IEEE.

Receiver based PAPR reduction in OFDMA

KAUST Repository

Ali, Anum Z.

2014-05-01

High peak-to-average power ratio is one of the major drawbacks of orthogonal frequency division multiplexing (OFDM). Clipping is the simplest peak reduction scheme, however, it requires clipping mitigation at the receiver. Recently compressed sensing has been used for clipping mitigation (by exploiting the sparse nature of clipping signal). However, clipping estimation in multi-user scenario (i.e., OFDMA) is not straightforward as clipping distortions overlap in frequency domain and one cannot distinguish between distortions from different users. In this work, a collaborative clipping removal strategy is proposed based on joint estimation of the clipping distortions from all users. Further, an effective data aided channel estimation strategy for clipped OFDM is also outlined. Simulation results are presented to justify the effectiveness of the proposed schemes. © 2014 IEEE.

Calibration and Evaluation of Fixed and Mobile Relay-Based System Level Simulator

Directory of Open Access Journals (Sweden)

Shahid Mumtaz

2010-01-01

Full Text Available Future wireless communication systems are expected to provide more stable and higher data rate transmissions in the whole OFDMA networks, but the mobile stations (MSs in the cell boundary experience poor spectral efficiency due to the path loss from the transmitting antenna and interference from adjacent cells. Therefore, satisfying QoS (Quality of Service requirements of each MS at the cell boundary has been an important issue. To resolve this spectral efficiency problem at the cell boundary, deploying relay stations has been actively considered. As multihop/relay has complex interactions between the routing and medium access control decisions, the extent to which analytical expressions can be used to explore its benefits is limited. Consequently, simulations tend to be the preferred way of assessing the performance of relays. In this paper, we evaluate the performance of relay-assisted OFDMA networks by means of system level simulator (SLS. We consistently observed that the throughput is increased and the outage is decreased in the relay-assisted OFDMA network, which is converted to range extension without any capacity penalty, for the realistic range of values of the propagation and other system parameters investigated.

Variable Delay With Directly-Modulated R-SOA and Optical Filters for Adaptive Antenna Radio-Fiber Access

DEFF Research Database (Denmark)

Prince, Kamau; Presi, Marco; Chiuchiarelli, Andrea

2009-01-01

types of signals defined in IEEE 802.16 (WiMAX) standard for wireless networks: a 90 Mbps single-carrier signal (64-QAM at 2.4 GHz) and a 78 Mbps multitone orthogonal frequency-division multiple access (OFDMA) signal. The power budget of this configuration supports a 4-element antenna array....... on a directly-modulated reflective emiconductor amplifier (R-SOA) and exploits the interplay between transmission-line dispersion and tunable optical filtering to achieve flexible true time delay, with $2pi$ beam steering at the different antennas. The system was characterized, then successfully tested with two...

Fairness-Aware Energy-Efficient Resource Allocation for AF Co-Operative OFDMA Networks

KAUST Repository

Bedeer, Ebrahim

2015-09-23

In this paper, we adopt an energy-efficiency (EE) metric, named worst-EE, that is suitable for EE fairness optimization in the uplink transmission of amplify-and-forward (AF) cooperative orthogonal frequency division multiple access (OFDMA) networks. More specifically, we assign subcarriers and allocate powers for mobile and relay stations in order to maximize the worst-EE, i.e., to maximize the EE of the mobile station (MS) with the lowest EE value, subject to MSs transmit power, relay station (RS) transmit power, and MSs quality-of-service (QoS) constraints. The formulated primal max-min optimization problem is nonconvex fractional mixed integer nonlinear program, i.e., NP-hard to solve. We provide a novel optimization framework that studies the structure of the primal problem and prove that the dual min-max optimization problem attains the same optimal solution of the primal problem. Additionally, we propose a modified Dinkelbach algorithm, named dual Dinkelbach, to achieve the optimal solution of the dual problem in a polynomial time complexity. We further exploit the structure of the obtained optimal solution and develop a low complexity suboptimal heuristic. Numerical results show the effectiveness of the proposed algorithm to improve the network performance in terms of fairness between MSs, worst-EE, and average network transmission rate when compared to traditional schemes that maximize the EE of the whole network. Presented results also show that the suboptimal heuristic balances the achieved performance and the computational complexity.

Fairness-Aware Energy-Efficient Resource Allocation for AF Co-Operative OFDMA Networks

KAUST Repository

Bedeer, Ebrahim; Alorainy, Abdulaziz; Hossain, Md. Jahangir; Amin, Osama; Alouini, Mohamed-Slim

2015-01-01

In this paper, we adopt an energy-efficiency (EE) metric, named worst-EE, that is suitable for EE fairness optimization in the uplink transmission of amplify-and-forward (AF) cooperative orthogonal frequency division multiple access (OFDMA) networks. More specifically, we assign subcarriers and allocate powers for mobile and relay stations in order to maximize the worst-EE, i.e., to maximize the EE of the mobile station (MS) with the lowest EE value, subject to MSs transmit power, relay station (RS) transmit power, and MSs quality-of-service (QoS) constraints. The formulated primal max-min optimization problem is nonconvex fractional mixed integer nonlinear program, i.e., NP-hard to solve. We provide a novel optimization framework that studies the structure of the primal problem and prove that the dual min-max optimization problem attains the same optimal solution of the primal problem. Additionally, we propose a modified Dinkelbach algorithm, named dual Dinkelbach, to achieve the optimal solution of the dual problem in a polynomial time complexity. We further exploit the structure of the obtained optimal solution and develop a low complexity suboptimal heuristic. Numerical results show the effectiveness of the proposed algorithm to improve the network performance in terms of fairness between MSs, worst-EE, and average network transmission rate when compared to traditional schemes that maximize the EE of the whole network. Presented results also show that the suboptimal heuristic balances the achieved performance and the computational complexity.

MAI-free performance of PMU-OFDM transceiver in time-variant environment

Science.gov (United States)

Tadjpour, Layla; Tsai, Shang-Ho; Kuo, C.-C. J.

2005-06-01

An approximately multi-user OFDM transceiver was introduced to reduce the multi-access interference (MAI ) due to the carrier frequency offset (CFO) to a negligible amount via precoding by Tsai, Lin and Kuo. In this work, we investigate the performance of this precoded multi-user (PMU) OFDM system in a time-variant channel environment. We analyze and compare the MAI effect caused by time-variant channels in the PMU-OFDM and the OFDMA systems. Generally speaking, the MAI effect consists of two parts. The first part is due to the loss of orthogonality among subchannels for all users while the second part is due to the CFO effect caused by the Doppler shift. Simulation results show that, although OFDMA outperforms the PMU-OFDM transceiver in a fast time-variant environment without CFO, PMU-OFDM outperforms OFDMA in a slow time-variant channel via the use of M/2 symmetric or anti-symmetric codewords of M Hadamard-Walsh codes.

Performance of Downlink UTRAN LTE under Control Channel Constraints

DEFF Research Database (Denmark)

López Villa, Dimas; Úbeda Castellanos, Carlos; Kovács, István Z.

2008-01-01

Dynamic time-frequency domain packet scheduling algorithms in the shared channel of downlink orthogonal Frequency Division Multiple Access (OFDMA) systems have been shown to achieve high multi-user diversity scheduling gains. However, the flexibility is obtained at the cost of additional control ...

Adaptive Modulation for a Downlink Multicast Channel in OFDMA Systems

DEFF Research Database (Denmark)

Wang, Haibo; Schwefel, Hans-Peter; Toftegaard, Thomas Skjødeberg

2007-01-01

In this paper we focus on adaptive modulation strategies for multicast service in orthogonal frequency division multiple access systems. A reward function has been defined as the optimization target, which includes both the average user throughput and bit error rate. We also developed an adaptive...... modulation strategy, namely local best reward strategy, to maximize this reward function. The performance of different modulation strategies are compared in different SNR distribution scenarios, and the optimum strategy in each scenario is suggested....

Dynamic Resource Allocation in Hybrid Access Femtocell Network

Directory of Open Access Journals (Sweden)

Afaz Uddin Ahmed

2014-01-01

Full Text Available 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.

Spectral Efficiency Analysis for Multicarrier Based 4G Systems

DEFF Research Database (Denmark)

Silva, Nuno; Rahman, Muhammad Imadur; Frederiksen, Flemming Bjerge

2006-01-01

In this paper, a spectral efficiency definition is proposed. Spectral efficiency for multicarrier based multiaccess techniques, such as OFDMA, MC-CDMA and OFDMA-CDM, is analyzed. Simulations for different indoor and outdoor scenarios are carried out. Based on the simulations, we have discussed ho...

Iterative Signal Processing for Mitigation of Analog-to-Digital Converter Clipping Distortion in Multiband OFDMA Receivers

Directory of Open Access Journals (Sweden)

Markus Allén

2012-01-01

Full Text Available In modern wideband communication receivers, the large input-signal dynamics is a fundamental problem. Unintentional signal clipping occurs, if the receiver front-end with the analog-to-digital interface cannot respond to rapidly varying conditions. This paper discusses digital postprocessing compensation of such unintentional clipping in multiband OFDMA receivers. The proposed method iteratively mitigates the clipping distortion by exploiting the symbol decisions. The performance of the proposed method is illustrated with various computer simulations and also verified by concrete laboratory measurements with commercially available analog-to-digital hardware. It is shown that the clipping compensation algorithm implemented in a turbo decoding OFDM receiver is able to remove almost all the clipping distortion even under significant clipping in fading channel circumstances. That is to say, it is possible to nearly recover the receiver performance to the level, which would be achieved in the equivalent nonclipped situation.

History-based Adaptive Modulation for a Downlink Multicast Channel in OFDMA systems

DEFF Research Database (Denmark)

Wang, Haibo; Schwefel, Hans-Peter; Toftegaard, Thomas Skjødeberg

2008-01-01

In this paper we investigated the adaptive modulation strategies for Multicast service in orthogonal frequency division multiple access systems. We defined a Reward function as the performance optimization target and developed adaptive modulation strategies to maximize this Reward function....... The proposed optimization algorithm varied the instantaneous BER constraint of each mobile Multicast receiver according to its individual cumulated BER, which resulted in a significant Reward gain....

Secure physical layer using dynamic permutations in cognitive OFDMA systems

DEFF Research Database (Denmark)

Meucci, F.; Wardana, Satya Ardhy; Prasad, Neeli R.

2009-01-01

This paper proposes a novel lightweight mechanism for a secure Physical (PHY) layer in Cognitive Radio Network (CRN) using Orthogonal Frequency Division Multiplexing (OFDM). User's data symbols are mapped over the physical subcarriers with a permutation formula. The PHY layer is secured...... with a random and dynamic subcarrier permutation which is based on a single pre-shared information and depends on Dynamic Spectrum Access (DSA). The dynamic subcarrier permutation is varying over time, geographical location and environment status, resulting in a very robust protection that ensures...... confidentiality. The method is shown to be effective also for existing non-cognitive systems. The proposed mechanism is effective against eavesdropping even if the eavesdropper adopts a long-time patterns analysis, thus protecting cryptography techniques of higher layers. The correlation properties...

RLAM: A Dynamic and Efficient Reinforcement Learning-Based Adaptive Mapping Scheme in Mobile WiMAX Networks

Directory of Open Access Journals (Sweden)

M. Louta

2014-01-01

Full Text Available WiMAX (Worldwide Interoperability for Microwave Access constitutes a candidate networking technology towards the 4G vision realization. By adopting the Orthogonal Frequency Division Multiple Access (OFDMA technique, the latest IEEE 802.16x amendments manage to provide QoS-aware access services with full mobility support. A number of interesting scheduling and mapping schemes have been proposed in research literature. However, they neglect a considerable asset of the OFDMA-based wireless systems: the dynamic adjustment of the downlink-to-uplink width ratio. In order to fully exploit the supported mobile WiMAX features, we design, develop, and evaluate a rigorous adaptive model, which inherits its main aspects from the reinforcement learning field. The model proposed endeavours to efficiently determine the downlink-to-uplinkwidth ratio, on a frame-by-frame basis, taking into account both the downlink and uplink traffic in the Base Station (BS. Extensive evaluation results indicate that the model proposed succeeds in providing quite accurate estimations, keeping the average error rate below 15% with respect to the optimal sub-frame configurations. Additionally, it presents improved performance compared to other learning methods (e.g., learning automata and notable improvements compared to static schemes that maintain a fixed predefined ratio in terms of service ratio and resource utilization.

Single Carrier Transmission for UTRA LTE Uplink

DEFF Research Database (Denmark)

Priyanto, Basuki Endah; Berardinelli, Gilberto; Sørensen, Troels Bundgaard

2009-01-01

In this chapter, we have presented the key techniques for LTE uplink as well as presented the baseline performance. Radio access technology is the key aspect in LTE uplink and two radio access schemes, SC-FDMA and OFDMA, are studied. The performance results are obtained from a detailed UTRA LTE...

Access control system operation

International Nuclear Information System (INIS)

Barnes, L.D.

1981-06-01

An automated method for the control and monitoring of personnel movement throughout the site was developed under contract to the Department of Energy by Allied-General Nuclear Services (AGNS) at the Barnwell Nuclear Fuel Plant (BNFP). These automated features provide strict enforcement of personnel access policy without routine patrol officer involvement. Identification methods include identification by employee ID number, identification by voice verification and identification by physical security officer verification. The ability to grant each level of access authority is distributed over the organization to prevent any single individual at any level in the organization from being capable of issuing an authorization for entry into sensitive areas. Each access event is recorded. As access events occur, the inventory of both the entered and the exited control area is updated so that a current inventory is always available for display. The system has been operated since 1979 in a development mode and many revisions have been implemented in hardware and software as areas were added to the system. Recent changes have involved the installation of backup systems and other features required to achieve a high reliability. The access control system and recent operating experience are described

ARCAS (ACACIA Regional Climate-data Access System) -- a Web Access System for Climate Model Data Access, Visualization and Comparison

Science.gov (United States)

Hakkarinen, C.; Brown, D.; Callahan, J.; hankin, S.; de Koningh, M.; Middleton-Link, D.; Wigley, T.

2001-05-01

A Web-based access system to climate model output data sets for intercomparison and analysis has been produced, using the NOAA-PMEL developed Live Access Server software as host server and Ferret as the data serving and visualization engine. Called ARCAS ("ACACIA Regional Climate-data Access System"), and publicly accessible at http://dataserver.ucar.edu/arcas, the site currently serves climate model outputs from runs of the NCAR Climate System Model for the 21st century, for Business as Usual and Stabilization of Greenhouse Gas Emission scenarios. Users can select, download, and graphically display single variables or comparisons of two variables from either or both of the CSM model runs, averaged for monthly, seasonal, or annual time resolutions. The time length of the averaging period, and the geographical domain for download and display, are fully selectable by the user. A variety of arithmetic operations on the data variables can be computed "on-the-fly", as defined by the user. Expansions of the user-selectable options for defining analysis options, and for accessing other DOD-compatible ("Distributed Ocean Data System-compatible") data sets, residing at locations other than the NCAR hardware server on which ARCAS operates, are planned for this year. These expansions are designed to allow users quick and easy-to-operate web-based access to the largest possible selection of climate model output data sets available throughout the world.

Compressed sensing based joint-compensation of power amplifier's distortions in OFDMA cognitive radio systems

KAUST Repository

Ali, Anum Z.

2013-12-01

Linearization of user equipment power amplifiers driven by orthogonal frequency division multiplexing signals is addressed in this paper. Particular attention is paid to the power efficient operation of an orthogonal frequency division multiple access cognitive radio system and realization of such a system using compressed sensing. Specifically, precompensated overdriven amplifiers are employed at the mobile terminal. Over-driven amplifiers result in in-band distortions and out of band interference. Out of band interference mostly occupies the spectrum of inactive users, whereas the in-band distortions are mitigated using compressed sensing at the receiver. It is also shown that the performance of the proposed scheme can be further enhanced using multiple measurements of the distortion signal in single-input multi-output systems. Numerical results verify the ability of the proposed setup to improve error vector magnitude, bit error rate, outage capacity and mean squared error. © 2011 IEEE.

Compressed sensing based joint-compensation of power amplifier's distortions in OFDMA cognitive radio systems

KAUST Repository

Ali, Anum Z.; Hammi, Oualid; Al-Naffouri, Tareq Y.

2013-01-01

Linearization of user equipment power amplifiers driven by orthogonal frequency division multiplexing signals is addressed in this paper. Particular attention is paid to the power efficient operation of an orthogonal frequency division multiple access cognitive radio system and realization of such a system using compressed sensing. Specifically, precompensated overdriven amplifiers are employed at the mobile terminal. Over-driven amplifiers result in in-band distortions and out of band interference. Out of band interference mostly occupies the spectrum of inactive users, whereas the in-band distortions are mitigated using compressed sensing at the receiver. It is also shown that the performance of the proposed scheme can be further enhanced using multiple measurements of the distortion signal in single-input multi-output systems. Numerical results verify the ability of the proposed setup to improve error vector magnitude, bit error rate, outage capacity and mean squared error. © 2011 IEEE.

The LHC access system LACS and LASS

CERN Document Server

Ninin, P

2005-01-01

The LHC complex is divided into a number of zones with different levels of access controls.Inside the interlocked areas, the personnel protection is ensured by the LHC Access System.The system is made of two parts:the LHC Access Safety System and the LHC Access Control System. During machine operation,the LHC Access Safety System ensures the collective protection of the personnel against the radiation hazards arising from the operation of the accelerator by interlocking the LHC key safety elements. When the beams are off, the LHC Access Control System regulates the access to the accelerator and its many subsystems.It allows a remote, local or automatic operation of the access control equipment which verifies and identifies all users entering the controlled areas.The global architecture of the LHC Access System is now designed and is being validated to ensure that it meets the safety requirements for operation of the LHC.A pilot installation will be tested in the summer 2005 to validate the concept with the us...

Access control and personal identification systems

CERN Document Server

Bowers, Dan M

1988-01-01

Access Control and Personal Identification Systems provides an education in the field of access control and personal identification systems, which is essential in selecting the appropriate equipment, dealing intelligently with vendors in purchases of the equipment, and integrating the equipment into a total effective system. Access control devices and systems comprise an important part of almost every security system, but are seldom the sole source of security. In order for the goals of the total system to be met, the other portions of the security system must also be well planned and executed

OGIS Access System

Data.gov (United States)

National Archives and Records Administration — The OGIS Access System (OAS) provides case management, stakeholder collaboration, and public communications activities including a web presence via a web portal.

Automated Computer Access Request System

Science.gov (United States)

Snook, Bryan E.

2010-01-01

The Automated Computer Access Request (AutoCAR) system is a Web-based account provisioning application that replaces the time-consuming paper-based computer-access request process at Johnson Space Center (JSC). Auto- CAR combines rules-based and role-based functionality in one application to provide a centralized system that is easily and widely accessible. The system features a work-flow engine that facilitates request routing, a user registration directory containing contact information and user metadata, an access request submission and tracking process, and a system administrator account management component. This provides full, end-to-end disposition approval chain accountability from the moment a request is submitted. By blending both rules-based and rolebased functionality, AutoCAR has the flexibility to route requests based on a user s nationality, JSC affiliation status, and other export-control requirements, while ensuring a user s request is addressed by either a primary or backup approver. All user accounts that are tracked in AutoCAR are recorded and mapped to the native operating system schema on the target platform where user accounts reside. This allows for future extensibility for supporting creation, deletion, and account management directly on the target platforms by way of AutoCAR. The system s directory-based lookup and day-today change analysis of directory information determines personnel moves, deletions, and additions, and automatically notifies a user via e-mail to revalidate his/her account access as a result of such changes. AutoCAR is a Microsoft classic active server page (ASP) application hosted on a Microsoft Internet Information Server (IIS).

Access control system for ISABELLE

International Nuclear Information System (INIS)

Potter, K.; Littenberg, L.

1977-01-01

An access system based on the one now in operation at the CERN ISR is recommended. Access doors would presumably be located at the entrances to the utility tunnels connecting the support buildings with the ring. Persons requesting access would insert an identity card into a scanner to activate the system. The request would be autologged, the keybank adjacent to the door would be unlocked and ISABELLE operations would be notified. The operator would then select the door, activating a TV-audio link. The person requesting entry would draw a key from the bank, show it and his film badge to the operator who would enable the door release

Easy Access: Auditing the System Network

Science.gov (United States)

Wiech, Dean

2013-01-01

In today's electronic learning environment, access to appropriate systems and data is of the utmost importance to students, faculty, and staff. Without proper access to the school's internal systems, teachers could be prevented from logging on to an online learning system and students might be unable to submit course work to an online…

LANSCE personnel access control system (PACS)

International Nuclear Information System (INIS)

Sturrock, J.C.; Gallegos, F.R.; Hall, M.J.

1997-01-01

The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. The Personnel Access Control System (PACS) is a component of the RSS that is designed to prevent personnel access to areas where prompt radiation is a hazard. PACS was designed to replace several older personnel safety systems (PSS) with a single modem unified design. Lessons learned from the operation over the last 20 years were incorporated into a redundant sensor, single-point failure safe, fault tolerant, and tamper-resistant system that prevents access to the beam areas by controlling the access keys and beam stoppers. PACS uses a layered philosophy to the physical and electronic design. The most critical assemblies are battery backed up, relay logic circuits; less critical devices use Programmable Logic Controllers (PLCs) for timing functions and communications. Outside reviewers have reviewed the operational safety of the design. The design philosophy, lessons learned, hardware design, software design, operation, and limitations of the device are described

Internet-accessible real-time weather information system

Digital Repository Service at National Institute of Oceanography (India)

Desai, R.G.P.; Joseph, A.; Desa, E.; Mehra, P.; Desa, E.; Gouveia, A.D.

An internet-accessible real-time weather information system has been developed. This system provides real-time accessibility to weather information from a multitude of spatially distributed weather stations. The Internet connectivity also offers...

Access Control Management for SCADA Systems

Science.gov (United States)

Hong, Seng-Phil; Ahn, Gail-Joon; Xu, Wenjuan

The information technology revolution has transformed all aspects of our society including critical infrastructures and led a significant shift from their old and disparate business models based on proprietary and legacy environments to more open and consolidated ones. Supervisory Control and Data Acquisition (SCADA) systems have been widely used not only for industrial processes but also for some experimental facilities. Due to the nature of open environments, managing SCADA systems should meet various security requirements since system administrators need to deal with a large number of entities and functions involved in critical infrastructures. In this paper, we identify necessary access control requirements in SCADA systems and articulate access control policies for the simulated SCADA systems. We also attempt to analyze and realize those requirements and policies in the context of role-based access control that is suitable for simplifying administrative tasks in large scale enterprises.

Computer access security code system

Science.gov (United States)

Collins, Earl R., Jr. (Inventor)

1990-01-01

A security code system for controlling access to computer and computer-controlled entry situations comprises a plurality of subsets of alpha-numeric characters disposed in random order in matrices of at least two dimensions forming theoretical rectangles, cubes, etc., such that when access is desired, at least one pair of previously unused character subsets not found in the same row or column of the matrix is chosen at random and transmitted by the computer. The proper response to gain access is transmittal of subsets which complete the rectangle, and/or a parallelepiped whose opposite corners were defined by first groups of code. Once used, subsets are not used again to absolutely defeat unauthorized access by eavesdropping, and the like.

AN OVERVIEW OF UMTS AND WIMAX NETWORKS INTEGRATION

Directory of Open Access Journals (Sweden)

Dewi Wirastuti

2010-12-01

Full Text Available This paper gives an overview of the network integration of UMTS (Universal Mobile TelecommunicationSystem with WiMAX (Wordwide Interoperability of Microwave Access. A few proposed interworking solutionsand seamless integration of both networks are explained. The best architecture and key procedures that will enablethe integration both networks and handover mechanism for the seamless mobility are presented. Considering thetrend of the current network evolution, which is the convergence between the telecommunications and broadcastworlds, an integration of mobile WiMAX with present 2G, 2.5G or 3G accesses into a homogeneous architecturegoes a long way to achieve the reality of mobile broadband networks. With the advent of mobile WiMAX, a mobilebroadband wireless access solution and based on all-IP (Internet Protocol based OFDMA (Orthogonal FrequencyDivision Multiple Access technology, an UMTS-WiMAX

Research of user access control for networked manufacturing system

Institute of Scientific and Technical Information of China (English)

ZHENG Xiao-lin; LEI Yu; CHEN De-ren

2006-01-01

An integrated user access control method was proposed to address the issues of security and management in networked manufacturing systems (NMS).Based on the analysis of the security issues in networked manufacturing system,an integrated user access control method composed of role-based access control (RBAC),task-based access control (TBAC),relationship-driven access control (RDAC)and coalition-based access control (CBAC) was proposed,including the hierarchical user relationship model,the reference model and the process model.The elements and their relationships were defined,and the expressions of constraints authorization were given.The extensible access control markup language (XACML) was used to implement this method.This method was used in the networked manufacturing system in the Shaoxing spinning region of China.The results show that the integrated user access control method can reduce the costs of system security maintenance and management.

Computer Security Systems Enable Access.

Science.gov (United States)

Riggen, Gary

1989-01-01

A good security system enables access and protects information from damage or tampering, but the most important aspects of a security system aren't technical. A security procedures manual addresses the human element of computer security. (MLW)

An Attribute Based Access Control Framework for Healthcare System

Science.gov (United States)

Afshar, Majid; Samet, Saeed; Hu, Ting

2018-01-01

Nowadays, access control is an indispensable part of the Personal Health Record and supplies for its confidentiality by enforcing policies and rules to ensure that only authorized users gain access to requested resources in the system. In other words, the access control means protecting patient privacy in healthcare systems. Attribute-Based Access Control (ABAC) is a new access control model that can be used instead of other traditional types of access control such as Discretionary Access Control, Mandatory Access Control, and Role-Based Access Control. During last five years ABAC has shown some applications in both recent academic fields and industry purposes. ABAC by using user’s attributes and resources, makes a decision according to an access request. In this paper, we propose an ABAC framework for healthcare system. We use the engine of ABAC for rendering and enforcing healthcare policies. Moreover, we handle emergency situations in this framework.

Experimental demonstration of high spectral efficient 4 × 4 MIMO SCMA-OFDM/OQAM radio over multi-core fiber system.

Science.gov (United States)

Liu, Chang; Deng, Lei; He, Jiale; Li, Di; Fu, Songnian; Tang, Ming; Cheng, Mengfan; Liu, Deming

2017-07-24

In this paper, 4 × 4 multiple-input multiple-output (MIMO) radio over 7-core fiber system based on sparse code multiple access (SCMA) and OFDM/OQAM techniques is proposed. No cyclic prefix (CP) is required by properly designing the prototype filters in OFDM/OQAM modulator, and non-orthogonally overlaid codewords by using SCMA is help to serve more users simultaneously under the condition of using equal number of time and frequency resources compared with OFDMA, resulting in the increase of spectral efficiency (SE) and system capacity. In our experiment, 11.04 Gb/s 4 × 4 MIMO SCMA-OFDM/OQAM signal is successfully transmitted over 20 km 7-core fiber and 0.4 m air distance in both uplink and downlink. As a comparison, 6.681 Gb/s traditional MIMO-OFDM signal with the same occupied bandwidth has been evaluated for both uplink and downlink transmission. The experimental results show that SE could be increased by 65.2% with no bit error rate (BER) performance degradation compared with the traditional MIMO-OFDM technique.

Joint time-frequency domain proportional fair scheduler with HARQ for 3GPP LTE systems

OpenAIRE

Beh, KC; Doufexi, A; Armour, SMD

2008-01-01

This paper explores the potential gain of joint diversity in both frequency domain and time domain which can be exploited to achieve spectral efficiency gains whilst simultaneously facilitating QoS/ fairness in an OFDMA system particularly in 3GPP Long Term Evolution (LTE)). The performance of several joint time-frequency schedulers is investigated. Simulation results show that joint time frequency schedulers achieve significantly superior performance compared to a more conventional time doma...

Information-flow-based Access Control for Virtualized Systems

Directory of Open Access Journals (Sweden)

Dmitriy Aleksandrovich Postoev

2014-12-01

Full Text Available The article is devoted to the method of information-flow-based access control, adopted for virtualized systems. General structure of access control system for virtual infrastructure is proposed.

Modeling and Mangement of InterCell Interference in Future Generation Wireless Networks

KAUST Repository

Tabassum, Hina

2012-12-01

There has been a rapid growth in the data rate carried by cellular services, and this increase along with the emergence of new multimedia applications have motivated the 3rd Generation Partnership (3GPP) Project to launch Long-Term Evolution (LTE) [1]. LTE is the latest standard in the mobile network technology and is designed to meet the ubiquitous demands of next-generation mobile networks. LTE assures significant spectral and energy efficiency gains in both the uplink and down- link with low latency. Multiple access schemes such as Orthogonal Frequency Division Aultiple Access (OFDMA) and Single Carrier Frequency Division Multiple Access (SC-FDMA) which is a modified version of OFDMA have been recently adopted in 3GPP LTE downlink and uplink, respectively [1]. A typical feature of OFDMA is the decomposition of available bandwidth into multiple narrow orthogonal subcarriers. The orthogonality among subcarriers causes minimal intra-cell interference, however, the inter-cell interference (ICI) incurred on a given subcarrier is relatively impulsive and poses a fundamental challenge for the network designers. Moreover, as the number of interferers on a given subcarrier can be relatively limited it may not be accurate to model ICI as a Gaussian random variable by invoking the central limit theorem. The nature of ICI relies on a variety of indeterministic parameters which include frequency reuse factor, channel conditions, scheduling decisions, transmit power, and location of the interferers. This thesis presents a combination of algorithmic and theoretical studies for efficient modeling and management of ICI via radio resource management. In the preliminary phase, we focus on developing and analyzing the performance of several centralized and distributed interference mitigation and rate maximization algorithms. These algorithms relies on optimizing the spectrum allocation and user’s transmission powers to maximize the system capacity. Even though, the developed

Multiuser Scheduling on the Downlink of an LTE Cellular System

Directory of Open Access Journals (Sweden)

Raymond Kwan

2008-01-01

Full Text Available The challenge of scheduling user transmissions on the downlink of a long-term evolution (LTE cellular communication system is addressed. In particular, a novel optimalmultiuser scheduler is proposed. Numerical results show that the system performance improves with increasing correlation among OFDMA subcarriers. It is found that only a limited amount of feedback information is needed to achieve relatively good performance. A suboptimal reduced-complexity scheduler is also proposed and shown to provide good performance. The suboptimal scheme is especially attractive when the number of users is large, in which case the complexity of the optimal scheme is high.

Nuclear information access system

International Nuclear Information System (INIS)

Ham, C. H.; Yang, M. H.; Yoon, S. W.

1998-01-01

The energy supply in the countries, which have abundant energy resources, may not be affected by accepting the assertion of anti-nuclear and environment groups. Anti-nuclear movements in the countries which have little energy resources may cause serious problem in securing energy supply. Especially, it is distinct in Korea because she heavily depends on nuclear energy in electricity supply(nuclear share in total electricity supply is about 40%).The cause of social trouble surrounding nuclear energy is being involved with various circumstances. However, it is very important that we are not aware of the importance of information access and prepared for such a situation from the early stage of nuclear energy's development. In those matter, this paper analyzes the contents of nuclear information access system in France and Japan which have dynamic nuclear development program and presents the direction of the nuclear access regime through comparing Korean status and referring to progresses of the regime

Role Based Access Control system in the ATLAS experiment

International Nuclear Information System (INIS)

Valsan, M L; Dumitru, I; Darlea, G L; Bujor, F; Dobson, M; Miotto, G Lehmann; Schlenker, S; Avolio, G; Scannicchio, D A; Filimonov, V; Khomoutnikov, V; Zaytsev, A S; Korol, A A; Bogdantchikov, A; Caramarcu, C; Ballestrero, S; Twomey, M

2011-01-01

The complexity of the ATLAS experiment motivated the deployment of an integrated Access Control System in order to guarantee safe and optimal access for a large number of users to the various software and hardware resources. Such an integrated system was foreseen since the design of the infrastructure and is now central to the operations model. In order to cope with the ever growing needs of restricting access to all resources used within the experiment, the Roles Based Access Control (RBAC) previously developed has been extended and improved. The paper starts with a short presentation of the RBAC design, implementation and the changes made to the system to allow the management and usage of roles to control access to the vast and diverse set of resources. The RBAC implementation uses a directory service based on Lightweight Directory Access Protocol to store the users (∼3000), roles (∼320), groups (∼80) and access policies. The information is kept in sync with various other databases and directory services: human resources, central CERN IT, CERN Active Directory and the Access Control Database used by DCS. The paper concludes with a detailed description of the integration across all areas of the system.

A study of Trade-off between Opportunistic Resource Allocation and Interference Alignment in Femtocell Scenarios

DEFF Research Database (Denmark)

Lertwiram, Namzilp; Popovski, Petar; Sakaguchi, Kei

2012-01-01

One of the main problems in wireless heterogeneous networks is interference between macro- and femto-cells. Using Orthogonal Frequency-Division Multiple Access (OFDMA) to create multiple frequency orthogonal sub-channels, this interference can be completely avoided if each sub-channel is exclusiv...... of the communication resources. In this letter we investigate the interactions and the trade-offs between these two strategies....

Role Based Access Control system in the ATLAS experiment

CERN Document Server

Valsan, M L; The ATLAS collaboration; Lehmann Miotto, G; Scannicchio, D A; Schlenker, S; Filimonov, V; Khomoutnikov, V; Dumitru, I; Zaytsev, A S; Korol, A A; Bogdantchikov, A; Caramarcu, C; Ballestrero, S; Darlea, G L; Twomey, M; Bujor, F; Avolio, G

2011-01-01

The complexity of the ATLAS experiment motivated the deployment of an integrated Access Control System in order to guarantee safe and optimal access for a large number of users to the various software and hardware resources. Such an integrated system was foreseen since the design of the infrastructure and is now central to the operations model. In order to cope with the ever growing needs of restricting access to all resources used within the experiment, the Roles Based Access Control (RBAC) previously developed has been extended and improved. The paper starts with a short presentation of the RBAC design, implementation and the changes made to the system to allow the management and usage of roles to control access to the vast and diverse set of resources. The paper continues with a detailed description of the integration across all areas of the system: local Linux and Windows nodes in the ATLAS Control Network (ATCN), the Linux application gateways offering remote access inside ATCN, the Windows Terminal Serv...

Role Based Access Control System in the ATLAS Experiment

CERN Document Server

Valsan, M L; The ATLAS collaboration; Lehmann Miotto, G; Scannicchio, D A; Schlenker, S; Filimonov, V; Khomoutnikov, V; Dumitru, I; Zaytsev, A S; Korol, A A; Bogdantchikov, A; Avolio, G; Caramarcu, C; Ballestrero, S; Darlea, G L; Twomey, M; Bujor, F

2010-01-01

The complexity of the ATLAS experiment motivated the deployment of an integrated Access Control System in order to guarantee safe and optimal access for a large number of users to the various software and hardware resources. Such an integrated system was foreseen since the design of the infrastructure and is now central to the operations model. In order to cope with the ever growing needs of restricting access to all resources used within the experiment, the Roles Based Access Control (RBAC) previously developed has been extended and improved. The paper starts with a short presentation of the RBAC design, implementation and the changes made to the system to allow the management and usage of roles to control access to the vast and diverse set of resources. The paper continues with a detailed description of the integration across all areas of the system: local Linux and Windows nodes in the ATLAS Control Network (ATCN), the Linux application gateways offering remote access inside ATCN, the Windows Terminal Serv...

A simple carrier frequency offset synchronization strategy for multiple relay cooperative diversity ofdm system

International Nuclear Information System (INIS)

Mudassar, I.; Cheema, A.; Shoab, A.

2014-01-01

Cooperative Diversity Orthogonal Frequency Division Modulation (CD-OFDM) systems are very sensitive to synchronization errors. In CD-OFDM, synchronization is more complex because all cooperative nodes (CNs) have their own frequency oscillator and different channel path which results in different timing and carrier frequency offset (CFO) for each node. Consequently, each node has to be synchronized separately without affecting the synchronization process of other nodes. All CNs transmit simultaneously during cooperation phase (C-phase) and their aggregate signal is received at the destination node. A unique frequency domain (FD) preamble is proposed for each CN during C-phase that will allow simple separation of cooperative nodes. These FD multiplexed preambles make the synchronization problem identical to OFDMA uplink. OFDMA system typically uses highly complex iterative CFO estimators for uplink synchronization. However, a simple one-shot CFO estimator is proposed that uses repeated preamble of two OFDM symbol duration. The proposed method is computationally efficient because it relies on FFT operation for user separation and interference mitigation. Subsequently, time domain (TD) multiplication is used for CFO correction of each CN. Furthermore, a CD-OFDM protocol for data transmission is presented that suites the proposed estimator and harnesses spatial diversity. The proposed estimator shows good statistical results during simulations in AWGN and Rayleigh environments. During evaluation, estimator variance, mean square error and symbol error rate are used as performance measure. (author)

Chunk-Based Energy Efficient Resource Allocation in OFDMA Systems

Directory of Open Access Journals (Sweden)

Yong Li

2013-01-01

Full Text Available Energy efficiency (EE capacity analysis of the chunk-based resource allocation is presented by considering the minimum spectrum efficiency (SE constraint in downlink multiuser orthogonal frequency division multiplexing (OFDM systems. Considering the minimum SE requirement, an optimization problem to maximize EE with limited transmit power is formulated over frequency selective channels. Based on this model, a low-complexity energy efficient resource allocation is proposed. The effects of system parameters, such as the average channel gain-to-noise ratio (CNR and the number of subcarriers per chunk, are evaluated. Numerical results demonstrate the effectiveness of the proposed scheme for balancing the EE and SE.

Analysis of Access Control Policies in Operating Systems

Science.gov (United States)

Chen, Hong

2009-01-01

Operating systems rely heavily on access control mechanisms to achieve security goals and defend against remote and local attacks. The complexities of modern access control mechanisms and the scale of policy configurations are often overwhelming to system administrators and software developers. Therefore, mis-configurations are common, and the…

Performance estimates for personnel access control systems

International Nuclear Information System (INIS)

Bradley, R.G.

1980-10-01

Current performance estimates for personnel access control systems use estimates of Type I and Type II verification errors. A system performance equation which addresses normal operation, the insider, and outside adversary attack is developed. Examination of this equation reveals the inadequacy of classical Type I and II error evaluations which require detailed knowledge of the adversary threat scenario for each specific installation. Consequently, new performance measures which are consistent with the performance equation and independent of the threat are developed as an aid in selecting personnel access control systems

Access control within military C4ISR systems

Science.gov (United States)

Maschino, Mike

2003-07-01

Command, Control, Communications, Computers, Intelligence, Surveillance and Reconnaissance (C4ISR) tactical battlefield systems must provide the right information and resources to the right individuals at the right time. At the same time, the C4ISR system must enforce access controls to prevent the wrong individuals from obtaining sensitive information, or consuming scarce resources. Because lives, missions and property depend upon them, these access control mechanisms must be effective, reliable, efficient and flexible. The mechanisms employed must suit the nature of the items that are to be protected, as well as the varieties of access policies that must be enforced, and the types of access that will be made to these items. Some access control technologies are inherently centralized, while others are suitable for distributed implementation. The C4ISR architect must select from among the available technologies a combination of mechanisms that eases the burden of policy administration, but is inherently survivable, accurate, resource efficient, and which provides low latency. This paper explores various alternative access enforcement mechanisms, and assesses their effectiveness in managing policy-driven access control within the battlespace.

Safety testing for LHC access system

CERN Document Server

Valentini, F; Ninin, P; Scibile, S

2008-01-01

In the domain of Safety Real-Time Systems the problem of testing represents always a big effort in terms of time, costs and efficiency to guarantee an adequate coverage degree. Exhaustive tests may, in fact, not be practicable for large and distributed systems. This paper describes the testing process followed during the validation of the CERN's LHC Access System [1], responsible for monitoring and preventing physical risks for the personnel accessing the underground areas. In the paper we also present a novel strategy for the testing problem, intended to drastically reduce the time for the test patterns generation and execution. In particular, we propose a methodology for blackbox testing that relies on the application of Model Checking techniques. Model Checking is a formal method from computer science, commonly adopted to prove correctness of system’s models through an automatic system’s state space exploration against some property formulas.

Location-based resource allocation for OFDMA cognitive radio systems

KAUST Repository

Nam, Haewoon; Ben Ghorbel, Mahdi; Alouini, Mohamed-Slim

2010-01-01

In cognitive radio systems, in order for the secondary users to opportunistically share the spectrum without interfering the primary users, an accurate spectrum measurement and a precise estimation of the interference at the primary users

Effect Through Broadcasting System Access Point For Video Transmission

Directory of Open Access Journals (Sweden)

Leni Marlina

2015-08-01

Full Text Available Most universities are already implementing wired and wireless network that is used to access integrated information systems and the Internet. At present it is important to do research on the influence of the broadcasting system through the access point for video transmitter learning in the university area. At every university computer network through the access point must also use the cable in its implementation. These networks require cables that will connect and transmit data from one computer to another computer. While wireless networks of computers connected through radio waves. This research will be a test or assessment of how the influence of the network using the WLAN access point for video broadcasting means learning from the server to the client. Instructional video broadcasting from the server to the client via the access point will be used for video broadcasting means of learning. This study aims to understand how to build a wireless network by using an access point. It also builds a computer server as instructional videos supporting software that can be used for video server that will be emitted by broadcasting via the access point and establish a system of transmitting video from the server to the client via the access point.

Access safety systems - New concepts from the LHC experience

International Nuclear Information System (INIS)

Ladzinski, T.; Delamare, C.; Luca, S. di; Hakulinen, T.; Hammouti, L.; Havart, F.; Juget, J.F.; Ninin, P.; Nunes, R.; Riesco, T.; Sanchez-Corral Mena, E.; Valentini, F.

2012-01-01

The LHC Access Safety System has introduced a number of new concepts into the domain of personnel protection at CERN. These can be grouped into several categories: organisational, architectural and concerning the end-user experience. By anchoring the project on the solid foundations of the IEC 61508/61511 methodology, the CERN team and its contractors managed to design, develop, test and commission on time a SIL3 safety system. The system uses a successful combination of the latest Siemens redundant safety programmable logic controllers with a traditional relay logic hard wired loop. The external envelope barriers used in the LHC include personnel and material access devices, which are interlocked door-booths introducing increased automation of individual access control, thus removing the strain from the operators. These devices ensure the inviolability of the controlled zones by users not holding the required credentials. To this end they are equipped with personnel presence detectors and the access control includes a state of the art bio-metry check. Building on the LHC experience, new projects targeting the refurbishment of the existing access safety infrastructure in the injector chain have started. This paper summarises the new concepts introduced in the LHC access control and safety systems, discusses the return of experience and outlines the main guiding principles for the renewal stage of the personnel protection systems in the LHC injector chain in a homogeneous manner. (authors)

Task-role-based Access Control Model in Smart Health-care System

Directory of Open Access Journals (Sweden)

Wang Peng

2015-01-01

Full Text Available As the development of computer science and smart health-care technology, there is a trend for patients to enjoy medical care at home. Taking enormous users in the Smart Health-care System into consideration, access control is an important issue. Traditional access control models, discretionary access control, mandatory access control, and role-based access control, do not properly reflect the characteristics of Smart Health-care System. This paper proposes an advanced access control model for the medical health-care environment, task-role-based access control model, which overcomes the disadvantages of traditional access control models. The task-role-based access control (T-RBAC model introduces a task concept, dividing tasks into four categories. It also supports supervision role hierarchy. T-RBAC is a proper access control model for Smart Health-care System, and it improves the management of access rights. This paper also proposes an implementation of T-RBAC, a binary two-key-lock pair access control scheme using prime factorization.

Task Delegation Based Access Control Models for Workflow Systems

Science.gov (United States)

Gaaloul, Khaled; Charoy, François

e-Government organisations are facilitated and conducted using workflow management systems. Role-based access control (RBAC) is recognised as an efficient access control model for large organisations. The application of RBAC in workflow systems cannot, however, grant permissions to users dynamically while business processes are being executed. We currently observe a move away from predefined strict workflow modelling towards approaches supporting flexibility on the organisational level. One specific approach is that of task delegation. Task delegation is a mechanism that supports organisational flexibility, and ensures delegation of authority in access control systems. In this paper, we propose a Task-oriented Access Control (TAC) model based on RBAC to address these requirements. We aim to reason about task from organisational perspectives and resources perspectives to analyse and specify authorisation constraints. Moreover, we present a fine grained access control protocol to support delegation based on the TAC model.

QoS-Guaranteed Admission Control for OFDMA-based Systems

DEFF Research Database (Denmark)

Ramkumar, Venkata; Anggorojati, Bayu; Lucian, Stefan P. Andrei

2010-01-01

This paper proposes a novel admission control (AC) algorithm for guaranteed quality of service (QoS) to all users. The proposed solution provides better utilization of system capacity using adaptive modulation (AM). A scheduler based on a per user priority function is also given in this paper. Th...

Integrated Identity and Access Management System for Tertiary ...

African Journals Online (AJOL)

Nigerian Journal of Technology ... identity management and access control and the unavailability of actionable information on pattern of ... This Tertiary Identity and Access Management System (T-IAMS) is a fingerprint biometric database that ...

Task-role-based Access Control Model in Smart Health-care System

OpenAIRE

Wang Peng; Jiang Lingyun

2015-01-01

As the development of computer science and smart health-care technology, there is a trend for patients to enjoy medical care at home. Taking enormous users in the Smart Health-care System into consideration, access control is an important issue. Traditional access control models, discretionary access control, mandatory access control, and role-based access control, do not properly reflect the characteristics of Smart Health-care System. This paper proposes an advanced access control model for...

H1DS: A new web-based data access system

Energy Technology Data Exchange (ETDEWEB)

Pretty, D.G., E-mail: david.pretty@anu.edu.au; Blackwell, B.D.

2014-05-15

Highlights: • We present H1DS, a new RESTful web service for accessing fusion data. • We examine the scalability and extensibility of H1DS. • We present a fast and user friendly web browser client for the H1DS web service. • A summary relational database is presented as an application of the H1DS API. - Abstract: A new data access system, H1DS, has been developed and deployed for the H-1 Heliac at the Australian Plasma Fusion Research Facility. The data system provides access to fusion data via a RESTful web service. With the URL acting as the API to the data system, H1DS provides a scalable and extensible framework which is intuitive to new users, and allows access from any internet connected device. The H1DS framework, originally designed to work with MDSplus, has a modular design which can be extended to provide access to alternative data storage systems.

H1DS: A new web-based data access system

International Nuclear Information System (INIS)

Pretty, D.G.; Blackwell, B.D.

2014-01-01

Highlights: • We present H1DS, a new RESTful web service for accessing fusion data. • We examine the scalability and extensibility of H1DS. • We present a fast and user friendly web browser client for the H1DS web service. • A summary relational database is presented as an application of the H1DS API. - Abstract: A new data access system, H1DS, has been developed and deployed for the H-1 Heliac at the Australian Plasma Fusion Research Facility. The data system provides access to fusion data via a RESTful web service. With the URL acting as the API to the data system, H1DS provides a scalable and extensible framework which is intuitive to new users, and allows access from any internet connected device. The H1DS framework, originally designed to work with MDSplus, has a modular design which can be extended to provide access to alternative data storage systems

Human engineering considerations in designing a computerized controlled access security system

International Nuclear Information System (INIS)

Moore, J.W.; Banks, W.W.

1988-01-01

This paper describes a human engineering effort in the design of a major security system upgrade at Lawrence Livermore National Laboratory. This upgrade was to be accomplished by replacing obsolete and difficult-to-man (i.e., multiple operator task actions required) security equipment and systems with a new, automated, computer-based access control system. The initial task was to assist the electronic and mechanical engineering staff in designing a computerized security access system too functionally and ergonomically accommodate 100% of the Laboratory user population. The new computerized access system was intended to control entry into sensitive exclusion areas by requiring personnel to use an entry booth-based system and/or a remote access control panel system. The primary user interface with the system was through a control panel containing a magnetic card reader, function buttons, LCD display, and push-button keypad

The promise of downlink MU-MIMO for high-capacity next generation mobile broadband networks based on IEEE 802.16 m

OpenAIRE

Papathanassiou Apostolos; Davydov Alexei

2011-01-01

Abstract The dramatic increase of the demand for mobile broadband services poses stringent requirements on the performance evolution of currently deployed mobile broadband networks, such as Mobile WiMAX Release 1 and 3GPP LTE Release 8. Although the combination of single-user multiple-input multiple-output (SU-MIMO) and orthogonal frequency division multiple access (OFDMA) provide the appropriate technologies for improving the downlink performance of third generation (3G) code division multip...

A utility perspective on radiation worker access control systems

International Nuclear Information System (INIS)

Watson, B.A.; Goff, T.E.

1984-01-01

Based on an evaluation of the current commercial Radiation Worker Access Control Software Systems, Baltimore Gas and Electric Company has elected to design and develop a site specific access control and accountability system for the Calvert Cliffs Nuclear Power Plant. The vendor provided systems allow for radiation worker access control based on training and external exposure records and authorizations. These systems do not afford internal exposure control until after bioassay measurements or maximum permissible concentration-hours are tabulated. The vendor provided systems allow for data trending for ALARA purposes, but each software package must be modified to meet site specific requirements. Unlike the commercial systems, the Calvert Cliffs Radiological Controls and Accountability System (RCAS) will provide radiation worker exposure control, both internal and external. The RCAS is designed to fulfill the requirements by integrating the existing Radiation Safety, Dosemetry, and Training data bases with a comprehensive radiological surveillance program. Prior to each worker's entry into the Radiological Control Area; his training and qualifications, radiation exposure history and authorization, will be compared with administrative controls, such as radiation work permits, and respiratory protection requirements and the radiological conditions in the work area. The RCAS, a computer based applied health physics access control system is described as it is presently configured for development. The mechanisms for enhancing worker internal and external exposure controls are discussed. Proposed data application to both the Calvert Cliffs ALARA and outage planning programs is included

The ARAC client system: network-based access to ARAC

International Nuclear Information System (INIS)

Leach, M J; Sumikawa, D; Webster, C

1999-01-01

The ARAC Client System allows users (such as emergency managers and first responders) with commonly available desktop and laptop computers to utilize the central ARAC system over the Internet or any other communications link using Internet protocols. Providing cost-effective fast access to the central ARAC system greatly expands the availability of the ARAC capability. The ARAC Client system consists of (1) local client applications running on the remote user's computer, and (2) ''site servers'' that provide secure access to selected central ARAC system capabilities and run on a scalable number of dedicated workstations residing at the central facility. The remote client applications allow users to describe a real or potential them-bio event, electronically sends this information to the central ARAC system which performs model calculations, and quickly receive and visualize the resulting graphical products. The site servers will support simultaneous access to ARAC capabilities by multiple users. The ARAC Client system is based on object-oriented client/server and distributed computing technologies using CORBA and Java, and consists of a large number of interacting components

Channel Access Algorithm Design for Automatic Identification System

Institute of Scientific and Technical Information of China (English)

Oh Sang-heon; Kim Seung-pum; Hwang Dong-hwan; Park Chan-sik; Lee Sang-jeong

2003-01-01

The Automatic Identification System (AIS) is a maritime equipment to allow an efficient exchange of the navigational data between ships and between ships and shore stations. It utilizes a channel access algorithm which can quickly resolve conflicts without any intervention from control stations. In this paper, a design of channel access algorithm for the AIS is presented. The input/output relationship of each access algorithm module is defined by drawing the state transition diagram, dataflow diagram and flowchart based on the technical standard, ITU-R M.1371. In order to verify the designed channel access algorithm, the simulator was developed using the C/C++ programming language. The results show that the proposed channel access algorithm can properly allocate transmission slots and meet the operational performance requirements specified by the technical standard.

Development of an access control system for the LHD experimental hall

International Nuclear Information System (INIS)

Kawano, T.; Inoue, N.; Sakuma, Y.; Uda, T.; Yamanishi, H.; Miyake, H.; Tanahashi, S.; Motozima, O.

2000-01-01

An access control system for the LHD (Large Helical Device) experimental hall had been constructed and its practical operation started in March 1998. Continuously, the system has been improved. The present system keeps watch on involved entrance and exit for the use of persons at four entrances by using five turnstile gates while watching on eight shielding doors at eight positions (four entrances, three carriage entrances and a hall overview) and a stairway connecting the LHD main hall with the LHD basement. Besides, for the security of safety operation of the LHD, fifteen kinds of interlock signals are exchanged between the access control system and the LHD control system. Seven of the interlock signals are properly sent as the occasional demands from the access control system to the LHD control system, in which three staple signals are B Personnel Access to Controlled Area, D Shielding Door Closed, and E No Entrance. It is important that any plasma experiments of the LHD are not permitted while the signal B being sent or D being not sent. The signal E is sent to inform the LHD control system that the turnstile gates are locked. All the plasma experiments should not be done unless the lock procedure of the turnstile is confirmed. When the turnstile gates are locked, any persons cannot enter into the LHD controlled area, but are permissible to exit only. Six of the interlock signals are used to send the information of the working at that time in the LHD controlled area to the access control system. When one signal of the operation mode is sent to the access control system from the LHD, the access control system sets the turnstile gate in situation corresponding to the operation mode, A Equipment Operation, B Vacuum Pumping, C Coil Cooling, D Coil Excitation, and E Plasma Experiment. If the access control system receives, for example, the signal B, this system sets the turnstile gate in the condition of control such that only persons assigned to the work of vacuum

Database design for Physical Access Control System for nuclear facilities

Energy Technology Data Exchange (ETDEWEB)

Sathishkumar, T., E-mail: satishkumart@igcar.gov.in; Rao, G. Prabhakara, E-mail: prg@igcar.gov.in; Arumugam, P., E-mail: aarmu@igcar.gov.in

2016-08-15

Highlights: • Database design needs to be optimized and highly efficient for real time operation. • It requires a many-to-many mapping between Employee table and Doors table. • This mapping typically contain thousands of records and redundant data. • Proposed novel database design reduces the redundancy and provides abstraction. • This design is incorporated with the access control system developed in-house. - Abstract: A (Radio Frequency IDentification) RFID cum Biometric based two level Access Control System (ACS) was designed and developed for providing access to vital areas of nuclear facilities. The system has got both hardware [Access controller] and software components [server application, the database and the web client software]. The database design proposed, enables grouping of the employees based on the hierarchy of the organization and the grouping of the doors based on Access Zones (AZ). This design also illustrates the mapping between the Employee Groups (EG) and AZ. By following this approach in database design, a higher level view can be presented to the system administrator abstracting the inner details of the individual entities and doors. This paper describes the novel approach carried out in designing the database of the ACS.

Database design for Physical Access Control System for nuclear facilities

International Nuclear Information System (INIS)

Sathishkumar, T.; Rao, G. Prabhakara; Arumugam, P.

2016-01-01

Highlights: • Database design needs to be optimized and highly efficient for real time operation. • It requires a many-to-many mapping between Employee table and Doors table. • This mapping typically contain thousands of records and redundant data. • Proposed novel database design reduces the redundancy and provides abstraction. • This design is incorporated with the access control system developed in-house. - Abstract: A (Radio Frequency IDentification) RFID cum Biometric based two level Access Control System (ACS) was designed and developed for providing access to vital areas of nuclear facilities. The system has got both hardware [Access controller] and software components [server application, the database and the web client software]. The database design proposed, enables grouping of the employees based on the hierarchy of the organization and the grouping of the doors based on Access Zones (AZ). This design also illustrates the mapping between the Employee Groups (EG) and AZ. By following this approach in database design, a higher level view can be presented to the system administrator abstracting the inner details of the individual entities and doors. This paper describes the novel approach carried out in designing the database of the ACS.

40 CFR 264.34 - Access to communications or alarm system.

Science.gov (United States)

2010-07-01

... FACILITIES Preparedness and Prevention § 264.34 Access to communications or alarm system. (a) Whenever... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Access to communications or alarm system. 264.34 Section 264.34 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID...

Generalized location-based resource allocation for OFDMA cognitive radio systems

KAUST Repository

Ben Ghorbel, Mahdi; Nam, Haewoon; Alouini, Mohamed-Slim

2010-01-01

Cognitive radio is one of the hot topics for emerging and future wireless communication. Cognitive users can share channels with primary users under the condition of non interference. In order to compute this interference, the cognitive system

Need an Information Security in Access Control System?

Directory of Open Access Journals (Sweden)

V. R. Petrov

2011-12-01

Full Text Available The purpose of this paper is the general problems of information security in access control system. The field of using is the in project of reconstruction Physical protection system.

RFID Based Security Access Control System with GSM Technology

OpenAIRE

Peter Adole; Joseph M. Môm; Gabriel A. Igwue

2016-01-01

The security challenges being encountered in many places today require electronic means of controlling access to secured premises in addition to the available security personnel. Various technologies were used in different forms to solve these challenges. The Radio Frequency Identification (RFID) Based Access Control Security system with GSM technology presented in this work helps to prevent unauthorized access to controlled environments (secured premises). This is achieved mainly...

A Fine-Grained Data Access Control System in Wireless Sensor Network

Directory of Open Access Journals (Sweden)

Boniface K. Alese

2015-12-01

Full Text Available The evolving realities of Wireless Sensor Network (WSN deployed to various terrain of life require serving multiple applications. As large amount of sensed data are distributed and stored in individual sensors nodes, the illegal access to these sensitive data can be devastating. Consequently, data insecurity becomes a big concern. This study, therefore, proposes a fine-grained access control system which only requires the right set of users to access a particular data, based on their access privileges in the sensor networks. It is designed using Priccess Protocol with Access policy formulation adopting the principle of Bell Lapadula model as well as Attribute-Based Encryption (ABE to control access to sensor data. The functionality of the proposed system is simulated using Netbeans. The performance analysis of the proposed system using execution time and size of the key show that the higher the key size, the harder it becomes for the attacker to hack the system. Additionally, the time taken for the proposed work is lesser which makes the work faster than the existing work. Consequently, a well secure interactive web-based application that could facilitates the field officers access to stored data in safe and secure manner is developed.

CDC STATE System Tobacco Legislation - Youth Access

Data.gov (United States)

U.S. Department of Health & Human Services — 1995-2018. Centers for Disease Control and Prevention (CDC). State Tobacco Activities Tracking and Evaluation (STATE) System. Legislation—Youth Access. The STATE...

Mitigation of MIMO Co-Channel Interference using robust interference cancellation receiver

DEFF Research Database (Denmark)

Rahman, Muhammad Imadur; De Carvalho, Elisabeth; Prasad, Ramjee

2007-01-01

(STBC) link may become equivalent to an interfering Spatial Multiplexing (SM) link. Using this knowledge and understanding, we propose an interference cancellation receiver robust to different types of MIMO interferers at cell edge for the Downlink (DL) of cellular systems. The receiver systematically...... performs a multiple symbol processing: this is the appropriate processing when the signal of interest or the signal of interferer is correlated across symbols, which is the case for STBC transmission. We evaluated different link combinations in terms of Signal to Interference and Noise Ratio (SINR......) statistics and Bit Error Rate (BER) performance in cellular Orthogonal Frequency Division Multiple Access (OFDMA) systems. We have found that the proposed multiple-symbol linear interference cancellation receiver performs satisfactorily when any kind of single 'logical' stream MIMO scheme is present...

Towards ubiquitous access of computer-assisted surgery systems.

Science.gov (United States)

Liu, Hui; Lufei, Hanping; Shi, Weishong; Chaudhary, Vipin

2006-01-01

Traditional stand-alone computer-assisted surgery (CAS) systems impede the ubiquitous and simultaneous access by multiple users. With advances in computing and networking technologies, ubiquitous access to CAS systems becomes possible and promising. Based on our preliminary work, CASMIL, a stand-alone CAS server developed at Wayne State University, we propose a novel mobile CAS system, UbiCAS, which allows surgeons to retrieve, review and interpret multimodal medical images, and to perform some critical neurosurgical procedures on heterogeneous devices from anywhere at anytime. Furthermore, various optimization techniques, including caching, prefetching, pseudo-streaming-model, and compression, are used to guarantee the QoS of the UbiCAS system. UbiCAS enables doctors at remote locations to actively participate remote surgeries, share patient information in real time before, during, and after the surgery.

Free-space optical code-division multiple-access system design

Science.gov (United States)

Jeromin, Lori L.; Kaufmann, John E.; Bucher, Edward A.

1993-08-01

This paper describes an optical direct-detection multiple access communications system for free-space satellite networks utilizing code-division multiple-access (CDMA) and forward error correction (FEC) coding. System performance is characterized by how many simultaneous users operating at data rate R can be accommodated in a signaling bandwidth W. The performance of two CDMA schemes, optical orthogonal codes (OOC) with FEC and orthogonal convolutional codes (OCC), is calculated and compared to information-theoretic capacity bounds. The calculations include the effects of background and detector noise as well as nonzero transmitter extinction ratio and power imbalance among users. A system design for 10 kbps multiple-access communications between low-earth orbit satellites is given. With near- term receiver technology and representative system losses, a 15 W peak-power transmitter provides 10-6 BER performance with seven interfering users and full moon background in the receiver FOV. The receiver employs an array of discrete wide-area avalanche photodiodes (APD) for wide field of view coverage. Issues of user acquisition and synchronization, implementation technology, and system scalability are also discussed.

ACCESS TO A COMPUTER SYSTEM. BETWEEN LEGAL PROVISIONS AND TECHNICAL REALITY

Directory of Open Access Journals (Sweden)

Maxim DOBRINOIU

2016-05-01

Full Text Available Nowadays, on a rise of cybersecurity incidents and a very complex IT&C environment, the national legal systems must adapt in order to properly address the new and modern forms of criminality in cyberspace. The illegal access to a computer system remains one of the most important cyber-related crimes due to its popularity but also from the perspective as being a door opened to computer data and sometimes a vehicle for other tech crimes. In the same time, the information society services slightly changed the IT paradigm and represent the new interface between users and systems. Is true that services rely on computer systems, but accessing services goes now beyond the simple accessing computer systems as commonly understood by most of the legislations. The article intends to explain other sides of the access related to computer systems and services, with the purpose to advance possible legal solutions to certain case scenarios.

The entire network topology display system of terminal communication access network

OpenAIRE

An Yi

2016-01-01

Now order terminal communication access network is network technology in Shanxi Province is diversiform, device type complex, lack of unified technical standard, the terminal communication access network management system of construction constitutes a great obstacle. Need to build a “unified communication interface and communication standard, unified communications network management” of the terminal communication access network cut in the integrated network management system, for the termina...

The COROT ground-based archive and access system

Science.gov (United States)

Solano, E.; González-Riestra, R.; Catala, C.; Baglin, A.

2002-01-01

A prototype of the COROT ground-based archive and access system is presented here. The system has been developed at LAEFF and it is based on the experience gained at Laboratorio de Astrofisica Espacial y Fisica Fundamental (LAEFF) with the INES (IUE Newly Extracted System) Archive.

CDC STATE System Tobacco Legislation - Youth Access

Data.gov (United States)

U.S. Department of Health & Human Services — 1995-2016. Centers for Disease Control and Prevention (CDC). State Tobacco Activities Tracking and Evaluation (STATE) System. Legislation—Youth Access. The STATE...

MAST's Integrated Data Access Management system: IDAM

International Nuclear Information System (INIS)

Muir, D.G.; Appel, L.; Conway, N.J.; Kirk, A.; Martin, R.; Meyer, H.; Storrs, J.; Taylor, D.; Thomas-Davies, N.; Waterhouse, J.

2008-01-01

A new Integrated Data Access Management system, IDAM, has been created to address specific data management issues of the MAST spherical Tokamak. For example, this system enables access to numerous file formats, both legacy and modern (IDA, Ufile, netCDF, HDF5, MDSPlus, PPF, JPF). It adds data quality values at the signal level, and automatically corrects for problems in data: in timings, calibrations, and labelling. It also builds new signals from signal components. The IDAM data server uses a hybrid XML-relational database to record how data are accessed, whether locally or remotely, and how alias and generic signal names are mapped to true names. Also, XML documents are used to encode the details of data corrections, as well as definitions of composite signals and error models. The simple, user friendly, API and accessor function library, written in C on Linux, is available for applications in C, C++, IDL and Fortran-90/95/2003 with good performance: a MAST plasma current trace (28 kbytes of data), requested using a generic name and with data corrections applied, is delivered over a 100 Mbit/s network in ∼13 ms

Distributed Access View Integrated Database (DAVID) system

Science.gov (United States)

Jacobs, Barry E.

1991-01-01

The Distributed Access View Integrated Database (DAVID) System, which was adopted by the Astrophysics Division for their Astrophysics Data System, is a solution to the system heterogeneity problem. The heterogeneous components of the Astrophysics problem is outlined. The Library and Library Consortium levels of the DAVID approach are described. The 'books' and 'kits' level is discussed. The Universal Object Typer Management System level is described. The relation of the DAVID project with the Small Business Innovative Research (SBIR) program is explained.

Optimizing data access in the LAMPF control system

International Nuclear Information System (INIS)

Schaller, S.C.; Corley, J.K.; Rose, P.A.

1985-01-01

The LAMPF control system data access software offers considerable power and flexibility to application programs through symbolic device naming and an emphasis on hardware independence. This paper discusses optimizations aimed at improving the performance of the data access software while retaining these capabilities. The only aspects of the optimizations visible to the application programs are ''vector devices'' and ''aggregate devices.'' A vector device accesses a set of hardware related data items through a single device name. Aggregate devices allow run-time optimization of references to groups of unrelated devices. Optimizations not visible on the application level include careful handling of: network message traffic; the sharing of global resources; and storage allocation

Location-Based Resource Allocation for OFDMA Cognitive Radio Systems

KAUST Repository

Ghorbel, Mahdi

2011-05-01

Cognitive radio is one of the hot topics for emerging and future wireless communication. It has been proposed as a suitable solution for the spectrum scarcity caused by the increase in frequency demand. The concept is based on allowing unlicensed users, called cognitive or secondary users, to share the unoccupied frequency bands with their owners, called the primary users, under constraints on the interference they cause to them. In order to estimate this interference, the cognitive system usually uses the channel state information to the primary user, which is often impractical to obtain. However, we propose to use location information, which is easier to obtain, to estimate this interference. The purpose of this work is to propose a subchannel and power allocation method which maximizes the secondary users\\' total capacity under the constraints of limited budget power and total interference to the primary under certain threshold. We model the problem as a constrained optimization problem for both downlink and uplink cases. Then, we propose low-complexity resource allocation schemes based on the waterfilling algorithm. The simulation results show the efficiency of the proposed method with comparison to the exhaustive search algorithm.

Hierarchical Downlink Resource Management Framework for OFDMA based WiMAX Systems

DEFF Research Database (Denmark)

Wang, Hua; Iversen, Villy Bæk

2008-01-01

IEEE 802.16, known as WiMAX, has received much attention for its capability to support multiple types of applications with diverse QoS requirements. Beyond what the standard has defined, radio resource management (RRM) still remains an open issue. In this paper, we propose a hierarchical downlink...... belonging to different service classes with the objective of increasing the spectral efficiency while satisfying the diverse QoS requirements in each service class. CAC highlights how to limit the number of ongoing connections preventing the system capacity from being overused. Through system...

Access control system for two person rule at Rokkasho Reprocessing Plant

International Nuclear Information System (INIS)

Yanagisawa, Sawako; Ino, Munekazu; Yamada, Noriyuki; Oota, Hiroto; Iwasaki, Mitsuaki; Kodani, Yoshiki; Iwamoto, Tomonori

2014-01-01

Following the amendment and enforcement of Regulation of Reprocessing Activity on March 29th 2012, two person rule has become compulsory for the specific rooms to counter and prevent the sabotage or theft of nuclear materials by the insiders at reprocessing plant in Japan. The rooms will include those which contains cooling systems for decay heat removal from spent fuels and so on, scavenging systems to prevent the hydrogen accumulation, and those which contains nuclear material. To ensure the two person rule at Rokkasho Reprocessing Plant, JNFL has recently, after comprehensive study, introduced efficient and effective access control system for the rooms mentioned above. The system is composed of bio-attestation devices, surveillance cameras and electronic locks to establish access control system. This report outlines the access control system for two person rule and introduces the operation. (author)

Efficient medium access control protocol for geostationary satellite systems

Institute of Scientific and Technical Information of China (English)

王丽娜; 顾学迈

2004-01-01

This paper proposes an efficient medium access control (MAC) protocol based on multifrequency-time division multiple access (MF-TDMA) for geostationary satellite systems deploying multiple spot-beams and onboard processing,which uses a method of random reservation access with movable boundaries to dynamically request the transmission slots and can transmit different types of traffic. The simulation results have shown that our designed MAC protocol can achieve a high bandwidth utilization, while providing the required quality of service (QoS) for each class of service.

A novel IPTV program multiplex access system to EPON

Science.gov (United States)

Xu, Xian; Liu, Deming; He, Wei; Lu, Xi

2007-11-01

With the rapid development of high speed networks, such as Ethernet Passive Optical Network (EPON), traffic patterns in access networks have evolved from traditional text-oriented service to the mixed text-, voice- and video- based services, leading to so called "Triple Play". For supporting IPTV service in EPON access network infrastructure, in this article we propose a novel IPTV program multiplex access system to EPON, which enables multiple IPTV program source servers to seamlessly access to IPTV service access port of optical line terminal (OLT) in EPON. There are two multiplex schemes, namely static multiplex scheme and dynamic multiplex scheme, in implementing the program multiplexing. Static multiplex scheme is to multiplex all the IPTV programs and forward them to the OLT, regardless of the need of end-users. While dynamic multiplex scheme can dynamically multiplex and forward IPTV programs according to what the end-users actually demand and those watched by no end-user would not be multiplexed. By comparing these two schemes, a reduced traffic of EPON can be achieved by using dynamic multiplex scheme, especially when most end-users are watching the same few IPTV programs. Both schemes are implemented in our system, with their hardware and software designs described.

Evaluating accessibility to Bangkok Metro Systems using multi-dimensional criteria across user groups

Directory of Open Access Journals (Sweden)

Duangporn Prasertsubpakij

2012-07-01

Full Text Available Metro systems act as fast and efficient transport systems for many modern metropolises; however, enhancing higher usage of such systems often conflicts with providing suitable accessibility options. The traditional approach of metro accessibility studies seems to be an ineffective measure to gage sustainable access in which the equal rights of all users are taken into account. Bangkok Metropolitan Region (BMR transportation has increasingly relied on the role of two mass rapid transport systems publicly called “BTS Skytrain” and “MRT Subway”, due to limited availability of land and massive road congestion; however, access to such transit arguably treats some vulnerable groups, especially women, the elderly and disabled people unfairly. This study constructs a multi-dimensional assessment of accessibility considerations to scrutinize how user groups access metro services based on BMR empirical case. 600 individual passengers at various stations were asked to rate the questionnaire that simultaneously considers accessibility aspects of spatial, feeder connectivity, temporal, comfort/safety, psychosocial and other dimensions. It was interestingly found by user disaggregated accessibility model that the lower the accessibility perceptions—related uncomfortable and unsafe environment conditions, the greater the equitable access to services, as illustrated by MRT — Hua Lumphong and MRT — Petchaburi stations. The study suggests that, to balance the access priorities of groups on services, policy actions should emphasize acceptably safe access for individuals, cost efficient feeder services connecting the metro lines, socioeconomic influences and time allocation. Insightful discussions on integrated approach balancing different dimensions of accessibility and recommendations would contribute to accessibility-based knowledge and potential propensity to use the public transits towards transport sustainability.

Development of Patient Status-Based Dynamic Access System for Medical Information Systems

Directory of Open Access Journals (Sweden)

Chang Won Jeong

2015-06-01

Full Text Available Recently, the hospital information system environment using IT communication technology and utilization of medical information has been increasing. In the medical field, the medical information system only supports the transfer of patient information to medical staff through an electronic health record, without information about patient status. Hence, it needs a method of real-time monitoring for the patient. Also, in this environment, a secure method in approaching healthcare through various smart devices is required. Therefore, in this paper, in order to classify the status of the patients, we propose a dynamic approach of the medical information system in a hospital information environment using the dynamic access control method. Also, we applied the symmetric method of AES (Advanced Encryption Standard. This was the best encryption algorithm for sending and receiving biological information. We can define usefulness as the dynamic access application service based on the final result of the proposed system. The proposed system is expected to provide a new solution for a convenient medical information system.

Accessing files in an Internet: The Jade file system

Science.gov (United States)

Peterson, Larry L.; Rao, Herman C.

1991-01-01

Jade is a new distribution file system that provides a uniform way to name and access files in an internet environment. It makes two important contributions. First, Jade is a logical system that integrates a heterogeneous collection of existing file systems, where heterogeneous means that the underlying file systems support different file access protocols. Jade is designed under the restriction that the underlying file system may not be modified. Second, rather than providing a global name space, Jade permits each user to define a private name space. These private name spaces support two novel features: they allow multiple file systems to be mounted under one directory, and they allow one logical name space to mount other logical name spaces. A prototype of the Jade File System was implemented on Sun Workstations running Unix. It consists of interfaces to the Unix file system, the Sun Network File System, the Andrew File System, and FTP. This paper motivates Jade's design, highlights several aspects of its implementation, and illustrates applications that can take advantage of its features.

Accessing files in an internet - The Jade file system

Science.gov (United States)

Rao, Herman C.; Peterson, Larry L.

1993-01-01

Jade is a new distribution file system that provides a uniform way to name and access files in an internet environment. It makes two important contributions. First, Jade is a logical system that integrates a heterogeneous collection of existing file systems, where heterogeneous means that the underlying file systems support different file access protocols. Jade is designed under the restriction that the underlying file system may not be modified. Second, rather than providing a global name space, Jade permits each user to define a private name space. These private name spaces support two novel features: they allow multiple file systems to be mounted under one directory, and they allow one logical name space to mount other logical name spaces. A prototype of the Jade File System was implemented on Sun Workstations running Unix. It consists of interfaces to the Unix file system, the Sun Network File System, the Andrew File System, and FTP. This paper motivates Jade's design, highlights several aspects of its implementation, and illustrates applications that can take advantage of its features.

Optimizing man-machine performance of a personnel access restriction security system

International Nuclear Information System (INIS)

Banks, W.W.; Moore, J.W.

1988-01-01

This paper describes a human engineering design and analysis effort for a major security system upgrade at a DOE facility. This upgrade was accomplished by replacing an obsolete and poorly human engineered security screening both the with a new, user oriented, semiautomated, computer-based access control system. Human factors engineers assisted the designer staff in specifying a security access interface to physically and cognitively accommodate all employees which included handicapped individuals in wheel chairs, and several employees who were severely disabled, both visually and aurally. The new access system was intended to control entry into sensitive exclusion areas by requiring personnel to enter a security screening booth and interact with card reader devices and a-simple-to-operate access control panel system. Extensive man-machine testing with prototype mock-ups was conducted to assess human engineered design features and to illuminate potentially confusing or difficult-to-operated hardware placement, layout, and operation sequencing. These evaluations, along with the prototype mock-ups, provided input which resulted in a prototype which was easy to enter, operate, and understand by end users. This prototype later served as the design basis for the final systems design

28 CFR 25.6 - Accessing records in the system.

Science.gov (United States)

2010-07-01

... National Instant Criminal Background Check System § 25.6 Accessing records in the system. (a) FFLs may... through the NCIC communication network. Upon receiving a request for a background check from an FFL, a POC...

Key issues of multiple access technique for LEO satellite communication systems

Institute of Scientific and Technical Information of China (English)

温萍萍; 顾学迈

2004-01-01

The large carrier frequency shift caused by the high-speed movement of satellite (Doppler effects) and the propagation delay on the up-down link are very critical issues in an LEO satellite communication system, which affects both the selection and the implementation of a suitable access method. A Doppler based multiple access technique is used here to control the flow and an MPRMA-HS protocol is proposed for the application in LEO satellite communication systems. The extended simulation trials prove that the proposed scheme seems to be a very promising access method.

CDC STATE System E-Cigarette Legislation - Youth Access

Data.gov (United States)

U.S. Department of Health & Human Services — 1995-2018. Centers for Disease Control and Prevention (CDC). State Tobacco Activities Tracking and Evaluation (STATE) System. E-Cigarette Legislation—Youth Access....

A system for success: BMC Systems Biology, a new open access journal.

Science.gov (United States)

Hodgkinson, Matt J; Webb, Penelope A

2007-09-04

BMC Systems Biology is the first open access journal spanning the growing field of systems biology from molecules up to ecosystems. The journal has launched as more and more institutes are founded that are similarly dedicated to this new approach. BMC Systems Biology builds on the ongoing success of the BMC series, providing a venue for all sound research in the systems-level analysis of biology.

A Protective Mechanism for the Access Control System in the Virtual Domain

Institute of Scientific and Technical Information of China (English)

Jinan Shen; Deqing Zou; Hai Jin; Kai Yang; Bin Yuan; Weiming Li

2016-01-01

In traditional framework,mandatory access control (MAC) system and malicious software are run in kernel mode.Malicious software can stop MAC systems to be started and make it do invalid.This problem cannot be solved under the traditional framework if the operating system (OS) is comprised since malwares are running in ring0 level.In this paper,we propose a novel way to use hypervisors to protect kernel integrity and the access control system in commodity operating systems.We separate the access control system into three parts:policy management (PM),security server (SS) and policy enforcement (PE).Policy management and the security server reside in the security domain to protect them against malware and the isolation feather of the hypervisor can protect them from attacks.We add an access vector cache (AVC) between SS and PE in the guest OS,in order to speed up communication between the guest OS and the security domain.The policy enforcement module is retained in the guest OS for performance.The security of AVC and PE can be ensured by using a memory protection mechanism.The goal of protecting the OS kemel is to ensure the security of the execution path.We implement the system by a modified Xen hypervisor.The result shows that we can secure the security of the access control system in the guest OS with no overhead compared with modules in the latter.Our system offers a centralized security policy for virtual domains in virtual machine environments.

Database application research in real-time data access of accelerator control system

International Nuclear Information System (INIS)

Chen Guanghua; Chen Jianfeng; Wan Tianmin

2012-01-01

The control system of Shanghai Synchrotron Radiation Facility (SSRF) is a large-scale distributed real-time control system, It involves many types and large amounts of real-time data access during the operating. Database system has wide application prospects in the large-scale accelerator control system. It is the future development direction of the accelerator control system, to replace the differently dedicated data structures with the mature standardized database system. This article discusses the application feasibility of database system in accelerators based on the database interface technology, real-time data access testing, and system optimization research and to establish the foundation of the wide scale application of database system in the SSRF accelerator control system. Based on the database interface technology, real-time data access testing and system optimization research, this article will introduce the application feasibility of database system in accelerators, and lay the foundation of database system application in the SSRF accelerator control system. (authors)

Considering User's Access Pattern in Multimedia File Systems

Science.gov (United States)

Cho, KyoungWoon; Ryu, YeonSeung; Won, Youjip; Koh, Kern

2002-12-01

Legacy buffer cache management schemes for multimedia server are grounded at the assumption that the application sequentially accesses the multimedia file. However, user access pattern may not be sequential in some circumstances, for example, in distance learning application, where the user may exploit the VCR-like function(rewind and play) of the system and accesses the particular segments of video repeatedly in the middle of sequential playback. Such a looping reference can cause a significant performance degradation of interval-based caching algorithms. And thus an appropriate buffer cache management scheme is required in order to deliver desirable performance even under the workload that exhibits looping reference behavior. We propose Adaptive Buffer cache Management(ABM) scheme which intelligently adapts to the file access characteristics. For each opened file, ABM applies either the LRU replacement or the interval-based caching depending on the Looping Reference Indicator, which indicates that how strong temporally localized access pattern is. According to our experiment, ABM exhibits better buffer cache miss ratio than interval-based caching or LRU, especially when the workload exhibits not only sequential but also looping reference property.

40 CFR 265.34 - Access to communications or alarm system.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Access to communications or alarm system. 265.34 Section 265.34 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID..., STORAGE, AND DISPOSAL FACILITIES Preparedness and Prevention § 265.34 Access to communications or alarm...

System Hardening Architecture for Safer Access to Critical Business ...

African Journals Online (AJOL)

System Hardening Architecture for Safer Access to Critical Business Data. ... and the threat is growing faster than the potential victims can deal with. ... in this architecture are applied to the host, application, operating system, user, and the ...

CDC STATE System E-Cigarette Legislation - Youth Access

Data.gov (United States)

U.S. Department of Health & Human Services — 1995-2017. Centers for Disease Control and Prevention (CDC). State Tobacco Activities Tracking and Evaluation (STATE) System. E-Cigarette Legislation—Youth Access....

General Controls Over the Electronic Document Access System

National Research Council Canada - National Science Library

2000-01-01

...) system as part of the DoD Paper-Free Contracting Initiative. EDA contributes to the initiative by digitizing paper documents and offering web-based read-only access to official contracting, finance and accounting documents...

Automated biometric access control system for two-man-rule enforcement

International Nuclear Information System (INIS)

Holmes, J.P.; Maxwell, R.L.; Henderson, R.W.

1991-01-01

This paper describes a limited access control system for nuclear facilities which makes use of the eye retinal identity verifier to control the passage of personnel into and out of one or a group of security controlled working areas. This access control system requires no keys, cards or credentials. The user simply enters his Personal Identification Number (PIN) and takes an eye reading to request passage. The PIN does not have to be kept secret. The system then relies on biometric identity verification of the user, along with other system information, to make the decision of whether or not to unlock the door. It also enforces multiple zones control with personnel tracking and the two-man-rule

RFID-Based Monitoring And Access Control System For Parliamentary Campus

Directory of Open Access Journals (Sweden)

Sai Thu Rein Htun

2015-08-01

Full Text Available This paper is to implement monitoring and access control system based on RFID and Zigbee technology which can be used at Parliamentary Campus. Nowadays RFID technology is widely used for access control system because it is cheap waterproof and easy to use as well as it contains unique EPC electronic protect code .In addition Zigbee wireless module is cost-effective and can be reliable for security. Sothis system consists of RFID tag RFID reader Arduino Uno and Zigbee. This system can also be used for industrial amp commercial and security HVAC closures. This paper describes the results of point-to-point connection and point-to-multipoint connection using Zigbee and RFID technology.

Fast Access Data Acquisition System (FADAS)

International Nuclear Information System (INIS)

Katsman, Vladimir

1998-01-01

Our goal in this program is to develop Fast Access Data Acquisition System (FADAS) by combining the flexibility of Multilink's GaAs and InP electronics and electro-optics with an extremely high data rate for the efficient handling and transfer of collider experimental data. This novel solution is based on Multilink's and Los Alamos National Laboratory's (LANL) unique components and technologies for extremely fast data transfer, storage, and processing

Access Safety Systems – New Concepts from the LHC Experience

CERN Document Server

Ladzinski, T; di Luca, S; Hakulinen, T; Hammouti, L; Riesco, T; Nunes, R; Ninin, P; Juget, J-F; Havart, F; Valentini, F; Sanchez-Corral Mena, E

2011-01-01

The LHC Access Safety System has introduced a number of new concepts into the domain of personnel protection at CERN. These can be grouped into several categories: organisational, architectural and concerning the end-user experience. By anchoring the project on the solid foundations of the IEC 61508/61511 methodology, the CERN team and its contractors managed to design, develop, test and commission on time a SIL3 safety system. The system uses a successful combination of the latest Siemens redundant safety programmable logic controllers with a traditional relay logic hardwired loop. The external envelope barriers used in the LHC include personnel and material access devices, which are interlocked door-booths introducing increased automation of individual access control, thus removing the strain from the operators. These devices ensure the inviolability of the controlled zones by users not holding the required credentials. To this end they are equipped with personnel presence detectors and th...

Upper bound for energy efficiency in multi-cell fibre-wireless access systems

NARCIS (Netherlands)

Koonen, A.M.J.; Popov, M.; Wessing, H.

2013-01-01

Bringing radio access points closer to the end-users improves radio energy efficiency. However, taking into account both the radio and the optical parts of a fibre-wireless access system, the overall system energy efficiency has an upper bound determined by the relation between the energy

Upper bound for energy efficiency in multi-cell fibre-wireless access systems

DEFF Research Database (Denmark)

Koonen, A.M.J.; Popov, M.; Wessing, Henrik

2013-01-01

Bringing radio access points closer to the end-users improves radio energy efficiency. However, taking into account both the radio and the optical parts of a fibre-wireless access system, the overall system energy efficiency has an upper bound determined by the relation between the energy...

28 CFR 16.74 - Exemption of National Security Division Systems-limited access.

Science.gov (United States)

2010-07-01

... National Security Division Systems—limited access. (a) The following system of records is exempted from... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Exemption of National Security Division Systems-limited access. 16.74 Section 16.74 Judicial Administration DEPARTMENT OF JUSTICE PRODUCTION OR...

Cardea: Dynamic Access Control in Distributed Systems

Science.gov (United States)

Lepro, Rebekah

2004-01-01

Modern authorization systems span domains of administration, rely on many different authentication sources, and manage complex attributes as part of the authorization process. This . paper presents Cardea, a distributed system that facilitates dynamic access control, as a valuable piece of an inter-operable authorization framework. First, the authorization model employed in Cardea and its functionality goals are examined. Next, critical features of the system architecture and its handling of the authorization process are then examined. Then the S A M L and XACML standards, as incorporated into the system, are analyzed. Finally, the future directions of this project are outlined and connection points with general components of an authorization system are highlighted.

A System to Generate SignWriting for Video Tracks Enhancing Accessibility of Deaf People

Directory of Open Access Journals (Sweden)

Elena Verdú

2017-12-01

Full Text Available Video content has increased much on the Internet during last years. In spite of the efforts of different organizations and governments to increase the accessibility of websites, most multimedia content on the Internet is not accessible. This paper describes a system that contributes to make multimedia content more accessible on the Web, by automatically translating subtitles in oral language to SignWriting, a way of writing Sign Language. This system extends the functionality of a general web platform that can provide accessible web content for different needs. This platform has a core component that automatically converts any web page to a web page compliant with level AA of WAI guidelines. Around this core component, different adapters complete the conversion according to the needs of specific users. One adapter is the Deaf People Accessibility Adapter, which provides accessible web content for the Deaf, based on SignWritting. Functionality of this adapter has been extended with the video subtitle translator system. A first prototype of this system has been tested through different methods including usability and accessibility tests and results show that this tool can enhance the accessibility of video content available on the Web for Deaf people.

Prospective evaluation of an internet-linked handheld computer critical care knowledge access system.

Science.gov (United States)

Lapinsky, Stephen E; Wax, Randy; Showalter, Randy; Martinez-Motta, J Carlos; Hallett, David; Mehta, Sangeeta; Burry, Lisa; Stewart, Thomas E

2004-12-01

Critical care physicians may benefit from immediate access to medical reference material. We evaluated the feasibility and potential benefits of a handheld computer based knowledge access system linking a central academic intensive care unit (ICU) to multiple community-based ICUs. Four community hospital ICUs with 17 physicians participated in this prospective interventional study. Following training in the use of an internet-linked, updateable handheld computer knowledge access system, the physicians used the handheld devices in their clinical environment for a 12-month intervention period. Feasibility of the system was evaluated by tracking use of the handheld computer and by conducting surveys and focus group discussions. Before and after the intervention period, participants underwent simulated patient care scenarios designed to evaluate the information sources they accessed, as well as the speed and quality of their decision making. Participants generated admission orders during each scenario, which were scored by blinded evaluators. Ten physicians (59%) used the system regularly, predominantly for nonmedical applications (median 32.8/month, interquartile range [IQR] 28.3-126.8), with medical software accessed less often (median 9/month, IQR 3.7-13.7). Eight out of 13 physicians (62%) who completed the final scenarios chose to use the handheld computer for information access. The median time to access information on the handheld handheld computer was 19 s (IQR 15-40 s). This group exhibited a significant improvement in admission order score as compared with those who used other resources (P = 0.018). Benefits and barriers to use of this technology were identified. An updateable handheld computer system is feasible as a means of point-of-care access to medical reference material and may improve clinical decision making. However, during the study, acceptance of the system was variable. Improved training and new technology may overcome some of the barriers we

Return Migrants’ Experience of Access to Care in Corrupt Healthcare Systems

DEFF Research Database (Denmark)

Handlos, Line Neerup; Olwig, Karen Fog; Bygbjerg, Ib Christian

2016-01-01

unstudied, even though return migrants may be particularly vulnerable to problems related to corruption due to their period of absence from their country of origin. This article investigates how corruption in the healthcare sector affects access to healthcare for refugees who repatriated to Bosnia......Equal and universal access to healthcare services is a core priority for a just health system. A key societal determinant seen to create inequality in access to healthcare is corruption in the healthcare system. How return migrants’ access to healthcare is affected by corruption is largely......, a country with a high level of corruption, from Denmark, a country with a low level of corruption. The study is based on 18 semi-structured interviews with 33 refugees who returned after long-term residence in Denmark. We found that the returned refugees faced greater problems with corruption than...

An Information System to Access Status Information of the LHCb Online

International Nuclear Information System (INIS)

Frank, M; Gaspar, C

2012-01-01

The LHCb collaboration consists of roughly 700 physicists from 52 institutes and universities. Most of the collaborating physicists - including subdetector experts - are not permanently based at CERN. This paper describes the architecture used to publish data internal to the LHCb experiment control- and data acquisition system to the World Wide Web. Collaborators can access the online (sub-) system status and the system performance directly from the institute abroad, from home or from a smart phone without the need of direct access to the online computing infrastructure.

On the Protection of Personal Data in the Access Control System

Directory of Open Access Journals (Sweden)

A. P. Durakovskiy

2012-03-01

Full Text Available The aim is to prove the qualification system of access control systems (ACS as an information system for personal data (ISPDn. Applications: systems of physical protection of facilities.

A System for Web-based Access to the HSOS Database

Science.gov (United States)

Lin, G.

Huairou Solar Observing Station's (HSOS) magnetogram and dopplergram are world-class instruments. Access to their data has opened to the world. Web-based access to the data will provide a powerful, convenient tool for data searching and solar physics. It is necessary that our data be provided to users via the Web when it is opened to the world. In this presentation, the author describes general design and programming construction of the system. The system will be generated by PHP and MySQL. The author also introduces basic feature of PHP and MySQL.

An Efficient Role and Object Based Access Control Model Implemented in a PDM System

Institute of Scientific and Technical Information of China (English)

HUANG Xiaowen; TAN Jian; HUANG Xiangguo

2006-01-01

An effective and reliable access control is crucial to a PDM system. This article has discussed the commonly used access control models, analyzed their advantages and disadvantages, and proposed a new Role and Object based access control model that suits the particular needs of a PDM system. The new model has been implemented in a commercial PDM system, which has demonstrated enhanced flexibility and convenience.

Cognitive radio networks medium access control for coexistence of wireless systems

CERN Document Server

Bian, Kaigui; Gao, Bo

2014-01-01

This book gives a comprehensive overview of the medium access control (MAC) principles in cognitive radio networks, with a specific focus on how such MAC principles enable different wireless systems to coexist in the same spectrum band and carry out spectrum sharing.  From algorithm design to the latest developments in the standards and spectrum policy, readers will benefit from leading-edge knowledge of how cognitive radio systems coexist and share spectrum resources.  Coverage includes cognitive radio rendezvous, spectrum sharing, channel allocation, coexistence in TV white space, and coexistence of heterogeneous wireless systems.   • Provides a comprehensive reference on medium access control (MAC)-related problems in the design of cognitive radio systems and networks; • Includes detailed analysis of various coexistence problems related to medium access control in cognitive radio networks; • Reveals novel techniques for addressing the challenges of coexistence protocol design at a higher level ...

Optimized scheduling technique of null subcarriers for peak power control in 3GPP LTE downlink.

Science.gov (United States)

Cho, Soobum; Park, Sang Kyu

2014-01-01

Orthogonal frequency division multiple access (OFDMA) is a key multiple access technique for the long term evolution (LTE) downlink. However, high peak-to-average power ratio (PAPR) can cause the degradation of power efficiency. The well-known PAPR reduction technique, dummy sequence insertion (DSI), can be a realistic solution because of its structural simplicity. However, the large usage of subcarriers for the dummy sequences may decrease the transmitted data rate in the DSI scheme. In this paper, a novel DSI scheme is applied to the LTE system. Firstly, we obtain the null subcarriers in single-input single-output (SISO) and multiple-input multiple-output (MIMO) systems, respectively; then, optimized dummy sequences are inserted into the obtained null subcarrier. Simulation results show that Walsh-Hadamard transform (WHT) sequence is the best for the dummy sequence and the ratio of 16 to 20 for the WHT and randomly generated sequences has the maximum PAPR reduction performance. The number of near optimal iteration is derived to prevent exhausted iterations. It is also shown that there is no bit error rate (BER) degradation with the proposed technique in LTE downlink system.

Access to justice in the Convention on Rights system

NARCIS (Netherlands)

Gerards, J.H.; Glas, L.R.

2017-01-01

The numerous reforms to the Convention system of the past two decades have unquestionably had an effect on applicants’ means to access justice in the system. It is, however, open to question how these changes should be evaluated: with reference to the individual right to petition, or with reference

Experimental demonstration of IDMA-OFDM for passive optical network

Science.gov (United States)

Lin, Bangjiang; Tang, Xuan; Li, Yiwei; Zhang, Min; Lin, Chun; Ghassemlooy, Zabih

2017-11-01

We present interleave division multiple access (IDMA) scheme combined with orthogonal frequency division multiplexing (OFDM) for passive optical network, which offers improved transmission performance and good chromatic dispersion tolerance. The interleavers are employed to separate different users and the generated chips are modulated on OFDM subcarriers. The feasibility of IDMA-OFDM-PON is experimentally verified with a bitrate of 3.3 Gb/s per user. Compared with OFDMA, IDMA-OFDM offers 8 and 6 dB gains in term of receiver sensitivity in the cases of 2 and 4 users, respectively.

Assessment of Deafblind Access to Manual Language Systems (ADAMLS)

Science.gov (United States)

Blaha, Robbie; Carlson, Brad

2007-01-01

This document presents the Assessment of Deafblind Access to Manual Language Systems (ADAMLS), a resource for educational teams who are responsible for developing appropriate adaptations and strategies for children who are deafblind who are candidates for learning manual language systems. The assessment tool should be used for all children with a…

Access to essential medicines in Pakistan: policy and health systems research concerns.

Directory of Open Access Journals (Sweden)

Shehla Zaidi

Full Text Available INTRODUCTION: Inadequate access to essential medicines is a common issue within developing countries. Policy response is constrained, amongst other factors, by a dearth of in-depth country level evidence. We share here i gaps related to access to essential medicine in Pakistan; and ii prioritization of emerging policy and research concerns. METHODS: An exploratory research was carried out using a health systems perspective and applying the WHO Framework for Equitable Access to Essential Medicine. Methods involved key informant interviews with policy makers, providers, industry, NGOs, experts and development partners, review of published and grey literature, and consultative prioritization in stakeholder's Roundtable. FINDINGS: A synthesis of evidence found major gaps in essential medicine access in Pakistan driven by weaknesses in the health care system as well as weak pharmaceutical regulation. 7 major policy concerns and 11 emerging research concerns were identified through consultative Roundtable. These related to weaknesses in medicine registration and quality assurance systems, unclear and counterproductive pricing policies, irrational prescribing and sub-optimal drug availability. Available research, both locally and globally, fails to target most of the identified policy concerns, tending to concentrate on irrational prescriptions. It overlooks trans-disciplinary areas of policy effectiveness surveillance, consumer behavior, operational pilots and pricing interventions review. CONCLUSION: Experience from Pakistan shows that policy concerns related to essential medicine access need integrated responses across various components of the health systems, are poorly addressed by existing evidence, and require an expanded health systems research agenda.

Providers' Access of Imaging Versus Only Reports: A System Log File Analysis.

Science.gov (United States)

Jung, Hye-Young; Gichoya, Judy Wawira; Vest, Joshua R

2017-02-01

An increasing number of technologies allow providers to access the results of imaging studies. This study examined differences in access of radiology images compared with text-only reports through a health information exchange system by health care professionals. The study sample included 157,256 historical sessions from a health information exchange system that enabled 1,670 physicians and non-physicians to access text-based reports and imaging over the period 2013 to 2014. The primary outcome was an indicator of access of an imaging study instead of access of a text-only report. Multilevel mixed-effects regression models were used to estimate the association between provider and session characteristics and access of images compared with text-only reports. Compared with primary care physicians, specialists had an 18% higher probability of accessing actual images instead of text-only reports (β = 0.18; P < .001). Compared with primary care practice settings, the probability of accessing images was 4% higher for specialty care practices (P < .05) and 8% lower for emergency departments (P < .05). Radiologists, orthopedists, and neurologists accounted for 79% of all the sessions with actual images accessed. Orthopedists, radiologists, surgeons, and pulmonary disease specialists accessed imaging more often than text-based reports only. Consideration for differences in the need to access images compared with text-only reports based on the type of provider and setting of care are needed to maximize the benefits of image sharing for patient care. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Development of a wireless protection against imitation system for identification and control of vehicle access

Directory of Open Access Journals (Sweden)

Aleksei A. Gavrishev

2018-03-01

Full Text Available This article deals with wireless systems for identification and control of vehicle access to protected objects. Known systems are considered. As a result, it has been established that one of the most promising approaches to identifying and controlling vehicle access to protected objects is the use of systems based on the "friend or foe" principle. Among these systems, there are "one-directional" and "bedirectional" identification and access control systems. "Bidirectional" systems are more preferable for questions of identification and access control. However, at present, these systems should have a reduced probability of recognizing the structure of the request and response signals because the potential attacker can easily perform unauthorized access to the radio channel of the system. On this basis, developed a wireless system identification and control vehicle access to protected objects based on the principle of "friend or foe", featuring increased protection from unauthorized access and jamming through the use of rewritable drives chaotic sequences. In addition, it’s proposed to use to identify the vehicle's RFID tag containing additional information about it. Are some specifications of the developed system (the possible frequency range of the request-response signals, the communication range, data rate, the size of the transmitted data, guidelines for choosing RFID. Also, with the help of fuzzy logic, was made the security assessment from unauthorized access request-response signals based on the system of "friend or foe", which are transferred via radio channel, developed systems and analogues. The security assessment of the developed system shows an adequate degree of protection against complex threats (view, spoofing, interception and jamming of traffic in comparison with known systems of this class. Among the main advantages of the developed system it’s necessary to mention increased security from unauthorized access and jamming

Problems and Concerns Regarding Access Control System Construction in Radiation Facilities Based on the NIFS Experience

International Nuclear Information System (INIS)

Kawano, T.; Inoue, N.; Sakuma, Y.; Motojima, O.

2001-01-01

Full text: In 1998, access control system for the large helical device (LHD) experimental hall was constructed and put into operation at the National Institute for Fusion Science (NIFS) in Toki, Japan. Since then, the system has been continuously improved. It now controls access into the LHD controlled area through four entrances. The system has five turnstile gates and enables control of access at the four entrances. The system is always checking whether the shielding doors are open or closed at eight positions. The details pertaining to the construction of the system were reported at IRPA-10 held in Hiroshima, Japan, in 2000. Based on our construction experience of the NIFS access control system, we will discuss problems related to software and operational design of the system. We will also discuss some concerns regarding the use of the system in radiation facilities. The problems we will present concern, among other thing, individual registration, time control, turnstile control, interlock signal control, data aggregation and transactions, automatic and manual control, and emergency procedures. For example, in relation to the time control and turnstile control functions, we will discuss the gate-opening time interval for an access event, the timing of access data recording, date changing, turn bar control, double access, and access error handling. (author)

Data Access System for Hydrology

Science.gov (United States)

Whitenack, T.; Zaslavsky, I.; Valentine, D.; Djokic, D.

2007-12-01

As part of the CUAHSI HIS (Consortium of Universities for the Advancement of Hydrologic Science, Inc., Hydrologic Information System), the CUAHSI HIS team has developed Data Access System for Hydrology or DASH. DASH is based on commercial off the shelf technology, which has been developed in conjunction with a commercial partner, ESRI. DASH is a web-based user interface, developed in ASP.NET developed using ESRI ArcGIS Server 9.2 that represents a mapping, querying and data retrieval interface over observation and GIS databases, and web services. This is the front end application for the CUAHSI Hydrologic Information System Server. The HIS Server is a software stack that organizes observation databases, geographic data layers, data importing and management tools, and online user interfaces such as the DASH application, into a flexible multi- tier application for serving both national-level and locally-maintained observation data. The user interface of the DASH web application allows online users to query observation networks by location and attributes, selecting stations in a user-specified area where a particular variable was measured during a given time interval. Once one or more stations and variables are selected, the user can retrieve and download the observation data for further off-line analysis. The DASH application is highly configurable. The mapping interface can be configured to display map services from multiple sources in multiple formats, including ArcGIS Server, ArcIMS, and WMS. The observation network data is configured in an XML file where you specify the network's web service location and its corresponding map layer. Upon initial deployment, two national level observation networks (USGS NWIS daily values and USGS NWIS Instantaneous values) are already pre-configured. There is also an optional login page which can be used to restrict access as well as providing a alternative to immediate downloads. For large request, users would be notified via

NASA Access Mechanism - Graphical user interface information retrieval system

Science.gov (United States)

Hunter, Judy F.; Generous, Curtis; Duncan, Denise

1993-01-01

Access to online information sources of aerospace, scientific, and engineering data, a mission focus for NASA's Scientific and Technical Information Program, has always been limited by factors such as telecommunications, query language syntax, lack of standardization in the information, and the lack of adequate tools to assist in searching. Today, the NASA STI Program's NASA Access Mechanism (NAM) prototype offers a solution to these problems by providing the user with a set of tools that provide a graphical interface to remote, heterogeneous, and distributed information in a manner adaptable to both casual and expert users. Additionally, the NAM provides access to many Internet-based services such as Electronic Mail, the Wide Area Information Servers system, Peer Locating tools, and electronic bulletin boards.

NASA access mechanism: Graphical user interface information retrieval system

Science.gov (United States)

Hunter, Judy; Generous, Curtis; Duncan, Denise

1993-01-01

Access to online information sources of aerospace, scientific, and engineering data, a mission focus for NASA's Scientific and Technical Information Program, has always been limited to factors such as telecommunications, query language syntax, lack of standardization in the information, and the lack of adequate tools to assist in searching. Today, the NASA STI Program's NASA Access Mechanism (NAM) prototype offers a solution to these problems by providing the user with a set of tools that provide a graphical interface to remote, heterogeneous, and distributed information in a manner adaptable to both casual and expert users. Additionally, the NAM provides access to many Internet-based services such as Electronic Mail, the Wide Area Information Servers system, Peer Locating tools, and electronic bulletin boards.

Systemic barriers accessing HIV treatment among people who inject drugs in Russia: a qualitative study.

Science.gov (United States)

Sarang, Anya; Rhodes, Tim; Sheon, Nicolas

2013-10-01

Achieving 'universal access' to antiretroviral HIV treatment (ART) in lower income and transitional settings is a global target. Yet, access to ART is shaped by local social condition and is by no means universal. Qualitative studies are ideally suited to describing how access to ART is socially situated. We explored systemic barriers to accessing ART among people who inject drugs (PWID) in a Russian city (Ekaterinburg) with a large burden of HIV treatment demand. We undertook 42 in-depth qualitative interviews with people living with HIV with current or recent experience of injecting drug use. Accounts were analysed thematically, and supplemented here with an illustrative case study. Three core themes were identified: 'labyrinthine bureaucracy' governing access to ART; a 'system Catch 22' created by an expectation that access to ART was conditional upon treated drug use in a setting of limited drug treatment opportunity; and 'system verticalization', where a lack of integration across HIV, tuberculosis (TB) and drug treatment compromised access to ART. Taken together, we find that systemic factors play a key role in shaping access to ART with the potential adverse effects of reproducing treatment initiation delay and disengagement from treatment. We argue that meso-level systemic factors affecting access to ART for PWID interact with wider macro-level structural forces, including those related to drug treatment policy and the social marginalization of PWID. We note the urgent need for systemic and structural changes to improve access to ART for PWID in this setting, including to simplify bureaucratic procedures, foster integrated HIV, TB and drug treatment services, and advocate for drug treatment policy reform.

Fair Adaptive Bandwidth and Subchannel Allocation in the WiMAX Uplink

Directory of Open Access Journals (Sweden)

Antoni Morell

2009-01-01

Full Text Available In some modern communication systems, as it is the case of WiMAX, it has been decided to implement Demand Assignment Multiple Access (DAMA solutions. End-users request transmission opportunities before accessing the system, which provides an efficient way to share system resources. In this paper, we briefly review the PHY and MAC layers of an OFDMA-based WiMAX system, and we propose to use a Network Utility Maximization (NUM framework to formulate the DAMA strategy foreseen in the uplink of IEEE 802.16. Utility functions are chosen to achieve fair solutions attaining different degrees of fairness and to further support the QoS requirements of the services in the system. Moreover, since the standard allocates resources in a terminal basis but each terminal may support several services, we develop a new decomposition technique, the coupled-decompositions method, that obtains the optimal service flow allocation with a small number of iterations (the improvement is significant when compared to other known solutions. Furthermore, since the PHY layer in mobile WiMAX has the means to adapt the transport capacities of the links between the Base Station (BS and the Subscriber Stations (SSs, the proposed PHY-MAC cross-layer design uses this extra degree of freedom in order to enhance the network utility.

Interactive water monitoring system accessible by cordless telephone

Science.gov (United States)

Volpicelli, Richard; Andeweg, Pierre; Hagar, William G.

1985-12-01

A battery-operated, microcomputer-controlled monitoring device linked with a cordless telephone has been developed for remote measurements. This environmental sensor is self-contained and collects and processes data according to the information sent to its on-board computer system. An RCA model 1805 microprocessor forms the basic controller with a program encoded in memory for data acquisition and analysis. Signals from analog sensing devices used to monitor the environment are converted into digital signals and stored in random access memory of the microcomputer. This remote sensing system is linked to the laboratory by means of a cordless telephone whose base unit is connected to regular telephone lines. This offshore sensing system is simply accessed by a phone call originating from a computer terminal in the laboratory. Data acquisition is initiated upon request: Information continues to be processed and stored until the computer is reprogrammed by another phone call request. Information obtained may be recalled by a phone call after the desired environmental measurements are finished or while they are in progress. Data sampling parameters may be reset at any time, including in the middle of a measurement cycle. The range of the system is limited only by existing telephone grid systems and by the transmission characteristics of the cordless phone used as a communications link. This use of a cordless telephone, coupled with the on-board computer system, may be applied to other field studies requiring data transfer between an on-site analytical system and the laboratory.

Performance Analysis of DPSK-OCDMA System for Optical Access Network

Science.gov (United States)

Islam, Monirul; Ahmed, N.; Aljunid, S. A.; Ali, Sharafat; Sayeed, S.; Sabri, Naseer

2016-03-01

In this research, the performance of optical code division multiple access (OCDMA) using differential phase shift keying (DPSK) has been compared with OCDMA On-Off Keying (OOK). This comparison took place in terms of bit error rate (BER) and receiver power where two bit rates (155 Mbps and 622 Mbps) have been used for this analysis. Using of OptiSystem 7.0 simulation, comparing eye diagram and optical spectrum alongside with BER and Rx power. It is found that OCDMA-DPSK performs better in comparison to OCDMA-OOK. The performance analysis also provides parameter for designing and development of an OCDMA system for optical access network using DPSK.

A system for success: BMC Systems Biology, a new open access journal

OpenAIRE

Webb Penelope A; Hodgkinson Matt J

2007-01-01

Abstract BMC Systems Biology is the first open access journal spanning the growing field of systems biology from molecules up to ecosystems. The journal has launched as more and more institutes are founded that are similarly dedicated to this new approach. BMC Systems Biology builds on the ongoing success of the BMC series, providing a venue for all sound research in the systems-level analysis of biology.

Email based remote access and surveillance system for smart home infrastructure

Directory of Open Access Journals (Sweden)

Pooshkar Rajiv

2016-09-01

Full Text Available With the rapid rise of Internet of Things in public domain, people expect fast, reliable and on-demand home security via the Internet. However, existing remote home surveillance systems place a very rigid constraint on authentication and require customized hardware and software. In this paper we have proposed an ingenious and reliable internet based, home access system for smart homes that can be easily deployed on generic hardware. The proposed architecture uses popular email service providers to notify and update the user about the home access. It sends an email to the owner with the attached picture of the person who is at the door. It also incorporates a protected mechanism to give access of the door to a remote user by responding to that email. It essentially means that we can view and give access to the person at our door via sending and receiving an email. Furthermore, an image processing based mechanism has also been incorporated to provide access without email, to few selected personnel who are trusted by the owner. It works by capturing and comparing the visitor's image with the stored images in the database. Perceptual hashing or fingerprint matching algorithm is used for comparison purposes. Similarity percentage based on hamming distance was evaluated, and the similarity threshold for providing access was set. The simulations were performed in rigorous environment. The efficiency of the hashing algorithm was found to be 97% at the similarity threshold of 95%. The results validate that the average latency is only 155 ms with low standard deviation. The CPU utilization remained quite low with a minimum value of 10 MHz and a maximum value of 30 MHz when the payload size of the sent mail was increased to 1500 kB. Thus, the proposed system can be used for developing a larger low power infrastructure.

Discrete rate resource allocation for OFDMA cognitive radio systems with location information

KAUST Repository

Ben Ghorbel, Mahdi; Nam, Haewoon; Alouini, Mohamed-Slim

2010-01-01

In this paper we introduce a resource allocation algorithm based on location information for cognitive radio systems. The location information allows a practical implementation of cognitive radio systems when the channel state knowledge of the interference links with the primary users is not available. Using this information and measurements, the secondary users estimate the pathloss between the secondary and primary users to avoid interfering the primary users while sharing the frequency bands. The major improvement in this paper is low-complex algorithms for downlink and uplink resource allocations with integer bit distributions, where collocated subchannel constraint is considered in uplink case. We show, through numerical simulations, that for the downlink case, the proposed algorithm is indeed optimal while for the uplink case, it is near-optimal. ©2010 IEEE.

Discrete rate resource allocation for OFDMA cognitive radio systems with location information

KAUST Repository

Ben Ghorbel, Mahdi

2010-09-01

In this paper we introduce a resource allocation algorithm based on location information for cognitive radio systems. The location information allows a practical implementation of cognitive radio systems when the channel state knowledge of the interference links with the primary users is not available. Using this information and measurements, the secondary users estimate the pathloss between the secondary and primary users to avoid interfering the primary users while sharing the frequency bands. The major improvement in this paper is low-complex algorithms for downlink and uplink resource allocations with integer bit distributions, where collocated subchannel constraint is considered in uplink case. We show, through numerical simulations, that for the downlink case, the proposed algorithm is indeed optimal while for the uplink case, it is near-optimal. ©2010 IEEE.

The upgrade of the J-TEXT experimental data access and management system

International Nuclear Information System (INIS)

Yang, C.; Zhang, M.; Zheng, W.; Liu, R.; Zhuang, G.

2014-01-01

Highlights: • The J-TEXT DAMS is developed based on B/S model, which makes it conveniently access the system. • The JWeb-Scope adopts segment strategy to read data that improve the speed of reading data. • DAMS have integrated the management and JWeb-Scope and make an easy way for visitors to access the experiment data. • The JWeb-Scope can be visited all over the world, plot experiment data and zoom in or out smoothly. - Abstract: The experimental data of J-TEXT tokamak are stored in the MDSplus database. The old J-TEXT data access system is based on the tools provided by MDSplus. Since the number of signals is huge, the data retrieval for an experiment is difficult. To solve this problem, the J-TEXT experimental data access and management system (DAMS) based on MDSplus has been developed. The DAMS left the old MDSplus system unchanged providing new tools, which can help users to handle all signals as well as to retrieve signals they need thanks to the user information requirements. The DAMS also offers users a way to create their jScope configuration files which can be downloaded to the local computer. In addition, the DAMS provides a JWeb-Scope tool to visualize the signal in a browser. JWeb-Scope adopts segment strategy to read massive data efficiently. Users can plot one or more signals on their own choice and zoom-in, zoom-out smoothly. The whole system is based on B/S model, so that the users only need of the browsers to access the DAMS. The DAMS has been tested and it has a better user experience. It will be integrated into the J-TEXT remote participation system later

Providing Access to Library Automation Systems for Students with Disabilities.

Science.gov (United States)

California Community Colleges, Sacramento. High-Tech Center for the Disabled.

This document provides information on the integration of assistive computer technologies and library automation systems at California Community Colleges in order to ensure access for students with disabilities. Topics covered include planning, upgrading, purchasing, implementing and using these technologies with library systems. As information…

What systems participants know about access and service entry and why managers should listen.

Science.gov (United States)

Duncombe, Rohena

2017-08-01

Objective The present study looked at the views of people directly involved in the entry process for community health counselling using the frame of the health access literature. The concurrence of system participants' views with the access literature highlights access issues, particularly for people who are vulnerable or disadvantaged. The paper privileges the voices of the system participants, inviting local health services to consider using participatory design to improve access at the entry point. Methods People involved in the entry process for community health counselling explored the question, 'What, for you, are the features of a good intake system?' They also commented on themes identified during pilot interviews. These were thematically analysed for each participant group by the researcher to develop a voice for each stakeholder group. Results People accessing the service could be vulnerable and the entry process failed to take that into account. People directly involved in the counselling service entry system, system participants, consisted of: professionals referring in, people seeking services and reception staff taking first enquiries. They shared substantially the same concerns as each other. The responses from these system participants are consistent with the international literature on access and entry into health services. Conclusion Participatory service design could improve primary healthcare service entry at the local level. Canvassing the experiences of system participants is important for delivering services to those who have the least access and, in that way, could contribute to health equity. What is known about the topic? People with the highest health needs receive the fewest services. Health inequality is increasing. What does this paper add? System participants can provide advice consistent with the academic research literature that is useful for improving service entry at the local level. What are the implications for practitioners

Average opportunity-based accessibility of public transit systems to grocery stores in small urban areas

Directory of Open Access Journals (Sweden)

Nimish Dharmadhikari

2015-12-01

Full Text Available This research studies the accessibility of grocery stores to university students using the public transportation system, drawing from a case study of Fargo, North Dakota. Taking into consideration the combined travel time components of walking, riding, and waiting, this study measures two types of accessibilities: accessibility to reach a particular place and accessibility to reach the bus stop to ride the public transit system. These two accessibilities are interdependent and cannot perform without each other. A new method to calculate the average accessibility measure for the transit routes is proposed. A step-wise case study analysis indicates that one route provides accessibility to a grocery store in eight minutes. This also suggests that the North Dakota State University area has moderate accessibility to grocery stores.

Design and Implementation of a Library and Information Science Open Access Journal Union Catalogue System

Directory of Open Access Journals (Sweden)

Sinn-Cheng Lin

2017-03-01

Full Text Available Open access is a mode of academic communication that has been on the rise in recent years, but open access academic resources are widely dispersed across the internet, making it occasionally inconvenient in terms of its use. This research is focused on library and information science, using the OAIS reference model as the system framework, two open access platform, DOAJ and E-LIS as the data sources, and through system implementation develop a “library and information science open access journal union catalogue” system. Using the OAI-PMH protocol as the data interoperability standard, and LAMP as the development environment, four major functionalities: injest, archiving, management and access of information were designed, developed, and integrated into system build. Actual testing and verification showed this system is able to successfully collect data from DOAJ and E-LIS open journal resources related to library and information science. The system is now active and functional, and can be used by researchers in the library and science information field.

A semi-automated vascular access system for preclinical models

International Nuclear Information System (INIS)

Berry-Pusey, B N; David, J; Taschereau, R; Silverman, R W; Williams, D; Ladno, W; Stout, D; Chatziioannou, A; Chang, Y C; Prince, S W; Chu, K; Tsao, T C

2013-01-01

Murine models are used extensively in biological and translational research. For many of these studies it is necessary to access the vasculature for the injection of biologically active agents. Among the possible methods for accessing the mouse vasculature, tail vein injections are a routine but critical step for many experimental protocols. To perform successful tail vein injections, a high skill set and experience is required, leaving most scientists ill-suited to perform this task. This can lead to a high variability between injections, which can impact experimental results. To allow more scientists to perform tail vein injections and to decrease the variability between injections, a vascular access system (VAS) that semi-automatically inserts a needle into the tail vein of a mouse was developed. The VAS uses near infrared light, image processing techniques, computer controlled motors, and a pressure feedback system to insert the needle and to validate its proper placement within the vein. The VAS was tested by injecting a commonly used radiolabeled probe (FDG) into the tail veins of five mice. These mice were then imaged using micro-positron emission tomography to measure the percentage of the injected probe remaining in the tail. These studies showed that, on average, the VAS leaves 3.4% of the injected probe in the tail. With these preliminary results, the VAS system demonstrates the potential for improving the accuracy of tail vein injections in mice. (paper)

The optimal access system for future far-offshore wind farms

Energy Technology Data Exchange (ETDEWEB)

Obdam, T.S.; Rademakers, L.W.M.M.; Savenije, L.B. [ECN Wind Energy, Petten (Netherlands)

2013-12-15

Operation and maintenance (O and M) of offshore wind turbines is one of the main cost drivers of offshore wind energy. One of the aspects critical for an efficient and cost-effective O and M strategy is the selection of the access system which is used to transfer technicians and, optionally, small spare parts. Currently, most offshore wind farms are located close to shore, and their size is relatively small. For these farms the typical access system consists of catamaran-like workboats, which are used to transfer both technicians and small spare parts. As wind farms move further offshore this O and M concept might no longer be cost-effective. Currently, different alternative O and M concepts are being considered for the future far-offshore sites. In this paper an extensive and holistic comparison of different O and M concepts including different access system solutions is presented. This analysis has been performed using the OMCECalculator, ECN's software for advanced O and M cost modelling. Different sites have been considered, which are typical for the future offshore wind farms that will be commissioned during the next five years. The results of the performed analyses indicate that when moving further offshore harbour-based O and M strategies are no longer economical, even when helicopters are added to the mix. Looking at farm-based O and M concepts a supply vessel with a compensated access gangway offers great potential. However, the calculations also indicate that its ability to transfer small spare parts, in addition to technicians, is crucial.

Asynchronous Free-Space Optical CDMA Communications System for Last-mile Access Network

DEFF Research Database (Denmark)

Jurado-Navas, Antonio; Raddo, Thiago R.; Sanches, Anderson L.

2016-01-01

We propose a new hybrid asynchronous OCDMA-FSO communications system for access network solutions. New ABER expressions are derived under gamma-gamma scintillation channels, where all users can surprisingly achieve error-free transmissions when FEC is employed.......We propose a new hybrid asynchronous OCDMA-FSO communications system for access network solutions. New ABER expressions are derived under gamma-gamma scintillation channels, where all users can surprisingly achieve error-free transmissions when FEC is employed....

Distributed magnetic field positioning system using code division multiple access

Science.gov (United States)

Prigge, Eric A. (Inventor)

2003-01-01

An apparatus and methods for a magnetic field positioning system use a fundamentally different, and advantageous, signal structure and multiple access method, known as Code Division Multiple Access (CDMA). This signal architecture, when combined with processing methods, leads to advantages over the existing technologies, especially when applied to a system with a large number of magnetic field generators (beacons). Beacons at known positions generate coded magnetic fields, and a magnetic sensor measures a sum field and decomposes it into component fields to determine the sensor position and orientation. The apparatus and methods can have a large `building-sized` coverage area. The system allows for numerous beacons to be distributed throughout an area at a number of different locations. A method to estimate position and attitude, with no prior knowledge, uses dipole fields produced by these beacons in different locations.

The design and implementation of access control management system in IHEP network

International Nuclear Information System (INIS)

Wang Yanming; An Dehai; Qi Fazhi

2010-01-01

In campus network environment of Institute of High Energy Physics, because of the number of Network devices and computers are large scale, ensuring the access validity of network devices and user's computer, and aiming at effective control the exceptional network communication are technological means to achieve network normal running. The access control system of Campus network of institute of High Energy Physics using MySQL database in the behind, and using CGI PHP HTML language to develop the front interface. The System achieves user information management, user computer access control, cutting down the exceptional network communication and alarm function. Increasing the management effective of network, to ensure campus network safety and reliable running. (authors)

Towards Payment Systems for all: accessible POS

Directory of Open Access Journals (Sweden)

Begoña Pino

2014-10-01

Full Text Available The project presented here is a first step towards building a more accessible world through Payment Systems and a successful implementation of a User Centred Design. By means of a beep-system, a Point of Sale (POS payment device informs the user of those transaction steps that require his/her attention at the moment of payment, such as when: the card has been successfully read, the Personal Identification Number (PIN must be entered, the transaction has been successfully processed and the transaction has not been completed due to an error. The proposed solution increases the personal autonomy and security of blind people when paying at a merchant.

From System Expansion to System Contraction: Access to Higher Education in Poland

Science.gov (United States)

Kwiek, Marek

2013-01-01

Access to higher education in Poland is changing due to the demography of smaller cohorts of potential students. Following a demand-driven educational expansion after the collapse of communism in 1989, the higher education system is now contracting. Such expansion/contraction and growth/decline in European higher education has rarely been…

DOE's nation-wide system for access control can solve problems for the federal government

International Nuclear Information System (INIS)

Callahan, S.; Tomes, D.; Davis, G.; Johnson, D.; Strait, S.

1996-07-01

The U.S. Department of Energy's (DOE's) ongoing efforts to improve its physical and personnel security systems while reducing its costs, provide a model for federal government visitor processing. Through the careful use of standardized badges, computer databases, and networks of automated access control systems, the DOE is increasing the security associated with travel throughout the DOE complex, and at the same time, eliminating paperwork, special badging, and visitor delays. The DOE is also improving badge accountability, personnel identification assurance, and access authorization timeliness and accuracy. Like the federal government, the DOE has dozens of geographically dispersed locations run by many different contractors operating a wide range of security systems. The DOE has overcome these obstacles by providing data format standards, a complex-wide virtual network for security, the adoption of a standard high security system, and an open-systems-compatible link for any automated access control system. If the location's level of security requires it, positive visitor identification is accomplished by personal identification number (PIN) and/or by biometrics. At sites with automated access control systems, this positive identification is integrated into the portals

A mobile console for local access to accelerator control systems.

CERN Multimedia

1981-01-01

Microprocessors were installed as auxiliary crate controllers (ACCs) in the CAMAC interface of control systems for various accelerators. The same ACC was also at the hearth of a stand-alone system in the form of a mobile console. This was also used for local access to the control systems for tests and development work (Annual Report 1981, p. 80, Fig. 10).

A System to Generate SignWriting for Video Tracks Enhancing Accessibility of Deaf People

OpenAIRE

Elena Verdú; Cristina Pelayo G-Bustelo; Ángeles Martínez Sánchez; Rubén Gonzalez-Crespo

2017-01-01

Video content has increased much on the Internet during last years. In spite of the efforts of different organizations and governments to increase the accessibility of websites, most multimedia content on the Internet is not accessible. This paper describes a system that contributes to make multimedia content more accessible on the Web, by automatically translating subtitles in oral language to Sign Writing, a way of writing Sign Language. This system extends the functionality of a general we...

Privacy and Access Control for IHE-Based Systems

Science.gov (United States)

Katt, Basel; Breu, Ruth; Hafner, Micahel; Schabetsberger, Thomas; Mair, Richard; Wozak, Florian

Electronic Health Record (EHR) is the heart element of any e-health system, which aims at improving the quality and efficiency of healthcare through the use of information and communication technologies. The sensitivity of the data contained in the health record poses a great challenge to security. In this paper we propose a security architecture for EHR systems that are conform with IHE profiles. In this architecture we are tackling the problems of access control and privacy. Furthermore, a prototypical implementation of the proposed model is presented.

Bus Access Optimisation for FlexRay-based Distributed Embedded Systems

DEFF Research Database (Denmark)

Pop, Traian; Pop, Paul; Eles, Petru

2007-01-01

-real time communication in a deterministic manner. In this paper, we propose techniques for optimising the FlexRay bus access mechanism of a distributed system, so that the hard real-time deadlines are met for all the tasks and messages in the system. We have evaluated the proposed techniques using...

Potential game theory applications in radio resource allocation

CERN Document Server

Lã, Quang Duy; Soong, Boon-Hee

2016-01-01

This book offers a thorough examination of potential game theory and its applications in radio resource management for wireless communications systems and networking. The book addresses two major research goals: how to identify a given game as a potential game, and how to design the utility functions and the potential functions with certain special properties in order to formulate a potential game. After proposing a unifying mathematical framework for the identification of potential games, the text surveys existing applications of this technique within wireless communications and networking problems found in OFDMA 3G/4G/WiFi networks, as well as next-generation systems such as cognitive radios and dynamic spectrum access networks. Professionals interested in understanding the theoretical aspect of this specialized field will find Potential Game Theory a valuable resource, as will advanced-level engineering students. It paves the way for extensive and rigorous research exploration on a topic whose capacity for...

A novel technique to extract events from access control system and locate persons

International Nuclear Information System (INIS)

Vincent, M.; Vaidyanathan, Mythili; Patidar, Suresh Chandra; Prabhakara Rao, G.

2011-01-01

Indira Gandhi Centre for Atomic Research houses many laboratories which handle radioactive materials and classified materials. Protection and accounting of men and material and critical facilities are important aspect of nuclear security. Access Control System (ACS) is used to enhance the protective measures against elevated threat environment. Access control system hardware consists of hand geometry readers, RFID readers, Controllers, Electromagnetic door locks, Turnstiles, fiber cable laying and termination etc. Access Control System controls and monitors the people accessing the secured facilities. Access Control System generates events on: 1. Showing of RFID card, 2. Rotation of turnstile, 3. Download of valid card numbers, 4. Generation of alarms etc. Access control system turnstiles are located in main entrance of a facility, entrance of inside laboratory and door locks are fixed on secured facilities. Events are stored in SQL server database. From the events stored in database a novel technique is developed to extract events and list the persons in a particular facility, list all entry/exit events on one day, list the first in and last out entries. This paper discusses the complex multi level group by queries and software developed to extract events from database, locate persons and generate reports. Software is developed as a web application in ASP.Net and query is written in SQL. User can select the doors, type of events and generate reports. Reports are generated using the master data stored about employees RFID cards and events data stored in tables. Four types of reports are generated 1. Plant Emergency Report, 2. Locate User Report, 3. Entry - Exit Report, 4. First in Last out Report. To generate plant emergency report for whole plant only events generated in outer gates have to be considered. To generate plant emergency report for inside laboratory, events generated in entrance gates have to be ignored. (author)

Interference Coordination for E-MBMS Transmissions in LTE-Advanced

Directory of Open Access Journals (Sweden)

Alberto A. Lopes

2010-01-01

Full Text Available Interference coordination methods for Evolved-Multimedia Broadcast/Multicast Service (E-MBMS in Long-Term Evolution Advanced (LTE-A are presented. In addition, we consider signal space diversity based on Rotation Matrices (RM known to provide good performance gains over uncorrelated Rayleigh fading channels. OFDM/OFDMA systems can make the use of RM very attractive both for single and multiple antenna transmissions. In this paper, OFDM/OFDMA signals based on LTE parameters are combined with RM, MIMO, Turbo, or LDPC codes. We have considered different types of receivers, namely, we used an MMSE (Minimum Mean Squared Error equalizer and a Maximum Likelihood Soft Output criterion (MLSO. Frequency, signal, and space diversity gains are evaluated for different spatial channel models (SCM based on ITU multipath propagation channels. Different adaptive frequency reuse and schedulers are considered to evaluate the E-MBMS spectral efficiency at the cell borders.

Design of pulse waveform for waveform division multiple access UWB wireless communication system.

Science.gov (United States)

Yin, Zhendong; Wang, Zhirui; Liu, Xiaohui; Wu, Zhilu

2014-01-01

A new multiple access scheme, Waveform Division Multiple Access (WDMA) based on the orthogonal wavelet function, is presented. After studying the correlation properties of different categories of single wavelet functions, the one with the best correlation property will be chosen as the foundation for combined waveform. In the communication system, each user is assigned to different combined orthogonal waveform. Demonstrated by simulation, combined waveform is more suitable than single wavelet function to be a communication medium in WDMA system. Due to the excellent orthogonality, the bit error rate (BER) of multiuser with combined waveforms is so close to that of single user in a synchronous system. That is to say, the multiple access interference (MAI) is almost eliminated. Furthermore, even in an asynchronous system without multiuser detection after matched filters, the result is still pretty ideal and satisfactory by using the third combination mode that will be mentioned in the study.

Embedded systems for supporting computer accessibility.

Science.gov (United States)

Mulfari, Davide; Celesti, Antonio; Fazio, Maria; Villari, Massimo; Puliafito, Antonio

2015-01-01

Nowadays, customized AT software solutions allow their users to interact with various kinds of computer systems. Such tools are generally available on personal devices (e.g., smartphones, laptops and so on) commonly used by a person with a disability. In this paper, we investigate a way of using the aforementioned AT equipments in order to access many different devices without assistive preferences. The solution takes advantage of open source hardware and its core component consists of an affordable Linux embedded system: it grabs data coming from the assistive software, which runs on the user's personal device, then, after processing, it generates native keyboard and mouse HID commands for the target computing device controlled by the end user. This process supports any operating system available on the target machine and it requires no specialized software installation; therefore the user with a disability can rely on a single assistive tool to control a wide range of computing platforms, including conventional computers and many kinds of mobile devices, which receive input commands through the USB HID protocol.

A Comprehensive System for Monitoring Urban Accessibility in Smart Cities.

Science.gov (United States)

Mora, Higinio; Gilart-Iglesias, Virgilio; Pérez-Del Hoyo, Raquel; Andújar-Montoya, María Dolores

2017-08-09

The present work discusses the possibilities offered by the evolution of Information and Communication Technologies with the aim of designing a system to dynamically obtain knowledge of accessibility issues in urban environments. This system is facilitated by technology to analyse the urban user experience and movement accessibility, which enabling accurate identification of urban barriers and monitoring its effectiveness over time. Therefore, the main purpose of the system is to meet the real needs and requirements of people with movement disabilities. The information obtained can be provided as a support service for decision-making to be used by city government, institutions, researchers, professionals and other individuals of society in general to improve the liveability and quality of the lives of citizens. The proposed system is a means of social awareness that makes the most vulnerable groups of citizens visible by involving them as active participants. To perform and implement the system, the latest communication and positioning technologies for smart sensing have been used, as well as the cloud computing paradigm. Finally, to validate the proposal, a case study has been presented using the university environment as a pre-deployment step in urban environments.

Open-Access, Low-Magnetic-Field MRI System for Lung Research

Science.gov (United States)

Mair, Ross W.; Rosen, Matthew S.; Tsai, Leo L.; Walsworth, Ronald L.; Hrovat, Mirko I.; Patz, Samuel; Ruset, Iullian C.; Hersman, F. William

2009-01-01

An open-access magnetic resonance imaging (MRI) system is being developed for use in research on orientational/gravitational effects on lung physiology and function. The open-access geometry enables study of human subjects in diverse orientations. This system operates at a magnetic flux density, considerably smaller than the flux densities of typical other MRI systems, that can be generated by resistive electromagnet coils (instead of the more-expensive superconducting coils of the other systems). The human subject inhales air containing He-3 or Xe-129 atoms, the nuclear spins of which have been polarized by use of a laser beam to obtain a magnetic resonance that enables high-resolution gas space imaging at the low applied magnetic field. The system includes a bi-planar, constant-current, four-coil electromagnet assembly and associated electronic circuitry to apply a static magnetic field of 6.5 mT throughout the lung volume; planar coils and associated circuitry to apply a pulsed magnetic-field-gradient for each spatial dimension; a single, detachable radio-frequency coil and associated circuitry for inducing and detecting MRI signals; a table for supporting a horizontal subject; and electromagnetic shielding surrounding the electromagnet coils.

A Multistage Decision-Feedback Receiver Design for LTE Uplink in Mobile Time-Variant Environments

Directory of Open Access Journals (Sweden)

Juinn-Horng Deng

2012-01-01

Full Text Available Single-carrier-frequency division multiple access (SC-FDMA has recently become the preferred uplink transmission scheme in long-term evolution (LTE systems. Similar to orthogonal frequency division multiple access (OFDMA, SC-FDMA is highly sensitive to frequency offsets caused by oscillator inaccuracies and Doppler spread, which lead to intercarrier interference (ICI. This work proposes a multistage decision-feedback structure to mitigate the ICI effect and enhance system performance in time-variant environments. Based on the block-type pilot arrangement of the LTE uplink type 1 frame structure, the time-domain least squares (TDLS method and polynomial-based curve-fitting algorithm are employed for channel estimation. Instead of using a conventional equalizer, this work uses a group frequency-domain equalizer (GFDE to reduce computational complexity. Furthermore, this work utilizes a dual iterative structure of group parallel interference cancellation (GPIC and frequency-domain group parallel interference cancellation (FPIC to mitigate the ICI effect. Finally, to optimize system performance, this work applies a novel error-correction scheme. Simulation results demonstrate the bit error rate (BER performance is markedly superior to that of the conventional full-size receiver based on minimum mean square error (MMSE. This structure performs well and is a flexible choice in mobile environments using the SC-FDMA scheme.

Does the public deserve free access to climate system science?

Science.gov (United States)

Grigorov, Ivo

2010-05-01

Some time ago it was the lack of public access to medical research data that really stirred the issue and gave inertia for legislation and a new publishing model that puts tax payer-funded medical research in the hands of those who fund it. In today's age global climate change has become the biggest socio-economic challenge, and the same argument resonates: climate affects us all and the publicly-funded science quantifying it should be freely accessible to all stakeholders beyond academic research. Over the last few years the ‘Open Access' movement to remove as much as possible subscription, and other on-campus barriers to academic research has rapidly gathered pace, but despite significant progress, the climate system sciences are not among the leaders in providing full access to their publications and data. Beyond the ethical argument, there are proven and tangible benefits for the next generation of climate researchers to adapt the way their output is published. Through the means provided by ‘open access', both data and ideas can gain more visibility, use and citations for the authors, but also result in a more rapid exchange of knowledge and ideas, and ultimately progress towards a sought solution. The presentation will aim to stimulate discussion and seek progress on the following questions: Should free access to climate research (& data) be mandatory? What are the career benefits of using ‘open access' for young scientists? What means and methods should, or could, be incorporated into current European graduate training programmes in climate research, and possible ways forward?

78 FR 43963 - Twenty-Third Meeting: RTCA Special Committee 224, Airport Security Access Control Systems

Science.gov (United States)

2013-07-22

... Committee 224, Airport Security Access Control Systems AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Meeting Notice of RTCA Special Committee 224, Airport Security... meeting of the RTCA Special Committee 224, Airport Security Access Control Systems. DATES: The meeting...

A Rewritable, Random-Access DNA-Based Storage System.

Science.gov (United States)

Yazdi, S M Hossein Tabatabaei; Yuan, Yongbo; Ma, Jian; Zhao, Huimin; Milenkovic, Olgica

2015-09-18

We describe the first DNA-based storage architecture that enables random access to data blocks and rewriting of information stored at arbitrary locations within the blocks. The newly developed architecture overcomes drawbacks of existing read-only methods that require decoding the whole file in order to read one data fragment. Our system is based on new constrained coding techniques and accompanying DNA editing methods that ensure data reliability, specificity and sensitivity of access, and at the same time provide exceptionally high data storage capacity. As a proof of concept, we encoded parts of the Wikipedia pages of six universities in the USA, and selected and edited parts of the text written in DNA corresponding to three of these schools. The results suggest that DNA is a versatile media suitable for both ultrahigh density archival and rewritable storage applications.

The assessment of exploitation process of power for access control system

Science.gov (United States)

Wiśnios, Michał; Paś, Jacek

2017-10-01

The safety of public utility facilities is a function not only of effectiveness of the electronic safety systems, used for protection of property and persons, but it also depends on the proper functioning of their power supply systems. The authors of the research paper analysed the power supply systems, which are used in buildings for the access control system that is integrated with the closed-circuit TV. The Access Control System is a set of electronic, electromechanical and electrical devices and the computer software controlling the operation of the above-mentioned elements, which is aimed at identification of people, vehicles allowed to cross the boundary of the reserved area, to prevent from crossing the reserved area and to generate the alarm signal informing about the attempt of crossing by an unauthorised entity. The industrial electricity with appropriate technical parameters is a basis of proper functioning of safety systems. Only the electricity supply to the systems is not equivalent to the operation continuity provision. In practice, redundant power supply systems are used. In the carried out reliability analysis of the power supply system, various power circuits of the system were taken into account. The reliability and operation requirements for this type of system were also included.

Seed quality of common bean accessions under organic and conventional farming systems

Directory of Open Access Journals (Sweden)

Diego Medeiros Gindri

2017-06-01

Full Text Available Agrobiodiversity is essential for a sustainable food production, and the knowledge of the potential characteristics of landrace seeds may prompt farmers to adopt the habit of seed conservation for this species. This study aimed at categorizing landrace and commercial common bean (Phaseolus vulgaris L. accessions, according to the physiological quality (viability and vigor of seeds produced in the field, during two growing seasons, under organic and conventional farming systems. Germination percentage, field emergence, electrical conductivity, accelerated aging, cold test and seedling length were assessed. The landrace bean accessions exhibit diversity in the physiological seed quality, in terms of their viability and vigor. No differences were observed between the farming systems, in relation to the physiological quality of the seeds produced. The categorization of landrace common bean accessions allows to identify those with superior physiological seed quality.

Evaluasi Pemanfaatan Wireless Internet Protocol Access System di Kota Malang

Directory of Open Access Journals (Sweden)

Ahmad Budi Setiawan

2012-03-01

Full Text Available WIPAS (Wireless Internet Protocol Accsess System adalah salah satu teknologi pita lebar (broadband yang terbaru. Teknologi tersebut dikembangkan berdasarkan model point-to-multipoint access system pada jaringan nirkabel tetap atau Fixed Wireless Access (FWA dengan memanfaatkan pita frekuensi 26-GHz. Dengan besarnya pita frekuensi yang digunakan, teknologi WIPAS dapat menampung kapasitas akses untuk lalu lintas jaringan yang sangat besar. Dalam penelitian ini akan dikaji dan dievaluasi efektifitas penggunaan teknologi WIPAS melalui kasus pemanfaatan teknologi WIPAS untuk pemberdayaan komunitas di kota Malang. Dalam penelitian ini juga akan dideskripsikan pemanfaatan teknologi WIPAS untuk melihat manfaat penggunaan teknologi tersebut. Penelitian ini dilakukan dengan metode kualitatif dengan melakukan evaluasi terhadap infrastruktur yang telah dibangun untuk melihat efektifitas pemanfaatan WIPAS. Hasil penelitian ini adalah sebuah kajian evaluatif tentang pemanfaatan WIPAS di kota Malang dan rekomendasi untuk implementasi lebih lanjut.

An end-to-end secure patient information access card system.

Science.gov (United States)

Alkhateeb, A; Singer, H; Yakami, M; Takahashi, T

2000-03-01

The rapid development of the Internet and the increasing interest in Internet-based solutions has promoted the idea of creating Internet-based health information applications. This will force a change in the role of IC cards in healthcare card systems from a data carrier to an access key medium. At the Medical Informatics Department of Kyoto University Hospital we are developing a smart card patient information project where patient databases are accessed via the Internet. Strong end-to-end data encryption is performed via Secure Socket Layers, transparent to transmit patient information. The smart card is playing the crucial role of access key to the database: user authentication is performed internally without ever revealing the actual key. For easy acceptance by healthcare professionals, the user interface is integrated as a plug-in for two familiar Web browsers, Netscape Navigator and MS Internet Explorer.

Presidential Management Fellows (PMF) Talent Acquisition System, PMF-TAS (ACCESS CONTROLLED)

Data.gov (United States)

Office of Personnel Management — Application and Assessment system for Presidential Management Fellows (PMF) and PMF Science, Technology, Engineering, and Math (STEM) programs. This sytem is access...

28 CFR 16.72 - Exemption of Office of the Associate Attorney General System-limited access.

Science.gov (United States)

2010-07-01

... Attorney General System-limited access. 16.72 Section 16.72 Judicial Administration DEPARTMENT OF JUSTICE....72 Exemption of Office of the Associate Attorney General System—limited access. (a) The following...) General Files System of the Office of the Associate Attorney General (JUSTICE/AAG-001). These exemptions...

TECHNOLOGY FOR ADMINISTERING OF THE ACCESS TO INFORMATION RESOURCES IN MANAGEMENT SYSTEM ON THE AVIATION ENTERPRISE

Directory of Open Access Journals (Sweden)

Andrey V. Degtyarev

2015-01-01

Full Text Available The task of administering software-information complex occurs duringthe development of application systems for managing business-processes and is connected with the organization of access forusers to information resources in conditions of multi-user information systems for management. For solution of this problem proposed theapproach, which is based on a hierarchical system of access rightsto information resources on the levels: tool, object and procedural.Keywords: software-information complex, information resources,administering, permissions, separation of powers, access model.

Access to Justice in the European Convention on Human Rights System

NARCIS (Netherlands)

Glas, L.R.; Gerards, J.H.

2017-01-01

The numerous reforms to the Convention system of the past two decades have unquestionably had an effect on applicants’ means to access justice in the system. It is, however, open to question how these changes should be evaluated: with reference to the individual right to petition, or with reference

Propagation Characteristics in an Underground Shopping Area for 5GHz-band Wireless Access Systems

Science.gov (United States)

Itokawa, Kiyohiko; Kita, Naoki; Sato, Akio; Matsue, Hideaki; Mori, Daisuke; Watanabe, Hironobu

5-GHz band wireless access systems, such as the RLAN (Radio Local Area Network) system of IEEE802.11a, HiperLAN/2, HiSWANa and AWA, are developed and provide transmission rates over 20 Mbps for indoor use. Those 5-GHz access systems are expected to extend service areas from the office to the so-called “hot-spot" in public areas. Underground shopping malls are one of the anticipated service areas for such a nomadic wireless access service. Broadband propagation characteristics are required for radio zone design in an underground mall environment despite previous results obtained by narrow band measurements. This paper presents results of an experimental study on the propagation characteristics for broadband wireless access systems in an underground mall environment. First, broadband propagation path loss is measured and formulated considering human body shadowing. A ray trace simulation is used to clarify the basic propagation mechanism in such a closed environment. Next, a distance dependency of the delay spread during a crowded time period, rush hour, is found to be at most 65 nsec, which is under the permitted maximum value of the present 5-GHz systems. Finally, above propagation characteristics support the result of transmission test carried out by using AWA equipment.

On board processing for future satellite communications systems: Comparison of FDM, TDM and hybrid accessing schemes

Science.gov (United States)

Berk, G.; Jean, P. N.; Rotholz, E.

1982-01-01

Several satellite uplink and downlink accessing schemes for customer premises service are compared. Four conceptual system designs are presented: satellite-routed frequency division multiple access (FDMA), satellite-switched time division multiple access (TDMA), processor-routed TDMA, and frequency-routed TDMA, operating in the 30/20 GHz band. The designs are compared on the basis of estimated satellite weight, system capacity, power consumption, and cost. The systems are analyzed for fixed multibeam coverage of the continental United States. Analysis shows that the system capacity is limited by the available satellite resources and by the terminal size and cost.

Information system architecture to support transparent access to distributed, heterogeneous data sources

International Nuclear Information System (INIS)

Brown, J.C.

1994-08-01

Quality situation assessment and decision making require access to multiple sources of data and information. Insufficient accessibility to data exists for many large corporations and Government agencies. By utilizing current advances in computer technology, today's situation analyst's have a wealth of information at their disposal. There are many potential solutions to the information accessibility problem using today's technology. The United States Department of Energy (US-DOE) faced this problem when dealing with one class of problem in the US. The result of their efforts has been the creation of the Tank Waste Information Network System -- TWINS. The TWINS solution combines many technologies to address problems in several areas such as User Interfaces, Transparent Access to Multiple Data Sources, and Integrated Data Access. Data related to the complex is currently distributed throughout several US-DOE installations. Over time, each installation has adopted their own set of standards as related to information management. Heterogeneous hardware and software platforms exist both across the complex and within a single installation. Standards for information management vary between US-DOE mission areas within installations. These factors contribute to the complexity of accessing information in a manner that enhances the performance and decision making process of the analysts. This paper presents one approach taken by the DOE to resolve the problem of distributed, heterogeneous, multi-media information management for the HLW Tank complex. The information system architecture developed for the DOE by the TWINS effort is one that is adaptable to other problem domains and uses

GP preferences for information systems: conjoint analysis of speed, reliability, access and users.

Science.gov (United States)

Wyatt, Jeremy C; Batley, Richard P; Keen, Justin

2010-10-01

To elicit the preferences and trade-offs of UK general practitioners about key features of health information systems, to help inform the design of such systems in future. A stated choice study to uncover implicit preferences based on a binary choice between scenarios presented in random order. were all 303 general practice members of the UK Internet service provider, Medix who were approached by email to participate. The main outcome measure was the number of seconds delay in system response that general practitioners were willing to trade off for each key system feature: the reliability of the system, the sites from which the system could be accessed and which staff are able to view patient data. Doctors valued speed of response most in information systems but would be prepared to wait 28 seconds to access a system in exchange for improved reliability from 95% to 99%, a further 2 seconds for an improvement to 99.9% and 27 seconds for access to data from anywhere including their own home compared with one place in a single health care premises. However, they would require a system that was 14 seconds faster to compensate for allowing social care as well as National Health Service staff to read patient data. These results provide important new evidence about which system characteristics doctors value highly, and hence which characteristics designers need to focus on when large scale health information systems are planned. © 2010 Blackwell Publishing Ltd.

28 CFR 16.83 - Exemption of the Executive Office for Immigration Review System-limited access.

Science.gov (United States)

2010-07-01

... Immigration Review System-limited access. 16.83 Section 16.83 Judicial Administration DEPARTMENT OF JUSTICE....83 Exemption of the Executive Office for Immigration Review System—limited access. (a) The following system of records is exempt from 5 U.S.C. 552a(d): (1) The Executive Office for Immigration Review's...

Multiple Access Interference Reduction Using Received Response Code Sequence for DS-CDMA UWB System

Science.gov (United States)

Toh, Keat Beng; Tachikawa, Shin'ichi

This paper proposes a combination of novel Received Response (RR) sequence at the transmitter and a Matched Filter-RAKE (MF-RAKE) combining scheme receiver system for the Direct Sequence-Code Division Multiple Access Ultra Wideband (DS-CDMA UWB) multipath channel model. This paper also demonstrates the effectiveness of the RR sequence in Multiple Access Interference (MAI) reduction for the DS-CDMA UWB system. It suggests that by using conventional binary code sequence such as the M sequence or the Gold sequence, there is a possibility of generating extra MAI in the UWB system. Therefore, it is quite difficult to collect the energy efficiently although the RAKE reception method is applied at the receiver. The main purpose of the proposed system is to overcome the performance degradation for UWB transmission due to the occurrence of MAI during multiple accessing in the DS-CDMA UWB system. The proposed system improves the system performance by improving the RAKE reception performance using the RR sequence which can reduce the MAI effect significantly. Simulation results verify that significant improvement can be obtained by the proposed system in the UWB multipath channel models.

Digital Autonomous Terminal Access Communication (DATAC) system

Science.gov (United States)

Novacki, Stanley M., III

1987-01-01

In order to accommodate the increasing number of computerized subsystems aboard today's more fuel efficient aircraft, the Boeing Co. has developed the DATAC (Digital Autonomous Terminal Access Control) bus to minimize the need for point-to-point wiring to interconnect these various systems, thereby reducing total aircraft weight and maintaining an economical flight configuration. The DATAC bus is essentially a local area network providing interconnections for any of the flight management and control systems aboard the aircraft. The task of developing a Bus Monitor Unit was broken down into four subtasks: (1) providing a hardware interface between the DATAC bus and the Z8000-based microcomputer system to be used as the bus monitor; (2) establishing a communication link between the Z8000 system and a CP/M-based computer system; (3) generation of data reduction and display software to output data to the console device; and (4) development of a DATAC Terminal Simulator to facilitate testing of the hardware and software which transfer data between the DATAC's bus and the operator's console in a near real time environment. These tasks are briefly discussed.

ACCESS Sub-system Performance

Science.gov (United States)

Kaiser, Mary Elizabeth; Morris, Matthew J.; Aldoroty, Lauren Nicole; Godon, David; Pelton, Russell; McCandliss, Stephan R.; Kurucz, Robert L.; Kruk, Jeffrey W.; Rauscher, Bernard J.; Kimble, Randy A.; Wright, Edward L.; Benford, Dominic J.; Gardner, Jonathan P.; Feldman, Paul D.; Moos, H. Warren; Riess, Adam G.; Bohlin, Ralph; Deustua, Susana E.; Dixon, William Van Dyke; Sahnow, David J.; Lampton, Michael; Perlmutter, Saul

2016-01-01

ACCESS: Absolute Color Calibration Experiment for Standard Stars is a series of rocket-borne sub-orbital missions and ground-based experiments designed to leverage significant technological advances in detectors, instruments, and the precision of the fundamental laboratory standards used to calibrate these instruments to enable improvements in the precision of the astrophysical flux scale through the transfer of laboratory absolute detector standards from the National Institute of Standards and Technology (NIST) to a network of stellar standards with a calibration accuracy of 1% and a spectral resolving power of 500 across the 0.35 to 1.7 micron bandpass.A cross wavelength calibration of the astrophysical flux scale to this level of precision over this broad a bandpass is relevant for the data used to probe fundamental astrophysical problems such as the SNeIa photometry based measurements used to constrain dark energy theories.We will describe the strategy for achieving this level of precision, the payload and calibration configuration, present sub-system test data, and the status and preliminary performance of the integration and test of the spectrograph and telescope. NASA APRA sounding rocket grant NNX14AH48G supports this work.

Design mobile satellite system architecture as an integral part of the cellular access digital network

Science.gov (United States)

Chien, E. S. K.; Marinho, J. A.; Russell, J. E., Sr.

1988-01-01

The Cellular Access Digital Network (CADN) is the access vehicle through which cellular technology is brought into the mainstream of the evolving integrated telecommunications network. Beyond the integrated end-to-end digital access and per call network services provisioning of the Integrated Services Digital Network (ISDN), the CADN engenders the added capability of mobility freedom via wireless access. One key element of the CADN network architecture is the standard user to network interface that is independent of RF transmission technology. Since the Mobile Satellite System (MSS) is envisioned to not only complement but also enhance the capabilities of the terrestrial cellular telecommunications network, compatibility and interoperability between terrestrial cellular and mobile satellite systems are vitally important to provide an integrated moving telecommunications network of the future. From a network standpoint, there exist very strong commonalities between the terrestrial cellular system and the mobile satellite system. Therefore, the MSS architecture should be designed as an integral part of the CADN. This paper describes the concept of the CADN, the functional architecture of the MSS, and the user-network interface signaling protocols.

Impact of optical hard limiter on the performance of an optical overlapped-code division multiple access system

Science.gov (United States)

Inaty, Elie; Raad, Robert; Tablieh, Nicole

2011-08-01

Throughout this paper, a closed form expression of the multiple access interference (MAI) limited bit error rate (BER) is provided for the multiwavelength optical code-division multiple-access system when the system is working above the nominal transmission rate limit imposed by the passive encoding-decoding operation. This system is known in literature as the optical overlapped code division multiple access (OV-CDMA) system. A unified analytical framework is presented emphasizing the impact of optical hard limiter (OHL) on the BER performance of such a system. Results show that the performance of the OV-CDMA system may be highly improved when using OHL preprocessing at the receiver side.

Broadband and scalable mobile satellite communication system for future access networks

Science.gov (United States)

Ohata, Kohei; Kobayashi, Kiyoshi; Nakahira, Katsuya; Ueba, Masazumi

2005-07-01

Due to the recent market trends, NTT has begun research into next generation satellite communication systems, such as broadband and scalable mobile communication systems. One service application objective is to provide broadband Internet access for transportation systems, temporal broadband access networks and telemetries to remote areas. While these are niche markets the total amount of capacity should be significant. We set a 1-Gb/s total transmission capacity as our goal. Our key concern is the system cost, which means that the system should be unified system with diversified services and not tailored for each application. As satellites account for a large portion of the total system cost, we set the target satellite size as a small, one-ton class dry mass with a 2-kW class payload power. In addition to the payload power and weight, the mobile satellite's frequency band is extremely limited. Therefore, we need to develop innovative technologies that will reduce the weight and maximize spectrum and power efficiency. Another challenge is the need for the system to handle up to 50 dB and a wide data rate range of other applications. This paper describes the key communication system technologies; the frequency reuse strategy, multiplexing scheme, resource allocation scheme, and QoS management algorithm to ensure excellent spectrum efficiency and support a variety of services and quality requirements in the mobile environment.

Peripheral Insertion of a Central Venous Access Device Under Fluoroscopic Guidance Using a Peripherally Accessed System (PAS) Port in the Forearm

International Nuclear Information System (INIS)

Hata, Yasuhiro; Morita, Sojiro; Morita, Yoshitaka; Awatani, Toshihide; Takasaki, Motohiro; Horimi, Tadashi; Ozawa, Zen

1998-01-01

Purpose: We describe the technique, efficacy, and complications of fluoroscopy-guided implantation of a central venous access device using a peripherally accessed system (PAS) port via the forearm. Methods: Beginning in July 1994, 105 central venous access devices were implanted in 104 patients for the long-term infusion of antibiotics or antineoplasmic agents, blood products, or parenteral nutrition. The devices was inserted under fluoroscopic guidance with real-time venography from a peripheral route. Results: All ports were successfully implanted. There were no procedure-related complications. No thrombosis or local infection was observed; however, in six patients catheter-related phlebitis occurred. Conclusion: Fluoroscopy-guided implantation of a central venous access device using a PAS port via the forearm is safe and efficacious, and injection of contrast medium through a peripheral IV catheter before introduction of the catheter helps to avoid catheter-related phlebitis

Code division multiple-access techniques in optical fiber networks. II - Systems performance analysis

Science.gov (United States)

Salehi, Jawad A.; Brackett, Charles A.

1989-08-01

A technique based on optical orthogonal codes was presented by Salehi (1989) to establish a fiber-optic code-division multiple-access (FO-CDMA) communications system. The results are used to derive the bit error rate of the proposed FO-CDMA system as a function of data rate, code length, code weight, number of users, and receiver threshold. The performance characteristics for a variety of system parameters are discussed. A means of reducing the effective multiple-access interference signal by placing an optical hard-limiter at the front end of the desired optical correlator is presented. Performance calculations are shown for the FO-CDMA with an ideal optical hard-limiter, and it is shown that using a optical hard-limiter would, in general, improve system performance.

Generation-based memory synchronization in a multiprocessor system with weakly consistent memory accesses

Energy Technology Data Exchange (ETDEWEB)

Ohmacht, Martin

2017-08-15

In a multiprocessor system, a central memory synchronization module coordinates memory synchronization requests responsive to memory access requests in flight, a generation counter, and a reclaim pointer. The central module communicates via point-to-point communication. The module includes a global OR reduce tree for each memory access requesting device, for detecting memory access requests in flight. An interface unit is implemented associated with each processor requesting synchronization. The interface unit includes multiple generation completion detectors. The generation count and reclaim pointer do not pass one another.

Generation-based memory synchronization in a multiprocessor system with weakly consistent memory accesses

Science.gov (United States)

Ohmacht, Martin

2014-09-09

In a multiprocessor system, a central memory synchronization module coordinates memory synchronization requests responsive to memory access requests in flight, a generation counter, and a reclaim pointer. The central module communicates via point-to-point communication. The module includes a global OR reduce tree for each memory access requesting device, for detecting memory access requests in flight. An interface unit is implemented associated with each processor requesting synchronization. The interface unit includes multiple generation completion detectors. The generation count and reclaim pointer do not pass one another.

Access Denied! Contrasting Data Access in the United States and Ireland

Directory of Open Access Journals (Sweden)

Grogan Samuel

2016-07-01

Full Text Available The ability of an Internet user to access data collected about himself as a result of his online activity is a key privacy safeguard. Online, data access has been overshadowed by other protections such as notice and choice. This paper describes attitudes about data access. 873 US and Irish Internet users participated in a survey designed to examine views on data access to information held by online companies and data brokers. We observed low levels of awareness of access mechanisms along with a high desire for access in both participant groups. We tested three proposed access systems in keeping with industry programs and regulatory proposals. User response was positive. We conclude that access remains an important privacy protection that is inadequately manifested in practice. Our study provides insight for lawmakers and policymakers, as well as computer scientists who implement these systems.

A Novel Medium Access Control for Ad hoc Networks Based on OFDM System

Institute of Scientific and Technical Information of China (English)

YU Yi-fan; YIN Chang-chuan; YUE Guang-xin

2005-01-01

Recently, hosts of Medium Access Control (MAC) protocols for Ad hoc radio networks have been proposed to solve the hidden terminal problem and exposed terminal problem. However most of them take into no account the interactions between physical (PHY) system and MAC protocol. Therefore, the current MAC protocols are either inefficient in the networks with mobile nodes and fading channel or difficult in hardware implementation. In this paper, we present a novel media access control for Ad hoc networks that integrates a media access control protocol termed as Dual Busy Tone Multiple Access (DBTMA) into Orthogonal Frequency Division Multiplexing (OFDM) system proposed in IEEE 802.11a standard. The analysis presented in the paper indicates that the proposed MAC scheme achieves performance improvement over IEEE 802.11 protocol about 25%～80% especially in the environment with high mobility and deep fading. The complexity of the proposed scheme is also lower than other implementation of similar busy tone solution. Furthermore, it is compatible with IEEE 802.11a networks.

Health Information System Role-Based Access Control Current Security Trends and Challenges.

Science.gov (United States)

de Carvalho Junior, Marcelo Antonio; Bandiera-Paiva, Paulo

2018-01-01

This article objective is to highlight implementation characteristics, concerns, or limitations over role-based access control (RBAC) use on health information system (HIS) using industry-focused literature review of current publishing for that purpose. Based on the findings, assessment for indication of RBAC is obsolete considering HIS authorization control needs. We have selected articles related to our investigation theme "RBAC trends and limitations" in 4 different sources related to health informatics or to the engineering technical field. To do so, we have applied the following search query string: "Role-Based Access Control" OR "RBAC" AND "Health information System" OR "EHR" AND "Trends" OR "Challenges" OR "Security" OR "Authorization" OR "Attacks" OR "Permission Assignment" OR "Permission Relation" OR "Permission Mapping" OR "Constraint". We followed PRISMA applicable flow and general methodology used on software engineering for systematic review. 20 articles were selected after applying inclusion and exclusion criteria resulting contributions from 10 different countries. 17 articles advocate RBAC adaptations. The main security trends and limitations mapped were related to emergency access, grant delegation, and interdomain access control. Several publishing proposed RBAC adaptations and enhancements in order to cope current HIS use characteristics. Most of the existent RBAC studies are not related to health informatics industry though. There is no clear indication of RBAC obsolescence for HIS use.

An Intelligent System Proposal for Improving the Safety and Accessibility of Public Transit by Highway

Directory of Open Access Journals (Sweden)

Carmelo R. García

2015-08-01

Full Text Available The development of public transit systems that are accessible and safe for everyone, including people with special needs, is an objective that is justified from the civic and economic points of view. Unfortunately, public transit services are conceived for people who do not have reduced physical or cognitive abilities. In this paper, we present an intelligent public transit system by highway with the goal of facilitating access and improving the safety of public transit for persons with special needs. The system is deployed using components that are commonly available in transport infrastructure, e.g., sensors, mobile communications systems, and positioning systems. In addition, the system can operate in non-urban transport contexts, e.g., isolated rural areas, where the availability of basic infrastructure, such as electricity and communications infrastructures, is not always guaranteed. To construct the system, the principles and techniques of Ubiquitous Computing and Ambient Intelligence have been employed. To illustrate the utility of the system, two cases of services rendered by the system are described: the first case involves a surveillance system to guarantee accessibility at bus stops; the second case involves a route assistant for blind people.

The new biometric access control system resembles a big electronic eye. It will be used to control access to the LHC from 2007 onwards.

CERN Multimedia

Maximilien Brice

2006-01-01

The new LHC access control systems will soon be using the latest technology: optical recognition based on iris image data. In order to gain access to the tunnel it will be your eye, not your credentials that you'll be required to show! As of September, the entrance point at Point 8 should be the first to be fitted out with iris recognition equipment. The other access shafts will then gradually be equipped one by one.

An investigation of interference coordination in heterogeneous network for LTE-Advanced systems

Science.gov (United States)

Hasan, M. K.; Ismail, A. F.; H, Aisha-Hassan A.; Abdullah, Khaizuran; Ramli, H. A. M.

2013-12-01

The novel "femtocell" in Heterogeneous Network (HetNet) for LTE-Advanced (LTE-A) set-up will allow Malaysian wireless telecommunication operators (Maxis, Celcom, Digi, U-Mobile, P1, YTL and etc2.) to extend connectivity coverage where access would otherwise be limited or unavailable, particularly indoors of large building complexes. A femtocell is a small-sized cellular base station that encompasses all the functionality of a typical station. It therefore allows a simpler and self-contained deployment including private residences. For the Malaysian service providers, the main attractions of femtocell usage are the improvements to both coverage and capacity. The operators can provide a better service to end-users in turn reduce much of the agitations and complaints. There will be opportunity for new services at reduced cost. In addition, the operator not only benefits from the improved capacity and coverage but also can reduce both capital expenditure and operating expense i.e. alternative to brand new base station or macrocell installation. Interference is a key issue associated with femtocell development. There are a large number of issues associated with interference all of which need to be investigated, identified, quantified and solved. This is to ensure that the deployment of any femtocells will take place successfully. Among the most critical challenges in femtocell deployment is the interference between femtocell-to-macrocell and femtocell-to-femtocell in HetNets. In this paper, all proposed methods and algorithms will be investigated in the OFDMA femtocell system considering HetNet scenarios for LTE-A.

An investigation of interference coordination in heterogeneous network for LTE-Advanced systems

International Nuclear Information System (INIS)

Hasan, M K; Ismail, A F; Aisha-Hassan A H; Abdullah, Khaizuran; Ramli, H A M

2013-01-01

The novel ''femtocell'' in Heterogeneous Network (HetNet) for LTE-Advanced (LTE-A) set-up will allow Malaysian wireless telecommunication operators (Maxis, Celcom, Digi, U-Mobile, P1, YTL and etc2.) to extend connectivity coverage where access would otherwise be limited or unavailable, particularly indoors of large building complexes. A femtocell is a small-sized cellular base station that encompasses all the functionality of a typical station. It therefore allows a simpler and self-contained deployment including private residences. For the Malaysian service providers, the main attractions of femtocell usage are the improvements to both coverage and capacity. The operators can provide a better service to end-users in turn reduce much of the agitations and complaints. There will be opportunity for new services at reduced cost. In addition, the operator not only benefits from the improved capacity and coverage but also can reduce both capital expenditure and operating expense i.e. alternative to brand new base station or macrocell installation. Interference is a key issue associated with femtocell development. There are a large number of issues associated with interference all of which need to be investigated, identified, quantified and solved. This is to ensure that the deployment of any femtocells will take place successfully. Among the most critical challenges in femtocell deployment is the interference between femtocell-to-macrocell and femtocell-to-femtocell in HetNets. In this paper, all proposed methods and algorithms will be investigated in the OFDMA femtocell system considering HetNet scenarios for LTE-A

Is the Japanese Distribution System Becoming More Accessible to Foreign Firms?

OpenAIRE

Ralf bebenroth; Nir Kshetri; Reinhard Hunerberg

2009-01-01

Complexities in the Japanese distribution system are well-publicized. An emerging body of literature has documented recent changes in the Japanese distribution system. In this paper, it is examined whether foreign firms' accessibility to the Japanese distribution system has changed in a favorable direction in recent years. Furthermore, as foreign firms vary widely in terms of institutional barriers and complexity they face in the Japanese market, the authors also investigate the determinants ...

National Geothermal Data System: an Exemplar of Open Access to Data

Science.gov (United States)

Allison, M. L.; Richard, S. M.; Blackman, H.; Anderson, A.

2013-12-01

The National Geothermal Data System's (NGDS - www.geothermaldata.org) formal launch in 2014 will provide open access to millions of datasets, sharing technical geothermal-relevant data across the geosciences to propel geothermal development and production. With information from all of the Department of Energy's sponsored development and research projects and geologic data from all 50 states, this free, interactive tool is opening new exploration opportunities and shortening project development by making data easily discoverable and accessible. We continue to populate our prototype functional data system with multiple data nodes and nationwide data online and available to the public. Data from state geological surveys and partners includes more than 5 million records online, including 1.48 million well headers (oil and gas, water, geothermal), 732,000 well logs, and 314,000 borehole temperatures and is growing rapidly. There are over 250 Web services and another 138 WMS (Web Map Services) registered in the system as of August, 2013. Companion projects run by Boise State University, Southern Methodist University, and USGS are adding millions of additional data records. The National Renewable Energy Laboratory is managing the Geothermal Data Repository which will serve as a system node and clearinghouse for data from hundreds of DOE-funded geothermal projects. NGDS is built on the US Geoscience Information Network data integration framework, which is a joint undertaking of the USGS and the Association of American State Geologists (AASG). NGDS is fully compliant with the White House Executive Order of May 2013, requiring all federal agencies to make their data holdings publicly accessible online in open source, interoperable formats with common core and extensible metadata. The National Geothermal Data System is being designed, built, deployed, and populated primarily with grants from the US Department of Energy, Geothermal Technologies Office. To keep this operational

Effects of Job Accessibility Improved by Public Transport System: Natural Experimental Evidence from the Copenhagen Metro

DEFF Research Database (Denmark)

Pons Rotger, Gabriel Angel; Nielsen, Thomas Alexander Sick

2015-01-01

This study examines the effect of accessibility to urban jobs via a public transport system on individual earnings and commuting behaviour. The effect of improved public transport based accessibility on these outcomes is determined by exploiting the exogenous variation in access to a public rail...... and Metro system resulting from the construction of a new terminal Metro station connecting southern townships to Copenhagen city centre. The results show that public transport based job accessibility has a positive and permanent effect on individual earnings. The increase in earnings is associated...... with a change in commuting patterns as the improved access to public transport facilitates a shift from employment within the township to better paid jobs in the city centre, as well as in other suburbs of the Copenhagen Metropolitan area...

Remotely Sensed Land Imagery and Access Systems: USGS Updates

Science.gov (United States)

Lamb, R.; Pieschke, R.; Lemig, K.

2017-12-01

The U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center has implemented a number of updates to its suite of remotely sensed products and distribution systems. These changes will greatly expand the availability, accessibility, and usability of the image products from USGS. As of late 2017, several new datasets are available for public download at no charge from USGS/EROS Center. These products include Multispectral Instrument (MSI) Level-1C data from the Sentinel-2B satellite, which was launched in March 2017. Along with Sentinel-2A, the Sentinel-2B images are now being distributed through USGS systems as part of a collaborative effort with the European Space Agency (ESA). The Sentinel-2 imagery is highly complementary to multispectral data collected by the USGS Landsat 7 and 8 satellites. With these two missions operating together, the potential local revisit rate can be reduced to 2-4 days. Another product addition is Resourcesat-2 data acquired over the United States by the Indian Space Research Organisation (ISRO). The Resourcesat-2 products from USGS consist of Advanced Wide Field Sensor (AWiFS) and Linear Imaging Self-Scanning Sensor Three (LISS-3) images acquired August 2016 to present. In an effort to maximize future Landsat data interoperability, including time series analysis of the 45+ year archive, the reprocessing of Collection 1 for all historical Landsat Level 1 products is nearly complete. The USGS is now working on operational release of higher-level science products to support analysis of the Landsat archive at the pixel level. Major upgrades were also completed in 2017 for several USGS data discovery and access systems, including the LandsatLook Viewer (https://landsatlook.usgs.gov/) and GloVis Tool (https://glovis.usgs.gov/). Other options are now being developed to further enhance data access and overall user experience. These future options will be discussed and community feedback will be encouraged.

Shared random access memory resource for multiprocessor real-time systems

International Nuclear Information System (INIS)

Dimmler, D.G.; Hardy, W.H. II

1977-01-01

A shared random-access memory resource is described which is used within real-time data acquisition and control systems with multiprocessor and multibus organizations. Hardware and software aspects are discussed in a specific example where interconnections are done via a UNIBUS. The general applicability of the approach is also discussed

A remark on accessibility

International Nuclear Information System (INIS)

Wu, Xinxing; Wang, Jianjun

2016-01-01

Highlights: • Obtain some characteristics of accessibility and Kato’s chaos. • Answer negatively a question in [Li R, Wang H, Zhao Y. Kato’s chaos in duopoly games. Chaos Solit Fract 2016;84:69–72]. • A dynamical system is indecomposable if and only if it is weakly transitive. - Abstract: This note obtains some characteristics of accessibility and Kato’s chaos. Applying these results, an accessible dynamical system whose product system is not accessible is constructed, giving a negative answer to a question in [Li R, Wang H, Zhao Y. Kato’s chaos in duopoly games. Chaos Solit Fract 2016;84:69–72]. Besides, it is proved that every transitive interval self-map is accessible.

Access Request Trustworthiness in Weighted Access Control Framework

Institute of Scientific and Technical Information of China (English)

WANG Lun-wei; LIAO Xiang-ke; WANG Huai-min

2005-01-01

Weighted factor is given to access control policies to express the importance of policy and its effect on access control decision. According to this weighted access control framework, a trustworthiness model for access request is also given. In this model, we give the measure of trustworthiness factor to access request, by using some idea of uncertainty reasoning of expert system, present and prove the parallel propagation formula of request trustworthiness factor among multiple policies, and get the final trustworthiness factor to decide whether authorizing. In this model, authorization decision is given according to the calculation of request trustworthiness factor, which is more understandable, more suitable for real requirement and more powerful for security enhancement than traditional methods. Meanwhile the finer access control granularity is another advantage.

Multiple Coaxial Catheter System for Reliable Access in Interventional Stroke Therapy

International Nuclear Information System (INIS)

Kulcsar, Zsolt; Yilmaz, Hasan; Bonvin, Christophe; Lovblad, Karl O.; Ruefenacht, Daniel A.

2010-01-01

In some patients with acute cerebral vessel occlusion, navigating mechanical thrombectomy systems is difficult due to tortuous anatomy of the aortic arch, carotid arteries, or vertebral arteries. Our purpose was to describe a multiple coaxial catheter system used for mechanical revascularization that helps navigation and manipulations in tortuous vessels. A triple or quadruple coaxial catheter system was built in 28 consecutive cases presenting with acute ischemic stroke. All cases were treated by mechanical thrombectomy with the Penumbra System. In cases of unsuccessful thrombo-aspiration, additional thrombolysis or angioplasty with stent placement was used for improving recanalization. The catheter system consisted of an outermost 8-Fr and an intermediate 6-Fr guiding catheter, containing the inner Penumbra reperfusion catheters. The largest, 4.1-Fr, reperfusion catheter was navigated over a Prowler Select Plus microcatheter. The catheter system provided access to reach the cerebral lesions and provided stability for the mechanically demanding manipulations of thromboaspiration and stent navigation in all cases. Apart from their mechanical role, the specific parts of the system could also provide access to different types of interventions, like carotid stenting through the 8-Fr guiding catheter and intracranial stenting and thrombolysis through the Prowler Select Plus microcatheter. In this series, there were no complications related to the catheter system. In conclusion, building up a triple or quadruple coaxial system proved to be safe and efficient in our experience for the mechanical thrombectomy treatment of acute ischemic stroke.

Interoperable Access to Near Real Time Ocean Observations with the Observing System Monitoring Center

Science.gov (United States)

O'Brien, K.; Hankin, S.; Mendelssohn, R.; Simons, R.; Smith, B.; Kern, K. J.

2013-12-01

The Observing System Monitoring Center (OSMC), a project funded by the National Oceanic and Atmospheric Administration's Climate Observations Division (COD), exists to join the discrete 'networks' of In Situ ocean observing platforms -- ships, surface floats, profiling floats, tide gauges, etc. - into a single, integrated system. The OSMC is addressing this goal through capabilities in three areas focusing on the needs of specific user groups: 1) it provides real time monitoring of the integrated observing system assets to assist management in optimizing the cost-effectiveness of the system for the assessment of climate variables; 2) it makes the stream of real time data coming from the observing system available to scientific end users into an easy-to-use form; and 3) in the future, it will unify the delayed-mode data from platform-focused data assembly centers into a standards- based distributed system that is readily accessible to interested users from the science and education communities. In this presentation, we will be focusing on the efforts of the OSMC to provide interoperable access to the near real time data stream that is available via the Global Telecommunications System (GTS). This is a very rich data source, and includes data from nearly all of the oceanographic platforms that are actively observing. We will discuss how the data is being served out using a number of widely used 'web services' (including OPeNDAP and SOS) and downloadable file formats (KML, csv, xls, netCDF), so that it can be accessed in web browsers and popular desktop analysis tools. We will also be discussing our use of the Environmental Research Division's Data Access Program (ERDDAP), available from NOAA/NMFS, which has allowed us to achieve our goals of serving the near real time data. From an interoperability perspective, it's important to note that access to the this stream of data is not just for humans, but also for machine-to-machine requests. We'll also delve into how we

ATLAS, an integrated structural analysis and design system. Volume 4: Random access file catalog

Science.gov (United States)

Gray, F. P., Jr. (Editor)

1979-01-01

A complete catalog is presented for the random access files used by the ATLAS integrated structural analysis and design system. ATLAS consists of several technical computation modules which output data matrices to corresponding random access file. A description of the matrices written on these files is contained herein.

First Experiences Using XACML for Access Control in Distributed Systems

Science.gov (United States)

Lorch, Marcus; Proctor, Seth; Lepro, Rebekah; Kafura, Dennis; Shah, Sumit

2003-01-01

Authorization systems today are increasingly complex. They span domains of administration, rely on many different authentication sources, and manage permissions that can be as complex as the system itself. Worse still, while there are many standards that define authentication mechanisms, the standards that address authorization are less well defined and tend to work only within homogeneous systems. This paper presents XACML, a standard access control language, as one component of a distributed and inter-operable authorization framework. Several emerging systems which incorporate XACML are discussed. These discussions illustrate how authorization can be deployed in distributed, decentralized systems. Finally, some new and future topics are presented to show where this work is heading and how it will help connect the general components of an authorization system.

Security Guidelines for the Development of Accessible Web Applications through the implementation of intelligent systems

Directory of Open Access Journals (Sweden)

Luis Joyanes Aguilar

2009-12-01

Full Text Available Due to the significant increase in threats, attacks and vulnerabilities that affect the Web in recent years has resulted the development and implementation of pools and methods to ensure security measures in the privacy, confidentiality and data integrity of users and businesses. Under certain circumstances, despite the implementation of these tools do not always get the flow of information which is passed in a secure manner. Many of these security tools and methods cannot be accessed by people who have disabilities or assistive technologies which enable people to access the Web efficiently. Among these security tools that are not accessible are the virtual keyboard, the CAPTCHA and other technologies that help to some extent to ensure safety on the Internet and are used in certain measures to combat malicious code and attacks that have been increased in recent times on the Web. Through the implementation of intelligent systems can detect, recover and receive information on the characteristics and properties of the different tools and hardware devices or software with which the user is accessing a web application and through analysis and interpretation of these intelligent systems can infer and automatically adjust the characteristics necessary to have these tools to be accessible by anyone regardless of disability or navigation context. This paper defines a set of guidelines and specific features that should have the security tools and methods to ensure the Web accessibility through the implementation of intelligent systems.

National Geothermal Data System: Open Access to Geoscience Data, Maps, and Documents

Science.gov (United States)

Caudill, C. M.; Richard, S. M.; Musil, L.; Sonnenschein, A.; Good, J.

2014-12-01

The U.S. National Geothermal Data System (NGDS) provides free open access to millions of geoscience data records, publications, maps, and reports via distributed web services to propel geothermal research, development, and production. NGDS is built on the US Geoscience Information Network (USGIN) data integration framework, which is a joint undertaking of the USGS and the Association of American State Geologists (AASG), and is compliant with international standards and protocols. NGDS currently serves geoscience information from 60+ data providers in all 50 states. Free and open source software is used in this federated system where data owners maintain control of their data. This interactive online system makes geoscience data easily discoverable, accessible, and interoperable at no cost to users. The dynamic project site http://geothermaldata.org serves as the information source and gateway to the system, allowing data and applications discovery and availability of the system's data feed. It also provides access to NGDS specifications and the free and open source code base (on GitHub), a map-centric and library style search interface, other software applications utilizing NGDS services, NGDS tutorials (via YouTube and USGIN site), and user-created tools and scripts. The user-friendly map-centric web-based application has been created to support finding, visualizing, mapping, and acquisition of data based on topic, location, time, provider, or key words. Geographic datasets visualized through the map interface also allow users to inspect the details of individual GIS data points (e.g. wells, geologic units, etc.). In addition, the interface provides the information necessary for users to access the GIS data from third party software applications such as GoogleEarth, UDig, and ArcGIS. A redistributable, free and open source software package called GINstack (USGIN software stack) was also created to give data providers a simple way to release data using

ICSW2AN : An Inter-vehicle Communication System Using Mobile Access Point over Wireless Wide Area Networks

Science.gov (United States)

Byun, Tae-Young

This paper presents a prototype of inter-vehicle communication system using mobile access point that internetworks wired or wireless LAN and wireless WAN anywhere. Implemented mobile access point can be equipped with various wireless WAN interfaces such as WCDMA and HSDPA. Mobile access point in the IP mechanism has to process connection setup procedure to one wireless WAN. To show the applicability of the mobile access point to inter-vehicle communication, a simplified V2I2V-based car communication system called ICSW2AN is implemented to evaluate major performance metrics by road test. In addition, results of road test for traffic information service are investigated in view of RTT, latency and server processing time. The experimental result indicates that V2I2V-based car communication system sufficiently can provide time-tolerant traffic information to moving vehicles while more than two mobile devices in restricted spaces such as car, train and ship access wireless Internet simultaneously.

Demystifying Open Access

International Nuclear Information System (INIS)

Mele, Salvatore

2007-01-01

The tenets of Open Access are to grant anyone, anywhere and anytime free access to the results of scientific research. HEP spearheaded the Open Access dissemination of scientific results with the mass mailing of preprints in the pre-WWW era and with the launch of the arXiv preprint system at the dawn of the '90s. The HEP community is now ready for a further push to Open Access while retaining all the advantages of the peer-review system and, at the same time, bring the spiralling cost of journal subscriptions under control. I will present a possible plan for the conversion to Open Access of HEP peer-reviewed journals, through a consortium of HEP funding agencies, laboratories and libraries: SCOAP3 (Sponsoring Consortium for Open Access Publishing in Particle Physics). SCOAP3 will engage with scientific publishers towards building a sustainable model for Open Access publishing, which is as transparent as possible for HEP authors. The current system in which journals income comes from subscription fees is replaced with a scheme where SCOAP3 compensates publishers for the costs incurred to organise the peer-review service and give Open Access to the final version of articles. SCOAP3 will be funded by all countries active in HEP under a 'fair share' scenario, according to their production of HEP articles. In this talk I will present a short overview of the history of Open Access in HEP, the details of the SCOAP3 model and the outlook for its implementation.

Predictors of appendiceal perforation in an equal access system.

Science.gov (United States)

Walker, Avery; Hatch, Quinton; Drake, Thurston; Nelson, Daniel W; Fitzpatrick, Emilie; Bingham, Jason; Black, George; Maykel, Justin A; Steele, Scott R

2014-07-01

Discrepancies in socioeconomic factors have been associated with higher rates of perforated appendicitis. As an equal-access health care system theoretically removes these barriers, we aimed to determine if remaining differences in demographics, education, and pay result in disparate outcomes in the rate of perforated appendicitis. All patients undergoing appendectomy for acute appendicitis (November 2004-October 2009) at a tertiary care equal access institution were categorized by demographics and perioperative data. Rank of the sponsor was used as a surrogate for economic status. A multivariate logistic regression model was performed to determine patient and clinical characteristics associated with perforated appendicitis. A total of 680 patients (mean age 30±16 y; 37% female) were included. The majority were Caucasian (56.4% [n=384]; African Americans 5.6% [n=38]; Asians 1.9% [n=13]; and other 48.9% [n=245]) and enlisted (87.2%). Overall, 6.4% presented with perforation, with rates of 6.6%, 5.8%, and 6.7% (P=0.96) for officers, enlisted soldiers, and contractors, respectively. There was no difference in perforation when stratified by junior or senior status for either officers or enlisted (9.3% junior versus 4.40% senior officers, P=0.273; 6.60% junior versus 5.50% senior enlisted, P=0.369). On multivariate analysis, parameters such as leukocytosis and temperature, as well as race and rank were not associated with perforation (P=0.7). Only age had a correlation, with individuals aged 66-75 y having higher perforation rates (odds ratio, 1.04; 95% confidence interval, 1.02-1.05; P<0.001). In an equal-access health care system, older age, not socioeconomic factors, correlated with increased appendiceal perforation rates. Published by Elsevier Inc.

“Future Directions”: m-government computer systems accessed via cloud computing – advantages and possible implementations

OpenAIRE

Daniela LIŢAN

2015-01-01

In recent years, the activities of companies and Public Administration had been automated and adapted to the current information system. Therefore, in this paper, I will present and exemplify the benefits of m-government computer systems development and implementation (which can be accessed from mobile devices and which are specific to the workflow of Public Administrations) starting from the “experience” of e-government systems implementation in the context of their access and usage through ...

Access systems strategy in the accelerator complex and experimental areas

International Nuclear Information System (INIS)

Nunes, R.; Ninin, P.; Sanchez-Corral, E.; Ladzinski, T.

2012-01-01

This paper reviews the main features of the new PS Personnel Protection System (PSPSS) as well as the main milestones for its deployment during the Long Shutdown of 2013-2014. Access conditions in the PS, SPS and LHC complexes during this period shall be described as well as the upgrades and improvements that are under preparation. (authors)

Defense Hotline Allegations Concerning the Biometric Identification System for Access Omnibus Contract

National Research Council Canada - National Science Library

2008-01-01

.... According to the Strategic Services Sourcing (S3) performance work statement the purpose of the BISA is to provide a biometric base access control system that can operate in a hostile environment...

Guide on Project Web Access of SFR R and D and Technology Monitoring System

International Nuclear Information System (INIS)

Lee, Dong Uk; Won, Byung Chool; Lee, Yong Bum; Kim, Young In; Hahn, Do Hee

2008-09-01

The SFR R and D and technology monitoring system based on the MS enterprise project management is developed for systematic effective management of 'Development of Basic Key Technologies for Gen IV SFR' project which was performed under the Mid- and Long-term Nuclear R and D Program sponsored by the Ministry of Education, Science and Technology. This system is a tool for project management based on web access. Therefore this manual is a detailed guide for Project Web Access(PWA). Section 1 describes the common guide for using of system functions such as project server 2007 client connection setting, additional outlook function setting etc. The section 2 describes the guide for system administrator. It is described the guide for project management in section 3, 4

Performance enhancement of optical code-division multiple-access systems using transposed modified Walsh code

Science.gov (United States)

Sikder, Somali; Ghosh, Shila

2018-02-01

This paper presents the construction of unipolar transposed modified Walsh code (TMWC) and analysis of its performance in optical code-division multiple-access (OCDMA) systems. Specifically, the signal-to-noise ratio, bit error rate (BER), cardinality, and spectral efficiency were investigated. The theoretical analysis demonstrated that the wavelength-hopping time-spreading system using TMWC was robust against multiple-access interference and more spectrally efficient than systems using other existing OCDMA codes. In particular, the spectral efficiency was calculated to be 1.0370 when TMWC of weight 3 was employed. The BER and eye pattern for the designed TMWC were also successfully obtained using OptiSystem simulation software. The results indicate that the proposed code design is promising for enhancing network capacity.

Guide on Project Web Access of SFR R and D and Technology Monitoring System

Energy Technology Data Exchange (ETDEWEB)

Lee, Dong Uk; Won, Byung Chool; Lee, Yong Bum; Kim, Young In; Hahn, Do Hee

2008-09-15

The SFR R and D and technology monitoring system based on the MS enterprise project management is developed for systematic effective management of 'Development of Basic Key Technologies for Gen IV SFR' project which was performed under the Mid- and Long-term Nuclear R and D Program sponsored by the Ministry of Education, Science and Technology. This system is a tool for project management based on web access. Therefore this manual is a detailed guide for Project Web Access(PWA). Section 1 describes the common guide for using of system functions such as project server 2007 client connection setting, additional outlook function setting etc. The section 2 describes the guide for system administrator. It is described the guide for project management in section 3, 4.

Scheduling with Bus Access Optimization for Distributed Embedded Systems

DEFF Research Database (Denmark)

Eles, Petru; Doboli, Alex; Pop, Paul

2000-01-01

of control. Our goal is to derive a worst case delay by which the system completes execution, such that this delay is as small as possible; to generate a logically and temporally deterministic schedule; and to optimize parameters of the communication protocol such that this delay is guaranteed. We have......In this paper, we concentrate on aspects related to the synthesis of distributed embedded systems consisting of programmable processors and application-specific hardware components. The approach is based on an abstract graph representation that captures, at process level, both dataflow and the flow......, generates an efficient bus access scheme as well as the schedule tables for activation of processes and communications....

Introduction to the Personal Access Satellite System Study

Science.gov (United States)

Sue, Miles K.

1990-01-01

A recent study by the National Telecommunications and Information Administration (NTIA) has concluded that the 21st century will be the age of information in which the telecommunication infrastructure will be vital to the social and economic well being of society. To meet the challenge of the coming age, JPL has been performing studies on a personal access satellite system (PASS) for the 21st century. The PASS study can be traced back to a study in which the technical feasibility and potential applications of a high frequency, low data rate satellite system were identified using small fixed terminals. Herein, the PASS concept is described along with the strawman design. Then the key challenges are identified along with possible solutions. Finally, the plan for the future is summarized from the key results.

Development of Remote Monitoring and a Control System Based on PLC and WebAccess for Learning Mechatronics

Directory of Open Access Journals (Sweden)

Wen-Jye Shyr

2013-02-01

Full Text Available This study develops a novel method for learning mechatronics using remote monitoring and control, based on a programmable logic controller (PLC and WebAccess. A mechatronics module, a Web-CAM and a PLC were integrated with WebAccess software to organize a remote laboratory. The proposed system enables users to access the Internet for remote monitoring and control of the mechatronics module via a web browser, thereby enhancing work flexibility by enabling personnel to control mechatronics equipment from a remote location. Mechatronics control and long-distance monitoring were realized by establishing communication between the PLC and WebAccess. Analytical results indicate that the proposed system is feasible. The suitability of this system is demonstrated in the department of industrial education and technology at National Changhua University of Education, Taiwan. Preliminary evaluation of the system was encouraging and has shown that it has achieved success in helping students understand concepts and master remote monitoring and control techniques.

Welcome to Systems — A New Interdisciplinary Open Access Journal for Systems Science and Engineering

Directory of Open Access Journals (Sweden)

Thomas Huynh

2012-04-01

Full Text Available Natural and human-made systems abound around us. Our solar system, the human body, the food chain, and ecosystems are some examples of natural systems. Some human-made systems are transportation systems, weapon systems, computer systems, software systems, satellite communications systems, ships, missile defense systems, health care systems, the internet, financial systems, and regional economies. Understanding of natural systems is essential to the survival of the human species, which is intertwined with the survival of other species on earth. Having the knowledge and ability to build human-made systems is critical to the employment of systems that effectively serve the needs of their users. To gain such understanding and to acquire such knowledge and ability, it is necessary that cutting-edge research in systems science, systems engineering, and systems-related fields continue. This open access journal aims to achieve quick and global dissemination of results of such research. [...

Development of Decision-Making Automated System for Optimal Placement of Physical Access Control System’s Elements

Science.gov (United States)

Danilova, Olga; Semenova, Zinaida

2018-04-01

The objective of this study is a detailed analysis of physical protection systems development for information resources. The optimization theory and decision-making mathematical apparatus is used to formulate correctly and create an algorithm of selection procedure for security systems optimal configuration considering the location of the secured object’s access point and zones. The result of this study is a software implementation scheme of decision-making system for optimal placement of the physical access control system’s elements.

Risk of infection due to medical interventions via central venous catheters or implantable venous access port systems at the middle port of a three-way cock: luer lock cap vs. luer access split septum system (Q-Syte).

Science.gov (United States)

Pohl, Fabian; Hartmann, Werner; Holzmann, Thomas; Gensicke, Sandra; Kölbl, Oliver; Hautmann, Matthias G

2014-01-25

Many cancer patients receive a central venous catheter or port system prior to therapy to assure correct drug administration. Even appropriate hygienic intervention maintenance carries the risk of contaminating the middle port (C-port) of a three-way cock (TWC), a risk that increases with the number of medical interventions. Because of the complexity of the cleaning procedure with disconnection and reconnection of the standard luer lock cap (referred as "intervention"), we compared luer lock caps with a "closed access system" consisting of a luer access split septum system with regard to process optimization (work simplification, process time), efficiency (costs) and hygiene (patient safety). For determination of process optimization the workflow of an intervention according to the usual practice and risks was depicted in a process diagram. For determining the actual process costs, we analyzed use of material and time parameters per intervention and used the process parameters for programming the process into a simulation run (n = 1000) to determine the process costs as well as their differences (ACTUAL vs. NOMINAL) within the framework of a discrete event simulation.Additionally cultures were carried out at the TWC C-ports to evaluate possible contamination. With the closed access system, the mean working time of 5.5 minutes could be reduced to 2.97 minutes. The results for average process costs (labour and material costs per use) were 3.92 € for luer lock caps and 2.55 € for the closed access system. The hypothesis test (2-sample t-test, CI 0.95, p-valuerisks (related to material, surroundings, staff handling) could be reduced by 65.38%. In the present research, the closed access system with a divided split septum was superior to conventional luer lock caps. The advantage of the closed access system lies in the simplified handling for staff, which results in a reduced risk of patient infection due to improved clinical hygiene.

Study and development of a document file system with selective access

International Nuclear Information System (INIS)

Mathieu, Jean-Claude

1974-01-01

The objective of this research thesis was to design and to develop a set of software aimed at an efficient management of a document file system by using methods of selective access to information. Thus, the three main aspects of file processing (creation, modification, reorganisation) have been addressed. The author first presents the main problems related to the development of a comprehensive automatic documentation system, and their conventional solutions. Some future aspects, notably dealing with the development of peripheral computer technology, are also evoked. He presents the characteristics of INIS bibliographic records provided by the IAEA which have been used to create the files. In the second part, he briefly describes the file system general organisation. This system is based on the use of two main files: an inverse file which contains for each descriptor a list of of numbers of files indexed by this descriptor, and a dictionary of descriptor or input file which gives access to the inverse file. The organisation of these both files is then describes in a detailed way. Other related or associated files are created, and the overall architecture and mechanisms integrated into the file data input software are described, as well as various processing applied to these different files. Performance and possible development are finally discussed

U-Access: a web-based system for routing pedestrians of differing abilities

Science.gov (United States)

Sobek, Adam D.; Miller, Harvey J.

2006-09-01

For most people, traveling through urban and built environments is straightforward. However, for people with physical disabilities, even a short trip can be difficult and perhaps impossible. This paper provides the design and implementation of a web-based system for the routing and prescriptive analysis of pedestrians with different physical abilities within built environments. U-Access, as a routing tool, provides pedestrians with the shortest feasible route with respect to one of three differing ability levels, namely, peripatetic (unaided mobility), aided mobility (mobility with the help of a cane, walker or crutches) and wheelchair users. U-Access is also an analytical tool that can help identify obstacles in built environments that create routing discrepancies among pedestrians with different physical abilities. This paper discusses the system design, including database, algorithm and interface specifications, and technologies for efficiently delivering results through the World Wide Web (WWW). This paper also provides an illustrative example of a routing problem and an analytical evaluation of the existing infrastructure which identifies the obstacles that pose the greatest discrepancies between physical ability levels. U-Access was evaluated by wheelchair users and route experts from the Center for Disability Services at The University of Utah, USA.

The equipment access software for a distributed UNIX-based accelerator control system

International Nuclear Information System (INIS)

Trofimov, Nikolai; Zelepoukine, Serguei; Zharkov, Eugeny; Charrue, Pierre; Gareyte, Claire; Poirier, Herve

1994-01-01

This paper presents a generic equipment access software package for a distributed control system using computers with UNIX or UNIX-like operating systems. The package consists of three main components, an application Equipment Access Library, Message Handler and Equipment Data Base. An application task, which may run in any computer in the network, sends requests to access equipment through Equipment Library calls. The basic request is in the form Equipment-Action-Data and is routed via a remote procedure call to the computer to which the given equipment is connected. In this computer the request is received by the Message Handler. According to the type of the equipment connection, the Message Handler either passes the request to the specific process software in the same computer or forwards it to a lower level network of equipment controllers using MIL1553B, GPIB, RS232 or BITBUS communication. The answer is then returned to the calling application. Descriptive information required for request routing and processing is stored in the real-time Equipment Data Base. The package has been written to be portable and is currently available on DEC Ultrix, LynxOS, HPUX, XENIX, OS-9 and Apollo domain. ((orig.))

An API-based search system for one click access to information

NARCIS (Netherlands)

Ionita, Dan; Tax, Niek; Hiemstra, Djoerd

This paper proposes a prototype One Click access system, based on previous work in the field and the related 1CLICK-2@NTCIR10 task. The proposed solution integrates methods from into a three tier algorithm: query categorization, information extraction and output generation and offers suggestions on

Completeness and overlap in open access systems: Search engines, aggregate institutional repositories and physics-related open sources.

Science.gov (United States)

Tsay, Ming-Yueh; Wu, Tai-Luan; Tseng, Ling-Li

2017-01-01

This study examines the completeness and overlap of coverage in physics of six open access scholarly communication systems, including two search engines (Google Scholar and Microsoft Academic), two aggregate institutional repositories (OAIster and OpenDOAR), and two physics-related open sources (arXiv.org and Astrophysics Data System). The 2001-2013 Nobel Laureates in Physics served as the sample. Bibliographic records of their publications were retrieved and downloaded from each system, and a computer program was developed to perform the analytical tasks of sorting, comparison, elimination, aggregation and statistical calculations. Quantitative analyses and cross-referencing were performed to determine the completeness and overlap of the system coverage of the six open access systems. The results may enable scholars to select an appropriate open access system as an efficient scholarly communication channel, and academic institutions may build institutional repositories or independently create citation index systems in the future. Suggestions on indicators and tools for academic assessment are presented based on the comprehensiveness assessment of each system.

Android Access Control Extension

Directory of Open Access Journals (Sweden)

Anton Baláž

2015-12-01

Full Text Available The main objective of this work is to analyze and extend security model of mobile devices running on Android OS. Provided security extension is a Linux kernel security module that allows the system administrator to restrict program's capabilities with per-program profiles. Profiles can allow capabilities like network access, raw socket access, and the permission to read, write, or execute files on matching paths. Module supplements the traditional Android capability access control model by providing mandatory access control (MAC based on path. This extension increases security of access to system objects in a device and allows creating security sandboxes per application.

5 CFR 293.504 - Composition of, and access to, the Employee Medical File System.

Science.gov (United States)

2010-01-01

... Employee Medical File System. 293.504 Section 293.504 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PERSONNEL RECORDS Employee Medical File System Records § 293.504 Composition of, and access to, the Employee Medical File System. (a) All employee occupational medical records...

Experimental demonstration of 2.5 Gbit/S incoherent two-dimensional optical code division multiple access system

International Nuclear Information System (INIS)

Glesk, I.; Baby, V.; Bres, C.-S.; Xu, L.; Rand, D.; Prucnal, P.R.

2004-01-01

We demonstrated error-free operation of 4 simultaneous users in a fast frequency-hopping time-spreading optical code division multiple access system operating at 2.5 Gbit/s a Star architecture. Effective power penalty was ≤0.5dB. Novel optical code division multiple access receiver based on Terahertz Optical Asymmetric Demultiplexer was demonstrated to eliminate multiple access interference (Authors)

High security chaotic multiple access scheme for visible light communication systems with advanced encryption standard interleaving

Science.gov (United States)

Qiu, Junchao; Zhang, Lin; Li, Diyang; Liu, Xingcheng

2016-06-01

Chaotic sequences can be applied to realize multiple user access and improve the system security for a visible light communication (VLC) system. However, since the map patterns of chaotic sequences are usually well known, eavesdroppers can possibly derive the key parameters of chaotic sequences and subsequently retrieve the information. We design an advanced encryption standard (AES) interleaving aided multiple user access scheme to enhance the security of a chaotic code division multiple access-based visible light communication (C-CDMA-VLC) system. We propose to spread the information with chaotic sequences, and then the spread information is interleaved by an AES algorithm and transmitted over VLC channels. Since the computation complexity of performing inverse operations to deinterleave the information is high, the eavesdroppers in a high speed VLC system cannot retrieve the information in real time; thus, the system security will be enhanced. Moreover, we build a mathematical model for the AES-aided VLC system and derive the theoretical information leakage to analyze the system security. The simulations are performed over VLC channels, and the results demonstrate the effectiveness and high security of our presented AES interleaving aided chaotic CDMA-VLC system.

Computer network access to scientific information systems for minority universities

Science.gov (United States)

Thomas, Valerie L.; Wakim, Nagi T.

1993-08-01

The evolution of computer networking technology has lead to the establishment of a massive networking infrastructure which interconnects various types of computing resources at many government, academic, and corporate institutions. A large segment of this infrastructure has been developed to facilitate information exchange and resource sharing within the scientific community. The National Aeronautics and Space Administration (NASA) supports both the development and the application of computer networks which provide its community with access to many valuable multi-disciplinary scientific information systems and on-line databases. Recognizing the need to extend the benefits of this advanced networking technology to the under-represented community, the National Space Science Data Center (NSSDC) in the Space Data and Computing Division at the Goddard Space Flight Center has developed the Minority University-Space Interdisciplinary Network (MU-SPIN) Program: a major networking and education initiative for Historically Black Colleges and Universities (HBCUs) and Minority Universities (MUs). In this paper, we will briefly explain the various components of the MU-SPIN Program while highlighting how, by providing access to scientific information systems and on-line data, it promotes a higher level of collaboration among faculty and students and NASA scientists.

The Baker system for nuclear access authorization screening: a psychologically developed system for access screening of vendor and owner applicants at nuclear power plants

International Nuclear Information System (INIS)

Baker, E.G.; Crouter, F.L.

1985-01-01

This paper presents a comprehensive screening program for unescorted access which has proven to be highly effective in determining the intergrity, trustworthiness, socialibility, behaviors and tendencies of an employee applicant--past, present and future. This procedure, designed specifically for the nuclear industry, can be used with owner or vendor applicants, and meets or exceeds all of the NRC's requirements. The Baker system has been used for nuclear selection since 1979

A fuzzy expert system to Trust-Based Access Control in crowdsourcing environments

Directory of Open Access Journals (Sweden)

Olusegun Folorunso

2015-07-01

Full Text Available Crowdsourcing has been widely accepted across a broad range of application areas. In crowdsourcing environments, the possibility of performing human computation is characterized with risks due to the openness of their web-based platforms where each crowd worker joins and participates in the process at any time, causing serious effect on the quality of its computation. In this paper, a combination of Trust-Based Access Control (TBAC strategy and fuzzy-expert systems was used to enhance the quality of human computation in crowdsourcing environment. A TBAC-fuzzy algorithm was developed and implemented using MATLAB 7.6.0 to compute trust value (Tvalue, priority value as evaluated by fuzzy inference system (FIS and finally generate access decision to each crowd-worker. In conclusion, the use of TBAC is feasible in improving quality of human computation in crowdsourcing environments.

Effects of Job Accessibility Improved by Public Transport System: Natural Experimental Evidence from the Copenhagen Metro

DEFF Research Database (Denmark)

Pons Rotger, Gabriel Angel; Nielsen, Thomas Alexander Sick

2015-01-01

This study examines the effect of accessibility to urban jobs via a public transport system on individual earnings and commuting behaviour. The effect of improved public transport based accessibility on these outcomes is determined by exploiting the exogenous variation in access to a public rail ...... with a change in commuting patterns as the improved access to public transport facilitates a shift from employment within the township to better paid jobs in the city centre, as well as in other suburbs of the Copenhagen Metropolitan area...

Accés per Multiplexació de Freqüències Ortogonals per Xarxes Òptiques Passives: una aproximació práctica

OpenAIRE

Peralta Gallardo, Ángel

2012-01-01

OFDMA applied for future optical networks [ANGLÈS] Research activities for new alternatives in ultra fast transmission over optical fiber networks are looking towards Orthogonal Frequency Division Multiplexing (OFDM) which is used in different modern communication systems such as LTE, WiFi or WiMax because of the following reasons: tolerance to channel limitations, better spectral exploitation, scalability, flexibility and implementation feasibility with state of the art electronics. These...

Above the nominal limit performance evaluation of multiwavelength optical code-division multiple-access systems

Science.gov (United States)

Inaty, Elie; Raad, Robert; Fortier, Paul; Shalaby, Hossam M. H.

2009-03-01

We provide an analysis for the performance of a multiwavelength optical code-division multiple-access (MW-OCDMA) network when the system is working above the nominal transmission rate limit imposed by passive encoding-decoding operation. We address the problem of overlapping in such a system and how it can directly affect the bit error rate (BER). A unified mathematical framework is presented under the assumption of one-coincidence sequences with nonrepeating wavelengths. A closed form expression of the multiple access interference limited BER is provided as a function of different system parameters. Results show that the performance of the MW-OCDMA system can be critically affected when working above the nominal limit, an event that can happen when the network operates at a high transmission rate. In addition, the impact of the derived error probability on the performance of two newly proposed medium access control (MAC) protocols, the S-ALOHA and the R3T, is also investigated. It is shown that for low transmission rates, the S-ALOHA is better than the R3T, while the R3T is better at very high transmission rates. In general, it is postulated that the R3T protocol suffers a higher delay mainly because of the presence of additional modes.

Completeness and overlap in open access systems: Search engines, aggregate institutional repositories and physics-related open sources.

Directory of Open Access Journals (Sweden)

Ming-Yueh Tsay

Full Text Available This study examines the completeness and overlap of coverage in physics of six open access scholarly communication systems, including two search engines (Google Scholar and Microsoft Academic, two aggregate institutional repositories (OAIster and OpenDOAR, and two physics-related open sources (arXiv.org and Astrophysics Data System. The 2001-2013 Nobel Laureates in Physics served as the sample. Bibliographic records of their publications were retrieved and downloaded from each system, and a computer program was developed to perform the analytical tasks of sorting, comparison, elimination, aggregation and statistical calculations. Quantitative analyses and cross-referencing were performed to determine the completeness and overlap of the system coverage of the six open access systems. The results may enable scholars to select an appropriate open access system as an efficient scholarly communication channel, and academic institutions may build institutional repositories or independently create citation index systems in the future. Suggestions on indicators and tools for academic assessment are presented based on the comprehensiveness assessment of each system.

Massive M2M Access with Reliability Guarantees in LTE Systems

DEFF Research Database (Denmark)

Madueño, Germán Corrales; Kiilerich Pratas, Nuno; Stefanovic, Cedomir

2015-01-01

Machine-to-Machine (M2M) communications are one of the major drivers of the cellular network evolution towards 5G systems. One of the key challenges is on how to provide reliability guarantees to each accessing device in a situation in which there is a massive number of almost-simultaneous arriva...

A service-oriented data access control model

Science.gov (United States)

Meng, Wei; Li, Fengmin; Pan, Juchen; Song, Song; Bian, Jiali

2017-01-01

The development of mobile computing, cloud computing and distributed computing meets the growing individual service needs. Facing with complex application system, it's an urgent problem to ensure real-time, dynamic, and fine-grained data access control. By analyzing common data access control models, on the basis of mandatory access control model, the paper proposes a service-oriented access control model. By regarding system services as subject and data of databases as object, the model defines access levels and access identification of subject and object, and ensures system services securely to access databases.

Flexible CP-ABE Based Access Control on Encrypted Data for Mobile Users in Hybrid Cloud System

Institute of Scientific and Technical Information of China (English)

Wen-Min Li; Xue-Lei Li; Qiao-Yan Wen; Shuo Zhang; Hua Zhang

2017-01-01

In hybrid cloud computing, encrypted data access control can provide a fine-grained access method for orga-nizations to enact policies closer to organizational policies. This paper presents an improved CP-ABE (ciphertext-policy attribute-based encryption) scheme to construct an encrypted data access control solution that is suitable for mobile users in hybrid cloud system. In our improvement, we split the original decryption keys into a control key, a secret key and a set of transformation keys. The private cloud managed by the organization administrator takes charge of updating the transformation keys using the control key. It helps to handle the situation of flexible access management and attribute alteration. Meanwhile, the mobile user's single secret key remains unchanged as well as the ciphertext even if the data user's attribute has been revoked. In addition, we modify the access control list through adding the attributes with corresponding control key and transformation keys so as to manage user privileges depending upon the system version. Finally, the analysis shows that our scheme is secure, flexible and efficient to be applied in mobile hybrid cloud computing.

Multi-views storage model and access methods of conversation history in converged IP messaging system

Science.gov (United States)

Lu, Meilian; Yang, Dong; Zhou, Xing

2013-03-01

Based on the analysis of the requirements of conversation history storage in CPM (Converged IP Messaging) system, a Multi-views storage model and access methods of conversation history are proposed. The storage model separates logical views from physical storage and divides the storage into system managed region and user managed region. It simultaneously supports conversation view, system pre-defined view and user-defined view of storage. The rationality and feasibility of multi-view presentation, the physical storage model and access methods are validated through the implemented prototype. It proves that, this proposal has good scalability, which will help to optimize the physical data storage structure and improve storage performance.

Open Access Intellectual Property Systems: A Comparison to Commercial Solutions in Competitive Intelligence

Directory of Open Access Journals (Sweden)

Jan Cerny

2016-07-01

Full Text Available ICT/IS management plays an important role within the framework of innovation management, and one of the key elements of this role is the support of Competitive Intelligence in the context of innovation processes. The strategic information needs of innovation management are also directed towards different kinds of intellectual property (IP information entities and commercialization. The purpose of this paper is to define these entities and IP information systems as an important part of a company’s Competitive Intelligence Unit for competitor analysis and technology trends. The open access IP information systems will be analysed together with commercial solutions.. The aim of this paper is to underline the importance of open access IP systems compared to added value commercial solutions for competitive intelligence purposes for SMEs. The comparison will be carried out using examples of patent searches within a concrete dataset.

Multi-level access control in the data pipeline of the international supply chain system

NARCIS (Netherlands)

Pruksasri, P.; Berg, J. van den; Hofman, W.; Daskapan, S.

2013-01-01

The Seamless Integrated Data Pipeline system was proposed to the European Union in order to overcome the information quality shortcomings of the current international supply chain information exchange systems. Next to identification and authorization of stakeholders, secure access control needs to

National Geothermal Data System (USA): an Exemplar of Open Access to Data

Science.gov (United States)

Allison, M. Lee; Richard, Stephen; Blackman, Harold; Anderson, Arlene; Patten, Kim

2014-05-01

The National Geothermal Data System's (NGDS - www.geothermaldata.org) formal launch in April, 2014 will provide open access to millions of data records, sharing -relevant geoscience and longer term to land use data to propel geothermal development and production. NGDS serves information from all of the U.S. Department of Energy's sponsored development and research projects and geologic data from all 50 states, using free and open source software. This interactive online system is opening new exploration opportunities and potentially shortening project development by making data easily discoverable, accessible, and interoperable. We continue to populate our prototype functional data system with multiple data nodes and nationwide data online and available to the public. Data from state geological surveys and partners includes more than 6 million records online, including 1.72 million well headers (oil and gas, water, geothermal), 670,000 well logs, and 497,000 borehole temperatures and is growing rapidly. There are over 312 interoperable Web services and another 106 WMS (Web Map Services) registered in the system as of January, 2014. Companion projects run by Southern Methodist University and U.S. Geological Survey (USGS) are adding millions of additional data records. The DOE Geothermal Data Repository, currently hosted on OpenEI, is a system node and clearinghouse for data from hundreds of U.S. DOE-funded geothermal projects. NGDS is built on the US Geoscience Information Network (USGIN) data integration framework, which is a joint undertaking of the USGS and the Association of American State Geologists (AASG). NGDS complies with the White House Executive Order of May 2013, requiring all federal agencies to make their data holdings publicly accessible online in open source, interoperable formats with common core and extensible metadata. The National Geothermal Data System is being designed, built, deployed, and populated primarily with support from the US

Reduction of the near-far effect in mobile communication systems with Code-Division Multiple-Access

Science.gov (United States)

Purchla, Magdalena

2006-02-01

In this paper the basic methods for reducing Multiple Access Interference (MAI) and combating the near-far effect in Direct-Sequence Code-Division Multiple-Access (DS-CDMA) mobile communication systems are presented. MAI and the near-far effect are inevitable in DS-CDMA systems with quasi-orthogonal spreading sequences. An effective method of reducing MAI can increase the capacity of the system that is why so many researchers are working in this field. In this article three most important techniques of decreasing MAI are presented: power control, multiuser detection and space-time processing. There is a short introduction to each topic and one or more examples found in literature of algorithms suitable for practical applications (although not all algorithms are yet used in existing systems).

Providing Internet Access to the Ohio Career Information System for All Residents: A Feasibility Study.

Science.gov (United States)

Lewis, Morgan V.

Expanded Internet access to the Ohio Career Information System (OCIS) would provide adults in Ohio who need to or wish to make career changes with the best available information about occupations, education and training programs, and financial aid. In order to determine the feasibility of improving access without cost to users, an advisory group,…

Synergies in the Asian energy system: Climate change, energy security, energy access and air pollution

International Nuclear Information System (INIS)

Vliet, Oscar van; Krey, Volker; McCollum, David; Pachauri, Shonali; Nagai, Yu; Rao, Shilpa; Riahi, Keywan

2012-01-01

We use the MESSAGE model to examine multiple dimensions of sustainable development for three Asian regions in a set of scenarios developed for the Asian Modelling Exercise. Using climate change mitigation as a starting point for the analysis, we focus on the interaction of climate and energy with technology choice, energy security, energy access, and air pollution, which often have higher policy priority than climate change. Stringent climate policies drive the future energy supply in Asia from being dominated by coal and oil to a more diversified system based mostly on natural gas, coal with CCS, nuclear and renewable energy. The increase in diversity helps to improve the energy security of individual countries and regions. Combining air pollution control policies and universal energy access policies with climate policy can further help to reduce both outdoor and indoor air pollution related health impacts. Investments into the energy system must double by 2030 to achieve stringent climate goals, but are largely offset by lower costs for O and M and air pollution abatement. Strong focus on end-use efficiency also helps lowering overall total costs and allows for limiting or excluding supply side technologies from the mitigation portfolio. Costs of additional energy access policies and measures are a small fraction of total energy system costs. - Highlights: ► Half of added investments in energy offset by lower costs for O and M and air pollution. ► Costs for achieving universal energy access much smaller than energy system costs. ► Combined emissions and access policies further reduce air pollution impacts on health. ► Strong focus on end-use efficiency allows for more flexibility on energy sources. ► Stringent climate policy can improve energy security of Asian regions.

75 FR 4101 - Enterprise Income Verification (EIV) System User Access Authorization Form and Rules of Behavior...

Science.gov (United States)

2010-01-26

... DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT [Docket No. FR-5376-N-05] Enterprise Income Verification (EIV) System User Access Authorization Form and Rules of Behavior and User Agreement AGENCY... Access, Authorization Form and Rules Of Behavior and User Agreement. OMB Approval Number: 2577-New. Form...

Design and Implementation of a Web-based Monitoring System by using EPICS Channel Access Protocol

International Nuclear Information System (INIS)

An, Eun Mi; Song, Yong Gi

2009-01-01

Proton Engineering Frontier Project (PEFP) has developed a 20MeV proton accelerator, and established a distributed control system based on EPICS for sub-system components such as vacuum unit, beam diagnostics, and power supply system. The control system includes a real-time monitoring and alarm functions. From the aspect of a efficient maintenance of a control system and a additional extension of subsystems, EPICS software framework was adopted. In addition, a control system should be capable of providing an easy access for users and a real-time monitoring on a user screen. Therefore, we have implemented a new web-based monitoring server with several libraries. By adding DB module, the new IOC web monitoring system makes it possible to monitor the system through the web. By integrating EPICS Channel Access (CA) and Database libraries into a Database module, the web-based monitoring system makes it possible to monitor the sub-system status through user's internet browser. In this study, we developed a web based monitoring system by using EPICS IOC (Input Output Controller) with IBM server

Return Migrants’ Experience of Access to Care in Corrupt Healthcare Systems: The Bosnian Example

Directory of Open Access Journals (Sweden)

Line Neerup Handlos

2016-09-01

Full Text Available Equal and universal access to healthcare services is a core priority for a just health system. A key societal determinant seen to create inequality in access to healthcare is corruption in the healthcare system. How return migrants’ access to healthcare is affected by corruption is largely unstudied, even though return migrants may be particularly vulnerable to problems related to corruption due to their period of absence from their country of origin. This article investigates how corruption in the healthcare sector affects access to healthcare for refugees who repatriated to Bosnia, a country with a high level of corruption, from Denmark, a country with a low level of corruption. The study is based on 18 semi-structured interviews with 33 refugees who returned after long-term residence in Denmark. We found that the returned refugees faced greater problems with corruption than was the case for those who had not left the country, as doctors considered them to be better endowed financially and therefore demanded larger bribes from them than they did from those who had remained in Bosnia. Moreover, during their stay abroad the returnees had lost the connections that could have helped them sidestep the corruption. Returned refugees are thus particularly vulnerable to the effects of corruption.

Return Migrants’ Experience of Access to Care in Corrupt Healthcare Systems: The Bosnian Example

Science.gov (United States)

Neerup Handlos, Line; Fog Olwig, Karen; Bygbjerg, Ib Christian; Norredam, Marie

2016-01-01

Equal and universal access to healthcare services is a core priority for a just health system. A key societal determinant seen to create inequality in access to healthcare is corruption in the healthcare system. How return migrants’ access to healthcare is affected by corruption is largely unstudied, even though return migrants may be particularly vulnerable to problems related to corruption due to their period of absence from their country of origin. This article investigates how corruption in the healthcare sector affects access to healthcare for refugees who repatriated to Bosnia, a country with a high level of corruption, from Denmark, a country with a low level of corruption. The study is based on 18 semi-structured interviews with 33 refugees who returned after long-term residence in Denmark. We found that the returned refugees faced greater problems with corruption than was the case for those who had not left the country, as doctors considered them to be better endowed financially and therefore demanded larger bribes from them than they did from those who had remained in Bosnia. Moreover, during their stay abroad the returnees had lost the connections that could have helped them sidestep the corruption. Returned refugees are thus particularly vulnerable to the effects of corruption. PMID:27657096

Return Migrants' Experience of Access to Care in Corrupt Healthcare Systems: The Bosnian Example.

Science.gov (United States)

Neerup Handlos, Line; Fog Olwig, Karen; Bygbjerg, Ib Christian; Norredam, Marie

2016-09-19

Equal and universal access to healthcare services is a core priority for a just health system. A key societal determinant seen to create inequality in access to healthcare is corruption in the healthcare system. How return migrants' access to healthcare is affected by corruption is largely unstudied, even though return migrants may be particularly vulnerable to problems related to corruption due to their period of absence from their country of origin. This article investigates how corruption in the healthcare sector affects access to healthcare for refugees who repatriated to Bosnia, a country with a high level of corruption, from Denmark, a country with a low level of corruption. The study is based on 18 semi-structured interviews with 33 refugees who returned after long-term residence in Denmark. We found that the returned refugees faced greater problems with corruption than was the case for those who had not left the country, as doctors considered them to be better endowed financially and therefore demanded larger bribes from them than they did from those who had remained in Bosnia. Moreover, during their stay abroad the returnees had lost the connections that could have helped them sidestep the corruption. Returned refugees are thus particularly vulnerable to the effects of corruption.

Multigigabit W-Band (75–110 GHz) Bidirectional Hybrid Fiber-Wireless Systems in Access Networks

DEFF Research Database (Denmark)

Pang, Xiaodan; Lebedev, Alexander; Vegas Olmos, Juan José

2014-01-01

compare the transmission performances in terms of achievable wireless distances with and without using a high-frequency electrical power amplifier at the wireless transmitter. A downlink 16-Gbit/s QPSK signal and an uplink 1.25-Gbit/s ASK signal transmission over the two implementations are experimentally......We experimentally demonstrate multigigabit capacity bidirectional hybrid fiber-wireless systems with RF carrier frequencies at the W-band (75-110 GHz) that enables the seamless convergence between wireless and fiber-optic data transmission systems in access networks. In this study, we evaluate...... the transmission performances in two scenarios: a fiber-wireless access link that directly provide high-speed connections to wireless end users, and a fiber-wireless-fiber signal relay where a high capacity wireless link can be used to bridge two access fiber spans over physical obstacles. In both scenarios, we...

The Principle of Non-Refoulement and Access to Asylum System: Two Sides of the Same Coin

Directory of Open Access Journals (Sweden)

Goranka Lalić Novak

2015-12-01

Full Text Available The European Union and other countries on the Balkan route for migrants have recorded a large increase in the number of asylum seekers. In parallel with the increased number of refugees trying to enter the territory of the EU, measures for migration management have tightened, and the right to asylum at the level of the Member States has been interpreted more and more restrictive. Search for protection from persecution has become a reason for closing borders and disabling access to territory and asylum system. However, access to asylum system is the first step in the realization of the right to asylum as guaranteed by international, European and national law. In addition to allowing access to territory and asylum system, which implies an obligation of states to accept refugees in order to confirm the need for international protection in a fair and efficient procedure, the states are obliged to respect the principle of non-refoulement. The aim of this paper is to clarify the connection between providing access to asylum system and respect for the principle of non-refoulement. Analysis in the paper was done by legal-dogmatic method of research and interpretation of legal acts and other authorities, as well as of UNHCR relevant recommendations and documents. The assumption is that without the provision of access to territory and asylum system the principle of non-refoulement cannot be respected. Apart from the international refugee law and doctrinal interpretations, it derives from the practice of the European Court of Human Rights regarding the prohibition of torture or other inhuman treatment or punishment guaranteed by the Convention for the Protection of Human Rights and Fundamental Freedoms. The conclusion is that the states must take into account international and European standards regarding the protection of the principle of non-refoulement when considering the introduction of new measures to manage migration movements.

The NASA Astrophysics Data System Free Access to the Astronomical Literature On-Line and through Email

CERN Document Server

Eichhorn, G; Grant, C S; Kurtz, M J; Murray, S S

2001-01-01

The Astrophysics Data System (ADS) provides access to the astronomical literature through the World Wide Web. It is a NASA funded project and access to all the ADS services is free to everybody world-wide.The ADS Abstract Service allows the searching of four databases with abstracts in Astronomy, Instrumentation, Physics/Geophysics, and the LANL Preprints with a total of over 2.2 million references. The system also provides access to reference and citation information, links to on-line data, electronic journal articles, and other on-line information. The ADS Article Service contains the articles for most of the astronomical literature back to volume 1. It contains the scanned pages of all the major journals (Astrophysical Journal, Astronomical Journal, Astronomy & Astrophysics, Monthly Notices of the Royal Astronomical Society, and Solar Physics), as well as most smaller journals back to volume 1. The ADS can be accessed through any web browser without signup or login. Alternatively an email interface is ...

Professional Access 2013 programming

CERN Document Server

Hennig, Teresa; Hepworth, George; Yudovich, Dagi (Doug)

2013-01-01

Authoritative and comprehensive coverage for building Access 2013 Solutions Access, the most popular database system in the world, just opened a new frontier in the Cloud. Access 2013 provides significant new features for building robust line-of-business solutions for web, client and integrated environments.  This book was written by a team of Microsoft Access MVPs, with consulting and editing by Access experts, MVPs and members of the Microsoft Access team. It gives you the information and examples to expand your areas of expertise and immediately start to develop and upgrade projects. Exp

Access control and interlock system at the Advanced Photon Source

International Nuclear Information System (INIS)

Forrestal, J.; Hogrefe, R.; Knott, M.; McDowell, W.; Reigle, D.; Solita, L.; Koldenhoven, R.; Haid, D.

1997-01-01

The Advanced Photon Source (APS) consists of a linac, position accumulator ring (PAR), booster synchrotron, storage ring, and up to 70 experimental beamlines. The Access Control and Interlock System (ACIS) utilizes redundant programmable logic controllers (PLCs) and a third hard-wired chain to protect personnel from prompt radiation generated by the linac, PAR, synchrotron, and storage ring. This paper describes the ACIS's design philosophy, configuration, hardware, functionality, validation requirements, and operational experience

Design and Implementation of File Access and Control System Based on Dynamic Web

Institute of Scientific and Technical Information of China (English)

GAO Fuxiang; YAO Lan; BAO Shengfei; YU Ge

2006-01-01

A dynamic Web application, which can help the departments of enterprise to collaborate with each other conveniently, is proposed. Several popular design solutions are introduced at first. Then, dynamic Web system is chosen for developing the file access and control system. Finally, the paper gives the detailed process of the design and implementation of the system, which includes some key problems such as solutions of document management and system security. Additionally, the limitations of the system as well as the suggestions of further improvement are also explained.

28 CFR 16.71 - Exemption of the Office of the Deputy Attorney General System-limited access.

Science.gov (United States)

2010-07-01

... Attorney General System-limited access. 16.71 Section 16.71 Judicial Administration DEPARTMENT OF JUSTICE....71 Exemption of the Office of the Deputy Attorney General System—limited access. (a) The following... of the Office of the Deputy Attorney General (JUSTICE/DAG-013). (d) In addition, the Drug Enforcement...

Implications of access hole size on tank waste retrieval system design and cost

International Nuclear Information System (INIS)

Babcock, S.M.; Kwon, D.S.; Burks, B.L.; Stoughton, R.S.; Evans, M.S.

1994-05-01

The DOE Environmental Restoration and Waste Management Robotics Technology Development Program has been investigating the application of robotics technology to the retrieval of waste from single-shell storage tanks for several years. The use of a large, ''long-reach'' manipulator to position and orient a variety of tools and other equipment has been recommended. The objective of this study is to determine the appropriate access hole size for the tank waste retrieval system installation. Previous reports on the impact of access hole size on manipulator performance are summarized. In addition, the practical limitation for access hole size based on structural limitations of the waste storage tanks, the state-of-the-art size limitations for the installation of new risers, the radiation safety implications of various access hole sizes, and overall system cost implications are considered. Basic conclusions include: (1) overall cost of remediation will; be dominated by the costs of the balance of plant and time required to perform the task rather than the cost of manipulator hardware or the cost of installing a riser, (2) the most desirable solution from a manipulator controls point of view is to make the manipulator as stiff as possible and have as high as possible a natural frequency, which implies a large access hole diameter, (3) beyond some diameter; simple, uniform cross-section elements become less advantageous from a weight standpoint and alternative structures should be considered, and (4) additional shielding and contamination control measures would be required for larger holes. Parametric studies summarized in this report considered 3,790,000 1 (1,000,000 gal) tanks, while initial applications are likely to be for 2,840,000 1 (750,000 gal) tanks. Therefore, the calculations should be somewhat conservative, recognizing the limitations of the specific conditions considered

Electrical impedance tomography system: an open access circuit design

Directory of Open Access Journals (Sweden)

Soleimani Manuchehr

2006-05-01

Full Text Available Abstract Background This paper reports a simple 2-D system for electrical impedance tomography EIT, which works efficiently and is low cost. The system has been developed in the Sharif University of Technology Tehran-Iran (for the author's MSc Project. Methods The EIT system consists of a PC in which an I/O card is installed with an external current generator, a multiplexer, a power supply and a phantom with an array of electrodes. The measurement system provides 12-bit accuracy and hence, suitable data acquisition software has been prepared accordingly. The synchronous phase detection method has been implemented for voltage measurement. Different methods of image reconstruction have been used with this instrument to generate electrical conductivity images. Results The results of simulation and real measurement of the system are presented. The reconstruction programs were written in MATLAB and the data acquisition software in C++. The system has been tested with both static and dynamic mode in a 2-D domain. Better results have been produced in the dynamic mode of operation, due to the cancellation of errors. Conclusion In the spirit of open access publication the design details of this simple EIT system are made available here.

The promise of downlink MU-MIMO for high-capacity next generation mobile broadband networks based on IEEE 802.16 m

Directory of Open Access Journals (Sweden)

Papathanassiou Apostolos

2011-01-01

Full Text Available Abstract The dramatic increase of the demand for mobile broadband services poses stringent requirements on the performance evolution of currently deployed mobile broadband networks, such as Mobile WiMAX Release 1 and 3GPP LTE Release 8. Although the combination of single-user multiple-input multiple-output (SU-MIMO and orthogonal frequency division multiple access (OFDMA provide the appropriate technologies for improving the downlink performance of third generation (3G code division multiple access (CDMA-based mobile radio systems and, thus, address the current mobile internet requirements, a fundamental paradigm shift is required to cope with the constantly increasing mobile broadband data rate and spectral efficiency requirements. Among the different technologies available for making the paradigm shift from current to next-generation mobile broadband networks, multiuser MIMO (MU-MIMO constitutes the most promising technology because of its significant performance improvement advantages. In this article, we analyze the performance of MU-MIMO under a multitude of deployment scenarios and system parameters through extensive system-level simulations which are based on widely used system-level evaluation methodologies. The target mobile broadband system used in the simulations is IEEE 802.16 m which was recently adopted by ITU-R as an IMT-Advanced technology along with 3GPP LTE-Advanced. The results provide insights into different aspects of MU-MIMO with respect to system-level performance, parameter sensitivity, and deployment scenarios, and they can be used by the mobile broadband network designer for maximizing the benefits of MU-MIMO in a scenario with specific deployment requirements and goals.

A Real-time License Plate Detection System for Parking Access

Directory of Open Access Journals (Sweden)

Roenadi Koesdijarto

2010-08-01

Full Text Available The automatic and real-time license plate detection system can be used as an access control entry of vehicles into the parking area. The problem is how to recognize the vehicles that will go into the parking lot and how to recognize various types of license plates in various light conditions quickly and accurately. In this research, the prototype was developed with a detection system to recognize the vehicles that will enter the parking area, and a license plate recognition system. In the license plate recognition system, the Fourier transform and Hidden Markov model method have proposed to detect location of license plate and as characters segmentation to recognize Indonesia license plates. The research results have shown that the developed prototype system has successfully recognized all Indonesia license plates in several of light condition and camera position. The percentage of plate recognition in the real-time experiment is 84.38%, and the average execution time for all recognition process is 5.834 second.

Evaluation on the Occupational Information Access System as Used at Churchill High School. A Project Report.

Science.gov (United States)

McKinlay, Bruce; Adams, Daniel

The Occupational Information Access System (OIAS) improves the accessibility of occupational labor market information for career planning. Its operation at Churchill High School is evaluated from several angels: the likes and dislikes of users; the effect of OIAS on users' knowledge of occupational information and on their career plans; why other…

Assessing the impact of a medical image access system

Science.gov (United States)

McNeill, Kevin M.; Maloney, Kris; Parra, Miguel V.; Ovitt, Theron W.; Dallas, William J.

1994-05-01

We have developed and installed a Medical Image Access System in an intensive care unit. Images are acquired and transmitted automatically to this system, thus expanding on the previous results of Shile et. al. It is our goal to determine what effect regular, sustained availability of image data in the clinic has on the Intensive Care Unit and the Department of Radiology. Our system is installed and has been in regular use in the hospital since late August of 1993. Since the time of installation we have been collecting usage information from both the manual and automated systems. From this data we are performing the standard measures established by DeSimone et. al. Our initial results support the original findings that image availability in the clinic leads to earlier patient care decision based on the image data. However, our findings do not seem to indicate that there is a breakdown of communication between the clinician and the radiologist as a result of the use of the clinical display system. In addition to the established measure we are investigating other criteria to measure time saved by both the clinician and radiologist. The results are reported in this paper.

Preconceptual systems and equipment for plugging of man-made accesses to a repository in basalt

International Nuclear Information System (INIS)

Taylor, C.L.; O'Rourke, J.E.; Allirot, D.; O'Connor, K.

1980-09-01

This report presents results of a study leading to preconceptual designs for plugging boreholes, shafts, and tunnels to a nuclear waste repository in basalt. Beginning design criteria include a list of preferred plug materials and plugging machines that were selected to suit the environmental conditions, and depths, diameters, and orientations of the accesses to a nuclear waste repository in the Columbia River basalts located in eastern Washington State. The environmental conditions are described. The fiscal year 1979-1980 Task II work is presented in two parts: preliminary testing of materials for plugging of man-made accesses to a repository in basalt (described in a separate report); and preconceptual systems and equipment for plugging of man-made accesses to a repository in basalt (described in this report). To fulfill the scope of the Task II work, Woodward-Clyde Consultants (WCC) was requested to: provide preconceptual systems for plugging boreholes, tunnels, and shafts in basalt; describe preconceptual borehole plugging equipment for placing the selected materials in man-made accesses; utilize the quality assurance program, program plan and schedule, and work plans previously developed for Task II; and prepare a preliminary report

Flexible Access Control for Dynamic Collaborative Environments

NARCIS (Netherlands)

Dekker, M.A.C.

2009-01-01

Access control is used in computer systems to control access to confidential data. In this thesis we focus on access control for dynamic collaborative environments where multiple users and systems access and exchange data in an ad hoc manner. In such environments it is difficult to protect

Complementary role of two evaluation methods in the usability and accessibility evaluation of a non-standard system

CSIR Research Space (South Africa)

Adebesin, F

2010-10-01

Full Text Available and used by people with varying abilities. Although accessibility concerns are aimed at making systems usable for people with disabilities, support for direct accessibility, the built-in redundancies in an application that enable as many people as possible...

Access to medication in the Public Health System and equity: populational health surveys in São Paulo, Brazil.

Science.gov (United States)

Monteiro, Camila Nascimento; Gianini, Reinaldo José; Barros, Marilisa Berti de Azevedo; Cesar, Chester Luiz Galvão; Goldbaum, Moisés

2016-03-01

Since 2003, the access to medication has been increasing in Brazil and particularly in São Paulo. The present study aimed to analyze the access to medication obtained in the public sector and the socioeconomic differences in this access in 2003 and 2008. Also, we explored the difference in access to medication from 2003 to 2008. Data were obtained from two cross-sectional population-based household surveys from São Paulo, Brazil (ISA-Capital 2003 and ISA-Capital 2008). Concentration curve and concentration index were calculated to analyze the associations between socioeconomic factors and access to medication in the public sector. Additionally, the differences between 2003 and 2008 regarding socioeconomic characteristics and access to medication were studied. Access to medication was 89.55% in 2003 and 92.99% in 2008, and the proportion of access to medication did not change in the period. Access in the public sector increased from 26.40% in 2003 to 48.55% in 2008 and there was a decrease in the concentration index between 2003 and 2008 in access to medication in the public sector. The findings indicate an expansion of Brazilian Unified Health System (Sistema Único de Saúde ) users, with the inclusion of people of higher socioeconomic position in the public sector. As the SUS gives more support to people of lower socioeconomic position in terms of medication provision, the SUS tends to equity. Nevertheless, universal coverage for medication and equity in access to medication in the public sector are still challenges for the Brazilian public health system.

Design of a control system for self-shielded irradiators with remote access capability

International Nuclear Information System (INIS)

Iyengar, R.D.; Verma, P.B.; Prasad, V.V.S.S.; George, Jain R.; Das, Tripti; Deshmukh, D.K.

2001-01-01

With self-shielded irradiators like Gamma chambers, and Blood irradiators are being sold by BRIT to customers both within and outside the country, it has become necessary to improve the quality of service without increasing the overheads. The recent advances in the field of communications and information technology can be exploited for improving the quality of service to the customers. A state of the art control system with remote accessibility has been designed for these irradiators enhancing their performance. This will provide an easy access to these units wherever they might be located, through the Internet. With this technology it will now be possible to attend to the needs of the customers, as regards fault rectification, error debugging, system software update, performance testing, data acquisition etc. This will not only reduce the downtime of these irradiators but also reduce the overheads. (author)

Beat Noise Cancellation in 2-D Optical Code-Division Multiple-Access Systems Using Optical Hard-Limiter Array

Science.gov (United States)

Dang, Ngoc T.; Pham, Anh T.; Cheng, Zixue

We analyze the beat noise cancellation in two-dimensional optical code-division multiple-access (2-D OCDMA) systems using an optical hard-limiter (OHL) array. The Gaussian shape of optical pulse is assumed and the impact of pulse propagation is considered. We also take into account the receiver noise and multiple access interference (MAI) in the analysis. The numerical results show that, when OHL array is employed, the system performance is greatly improved compared with the cases without OHL array. Also, parameters needed for practical system design are comprehensively analyzed.

75 FR 47464 - Exemption to Prohibition on Circumvention of Copyright Protection Systems for Access Control...

Science.gov (United States)

2010-08-06

... Prohibition on Circumvention of Copyright Protection Systems for Access Control Technologies AGENCY: Copyright... nonsubstantial correction to its regulation announcing the prohibition against circumvention of technological... the final rule governing exemption to prohibition on circumvention of copyright protection systems for...

Notified Access: Extending Remote Memory Access Programming Models for Producer-Consumer Synchronization

KAUST Repository

Belli, Roberto; Hoefler, Torsten

2015-01-01

Remote Memory Access (RMA) programming enables direct access to low-level hardware features to achieve high performance for distributed-memory programs. However, the design of RMA programming schemes focuses on the memory access and less on the synchronization. For example, in contemporary RMA programming systems, the widely used producer-consumer pattern can only be implemented inefficiently, incurring in an overhead of an additional round-trip message. We propose Notified Access, a scheme where the target process of an access can receive a completion notification. This scheme enables direct and efficient synchronization with a minimum number of messages. We implement our scheme in an open source MPI-3 RMA library and demonstrate lower overheads (two cache misses) than other point-to-point synchronization mechanisms for each notification. We also evaluate our implementation on three real-world benchmarks, a stencil computation, a tree computation, and a Colicky factorization implemented with tasks. Our scheme always performs better than traditional message passing and other existing RMA synchronization schemes, providing up to 50% speedup on small messages. Our analysis shows that Notified Access is a valuable primitive for any RMA system. Furthermore, we provide guidance for the design of low-level network interfaces to support Notified Access efficiently.

Notified Access: Extending Remote Memory Access Programming Models for Producer-Consumer Synchronization

KAUST Repository

Belli, Roberto

2015-05-01

Remote Memory Access (RMA) programming enables direct access to low-level hardware features to achieve high performance for distributed-memory programs. However, the design of RMA programming schemes focuses on the memory access and less on the synchronization. For example, in contemporary RMA programming systems, the widely used producer-consumer pattern can only be implemented inefficiently, incurring in an overhead of an additional round-trip message. We propose Notified Access, a scheme where the target process of an access can receive a completion notification. This scheme enables direct and efficient synchronization with a minimum number of messages. We implement our scheme in an open source MPI-3 RMA library and demonstrate lower overheads (two cache misses) than other point-to-point synchronization mechanisms for each notification. We also evaluate our implementation on three real-world benchmarks, a stencil computation, a tree computation, and a Colicky factorization implemented with tasks. Our scheme always performs better than traditional message passing and other existing RMA synchronization schemes, providing up to 50% speedup on small messages. Our analysis shows that Notified Access is a valuable primitive for any RMA system. Furthermore, we provide guidance for the design of low-level network interfaces to support Notified Access efficiently.

An Access Control Framework for Reflective Middleware

Institute of Scientific and Technical Information of China (English)

Gang Huang; Lian-Shan Sun

2008-01-01

Reflective middleware opens up the implementation details of middleware platform and applications at runtime for improving the adaptability of middleware-based systems. However, such openness brings new challenges to access control of the middleware-based systems.Some users can access the system via reflective entities, which sometimes cannot be protected by access control mechanisms of traditional middleware. To deliver high adaptability securely, reflective middleware should be equipped with proper access control mechanisms for potential access control holes induced by reflection. One reason of integrating these mechanisms in reflective middleware is that one goal of reflective middleware is to equip applications with reflection capabilities as transparent as possible. This paper studies how to design a reflective J2EE middlewarePKUAS with access control in mind. At first, a computation model of reflective system is built to identify all possible access control points induced by reflection. Then a set of access control mechanisms, including the wrapper of MBeans and a hierarchy of Java class loaders, are equipped for controlling the identified access control points. These mechanisms together with J2EE access control mechanism form the access control framework for PKUAS. The paper evaluates the security and the performance overheads of the framework in quality and quantity.

Accessibility

DEFF Research Database (Denmark)

Brooks, Anthony Lewis

2017-01-01

This contribution is timely as it addresses accessibility in regards system hardware and software aligned with introduction of the Twenty-First Century Communications and Video Accessibility Act (CVAA) and adjoined game industry waiver that comes into force January 2017. This is an act created...... by the USA Federal Communications Commission (FCC) to increase the access of persons with disabilities to modern communications, and for other purposes. The act impacts advanced communications services and products including text messaging; e-mail; instant messaging; video communications; browsers; game...... platforms; and games software. However, the CVAA has no legal status in the EU. This text succinctly introduces and questions implications, impact, and wider adoption. By presenting the full CVAA and game industry waiver the text targets to motivate discussions and further publications on the subject...

Enhancing Access to Drought Information Using the CUAHSI Hydrologic Information System

Science.gov (United States)

Schreuders, K. A.; Tarboton, D. G.; Horsburgh, J. S.; Sen Gupta, A.; Reeder, S.

2011-12-01

The National Drought Information System (NIDIS) Upper Colorado River Basin pilot study is investigating and establishing capabilities for better dissemination of drought information for early warning and management. As part of this study we are using and extending functionality from the Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI) Hydrologic Information System (HIS) to provide better access to drought-related data in the Upper Colorado River Basin. The CUAHSI HIS is a federated system for sharing hydrologic data. It is comprised of multiple data servers, referred to as HydroServers, that publish data in a standard XML format called Water Markup Language (WaterML), using web services referred to as WaterOneFlow web services. HydroServers can also publish geospatial data using Open Geospatial Consortium (OGC) web map, feature and coverage services and are capable of hosting web and map applications that combine geospatial datasets with observational data served via web services. HIS also includes a centralized metadata catalog that indexes data from registered HydroServers and a data access client referred to as HydroDesktop. For NIDIS, we have established a HydroServer to publish drought index values as well as the input data used in drought index calculations. Primary input data required for drought index calculation include streamflow, precipitation, reservoir storages, snow water equivalent, and soil moisture. We have developed procedures to redistribute the input data to the time and space scales chosen for drought index calculation, namely half monthly time intervals for HUC 10 subwatersheds. The spatial redistribution approaches used for each input parameter are dependent on the spatial linkages for that parameter, i.e., the redistribution procedure for streamflow is dependent on the upstream/downstream connectivity of the stream network, and the precipitation redistribution procedure is dependent on elevation to account

Pro Access 2010 Development

CERN Document Server

Collins, Mark

2011-01-01

Pro Access 2010 Development is a fundamental resource for developing business applications that take advantage of the features of Access 2010 and the many sources of data available to your business. In this book, you'll learn how to build database applications, create Web-based databases, develop macros and Visual Basic for Applications (VBA) tools for Access applications, integrate Access with SharePoint and other business systems, and much more. Using a practical, hands-on approach, this book will take you through all the facets of developing Access-based solutions, such as data modeling, co

New capabilities in the HENP grand challenge storage access system and its application at RHIC

International Nuclear Information System (INIS)

Bernardo, L.; Gibbard, B.; Malon, D.; Nordberg, H.; Olson, D.; Porter, R.; Shoshani, A.; Sim, A.; Vaniachine, A.; Wenaus, T.; Wu, K.; Zimmerman, D.

2000-01-01

The High Energy and Nuclear Physics Data Access Grand Challenge project has developed an optimizing storage access software system that was prototyped at RHIC. It is currently undergoing integration with the STAR experiment in preparation for data taking that starts in mid-2000. The behavior and lessons learned in the RHIC Mock Data Challenge exercises are described as well as the observed performance under conditions designed to characterize scalability. Up to 250 simultaneous queries were tested and up to 10 million events across 7 event components were involved in these queries. The system coordinates the staging of ''bundles'' of files from the HPSS tape system, so that all the needed components of each event are in disk cache when accessed by the application software. The caching policy algorithm for the coordinated bundle staging is described in the paper. The initial prototype implementation interfaced to the Objectivity/DB. In this latest version, it evolved to work with arbitrary files and use CORBA interfaces to the tag database and file catalog services. The interface to the tag database and the MySQL-based file catalog services used by STAR are described along with the planned usage scenarios

Remote access to an interferometric fringes stabilization active system via RENATA

Science.gov (United States)

Espitia-Gómez, Javier; Ángel-Toro, Luciano

2013-11-01

The Advanced Technology National Network (RENATA, for its acronym in Spanish) is a Colombian, collaborative work tool, linked to other networks worldwide, in which take participation researchers, teachers and students, by sharing laboratory resources located in different universities, institutes and research centers throughout the country. In the Universidad EAFIT (Medellín, Colombia) it has been designed an interferometric fringes stabilization active system, which can be accessed remotely via the RENATA network. A Mach-Zehnder interferometer was implemented, with independent piezoelectric actuators in each arm, with which the lengths of optical path of light that goes over in each of them can be modified. Using these actuators, one can simultaneously perturb the system and compensate the phase differences caused by that perturbation. This allows us to experiment with different disturbs, and analyze the system response to each one of them. This can be made from any location worldwide, and especially from those regions in which optical and optoelectronic components required for the implementation of the interferometer or for the stabilization system are not available. The device can also be used as a platform in order to conduct diverse experiments, involving optical and controlling aspects, constituting with this in a pedagogic tool. For the future, it can be predicted that remote access to available applications would be possible, as well as modifications of the implemented code in labVIEW™, so that researchers and teachers can adapt and improve their functionalities or develop new applications, based on the collaborative work.

FODA/IBEA satellite access scheme for MIXED traffic at variable bit and coding rates system description

OpenAIRE

Celandroni, Nedo; Ferro, Erina; Mihal, Vlado; Potort?, Francesco

1992-01-01

This report describes the FODA system working at variable coding and bit rates (FODA/IBEA-TDMA) FODA/IBEA is the natural evolution of the FODA-TDMA satellite access scheme working at 2 Mbit/s fixed rate with data 1/2 coded or uncoded. FODA-TDMA was used in the European SATINE-II experiment [8]. We remind here that the term FODA/IBEA system is comprehensive of the FODA/IBEA-TDMA (1) satellite access scheme and of the hardware prototype realised by the Marconi R.C. (U.K.). Both of them come fro...

Low Access Delay Anti-Collision Algorithm for Reader in RFID systems

DEFF Research Database (Denmark)

Galiotto, Carlo; Marchetti, Nicola; Prasad, Neeli R.

2010-01-01

Radio Frequency Identification (RFID) is a technology which is spreading more and more as a medium to identify, locate and track assets through the productive chain. As all the wireless communication devices sharing the same transmission channel, RFID readers and tags experience collisions whenever...... deployed over the same area. In this work, the RFID reader collision problem is studied and a centralized scheduling-based algorithm is proposed as possible candidate solution, especially for those scenarios involving static or low mobility readers. Taking into account the circuitry limitations of the tags......, which do not allow to use frequency or code division multiple access schemes in the RFID systems, this paper proposes an algorithm aiming to prevent the readers collisions, while keeping the access delay of the readers to the channel possibly low. The simulation results show that this algorithm performs...

A new model with an anatomically accurate human renal collecting system for training in fluoroscopy-guided percutaneous nephrolithotomy access.

Science.gov (United States)

Turney, Benjamin W

2014-03-01

Obtaining renal access is one of the most important and complex steps in learning percutaneous nephrolithotomy (PCNL). Ideally, this skill should be practiced outside the operating room. There is a need for anatomically accurate and cheap models for simulated training. The objective was to develop a cost-effective, anatomically accurate, nonbiologic training model for simulated PCNL access under fluoroscopic guidance. Collecting systems from routine computed tomography urograms were extracted and reformatted using specialized software. These images were printed in a water-soluble plastic on a three-dimensional (3D) printer to create biomodels. These models were embedded in silicone and then the models were dissolved in water to leave a hollow collecting system within a silicone model. These PCNL models were filled with contrast medium and sealed. A layer of dense foam acted as a spacer to replicate the tissues between skin and kidney. 3D printed models of human collecting systems are a useful adjunct in planning PCNL access. The PCNL access training model is relatively low cost and reproduces the anatomy of the renal collecting system faithfully. A range of models reflecting the variety and complexity of human collecting systems can be reproduced. The fluoroscopic triangulation process needed to target the calix of choice can be practiced successfully in this model. This silicone PCNL training model accurately replicates the anatomic architecture and orientation of the human renal collecting system. It provides a safe, clean, and effective model for training in accurate fluoroscopy-guided PCNL access.

Get the right access rights!

CERN Multimedia

Rosaria Marraffino

2015-01-01

On 11 May, a major change concerning the requirements to access the CERN beam facilities was put in place and implemented in ADaMS in order to reduce the number of courses that people who need access to multiple installations have to follow. This revision includes dedicated safety training courses that replace, in particular, the “Safety during LS1” e-learning course, which is now to be considered obsolete.   CERN’s Access Distribution and Management System (ADaMS). As of 11 May, an important improvement was implemented in ADaMS (CERN’s Access Distribution and Management System) regarding the requisites to access safety zones. This change is closely related to the introduction of a generic e-learning course ("CERN Beam Facilities") covering the common risks and systems present in CERN's beam facilities. Two e-learning courses are no longer valid, nor available on the SIR (Safety Information Registration) catalogue: the &ld...

Method for Evaluation of Outage Probability on Random Access Channel in Mobile Communication Systems

Science.gov (United States)

Kollár, Martin

2012-05-01

In order to access the cell in all mobile communication technologies a so called random-access procedure is used. For example in GSM this is represented by sending the CHANNEL REQUEST message from Mobile Station (MS) to Base Transceiver Station (BTS) which is consequently forwarded as an CHANNEL REQUIRED message to the Base Station Controller (BSC). If the BTS decodes some noise on the Random Access Channel (RACH) as random access by mistake (so- called ‘phantom RACH') then it is a question of pure coincidence which èstablishment cause’ the BTS thinks to have recognized. A typical invalid channel access request or phantom RACH is characterized by an IMMEDIATE ASSIGNMENT procedure (assignment of an SDCCH or TCH) which is not followed by sending an ESTABLISH INDICATION from MS to BTS. In this paper a mathematical model for evaluation of the Power RACH Busy Threshold (RACHBT) in order to guaranty in advance determined outage probability on RACH is described and discussed as well. It focuses on Global System for Mobile Communications (GSM) however the obtained results can be generalized on remaining mobile technologies (ie WCDMA and LTE).

Distributed Multi-Sensor Real-Time Building Environmental Parameters Monitoring System with Remote Data Access

Directory of Open Access Journals (Sweden)

Beinarts Ivars

2014-12-01

Full Text Available In this paper the advanced monitoring system of multiple environmental parameters is presented. The purpose of the system is a long-term estimation of energy efficiency and sustainability for the research test stands which are made of different building materials. Construction of test stands, and placement of main sensors are presented in the first chapter. The structure of data acquisition system includes a real-time interface with sensors and a data logger that allows to acquire and log data from all sensors with fixed rate. The data logging system provides a remote access to the processing of the acquired data and carries out periodical saving at a remote FTP server using an Internet connection. The system architecture and the usage of sensors are explained in the second chapter. In the third chapter implementation of the system, different interfaces of sensors and energy measuring devices are discussed and several examples of data logger program are presented. Each data logger is reading data from analog and digital channels. Measurements can be displayed directly on a screen using WEB access or using data from FTP server. Measurements and acquired data graphical results are presented in the fourth chapter in the selected diagrams. The benefits of the developed system are presented in the conclusion.

智能门禁系统设计要点探讨%Discussion on the Design of Intelligent Access Control System

Institute of Scientific and Technical Information of China (English)

朱矩龙

2015-01-01

Access control system is the basis and security of the use of building security, the use of advanced technology to design intelligent access control system is conducive to improve the safety of the building. Discusses a based on TM card intelligent access control system design, expounds the main problems existing in traditional access control system, comprehensive description of the hardware design and software design of the intelligent access control system, and the system is simulated and tested.%门禁系统是建筑使用安全性的基础和保障，使用先进技术对智能门禁系统进行设计有利于提高建筑的安全性能。探讨了一种基于TM卡技术的智能门禁系统设计，阐述了传统门禁系统存在的主要问题，综合说明了智能门禁系统的硬件设计和软件设计，并对系统进行了仿真测试。

Design of Nutrition Catering System for Athletes Based on Access Database

OpenAIRE

Hongjiang Wu,; Haiyan Zhao; Xugang Liu; Mingshun Xing

2015-01-01

In order to monitor and adjust athletes' dietary nutrition scientifically, Active X Data Object (ADO) and Structure Query Language (SQL) were used to produce program under the development environment of Visual Basic 6.0 and Access database. The consulting system on food nutrition and dietary had been developed with the two languages combination and organization of the latest nutrition information. Nutrition balance of physiological characteristics, assessment for nutrition intake, inquiring n...

On-Chip Fluorescence Switching System for Constructing a Rewritable Random Access Data Storage Device.

Science.gov (United States)

Nguyen, Hoang Hiep; Park, Jeho; Hwang, Seungwoo; Kwon, Oh Seok; Lee, Chang-Soo; Shin, Yong-Beom; Ha, Tai Hwan; Kim, Moonil

2018-01-10

We report the development of on-chip fluorescence switching system based on DNA strand displacement and DNA hybridization for the construction of a rewritable and randomly accessible data storage device. In this study, the feasibility and potential effectiveness of our proposed system was evaluated with a series of wet experiments involving 40 bits (5 bytes) of data encoding a 5-charactered text (KRIBB). Also, a flexible data rewriting function was achieved by converting fluorescence signals between "ON" and "OFF" through DNA strand displacement and hybridization events. In addition, the proposed system was successfully validated on a microfluidic chip which could further facilitate the encoding and decoding process of data. To the best of our knowledge, this is the first report on the use of DNA hybridization and DNA strand displacement in the field of data storage devices. Taken together, our results demonstrated that DNA-based fluorescence switching could be applicable to construct a rewritable and randomly accessible data storage device through controllable DNA manipulations.

Development of Remote Monitoring and a Control System Based on PLC and WebAccess for Learning Mechatronics

OpenAIRE

Wen-Jye Shyr; Te-Jen Su; Chia-Ming Lin

2013-01-01

This study develops a novel method for learning mechatronics using remote monitoring and control, based on a programmable logic controller (PLC) and WebAccess. A mechatronics module, a Web‐CAM and a PLC were integrated with WebAccess software to organize a remote laboratory. The proposed system enables users to access the Internet for remote monitoring and control of the mechatronics module via a web browser, thereby enhancing work flexibility by enabling personnel to control mechatronics equ...

Wireless Broadband Access and Accounting Schemes

Institute of Scientific and Technical Information of China (English)

无

2003-01-01

In this paper, we propose two wireless broadband access and accounting schemes. In both schemes, the accounting system adopts RADIUS protocol, but the access system adopts SSH and SSL protocols respectively.

Access Control Based on Trail Inference

Directory of Open Access Journals (Sweden)

ALBARELO, P. C.

2015-06-01

Full Text Available Professionals are constantly seeking qualification and consequently increasing their knowledge in their area of expertise. Thus, it is interesting to develop a computer system that knows its users and their work history. Using this information, even in the case of professional role change, the system could allow the renewed authorization for activities, based on previously authorized use. This article proposes a model for user access control that is embedded in a context-aware environment. The model applies the concept of trails to manage access control, recording activities usage in contexts and applying this history as a criterion to grant new accesses. Despite the fact that previous related research works consider contexts, none of them uses the concept of trails. Hence, the main contribution of this work is the use of a new access control criterion, namely, the history of previous accesses (trails. A prototype was implemented and applied in an evaluation based on scenarios. The results demonstrate the feasibility of the proposal, allowing for access control systems to use an alternative way to support access rights.

Perti Net-Based Workflow Access Control Model

Institute of Scientific and Technical Information of China (English)

陈卓; 骆婷; 石磊; 洪帆

2004-01-01

Access control is an important protection mechanism for information systems. This paper shows how to make access control in workflow system. We give a workflow access control model (WACM) based on several current access control models. The model supports roles assignment and dynamic authorization. The paper defines the workflow using Petri net. It firstly gives the definition and description of the workflow, and then analyzes the architecture of the workflow access control model (WACM). Finally, an example of an e-commerce workflow access control model is discussed in detail.

Test-Access Planning and Test Scheduling for Embedded Core-Based System Chips

OpenAIRE

Goel, Sandeep Kumar

2005-01-01

Advances in the semiconductor process technology enable the creation of a complete system on one single die, the so-called system chip or SOC. To reduce time-to-market for large SOCs, reuse of pre-designed and pre-veried blocks called cores is employed. Like the design style, testing of SOCs can be best approached in a core-based fashion. In order to enable core-based test development, an embedded core should be isolated from its surrounding circuitry and electrical test access from chip pins...

A web accessible scientific workflow system for vadoze zone performance monitoring: design and implementation examples

Science.gov (United States)

Mattson, E.; Versteeg, R.; Ankeny, M.; Stormberg, G.

2005-12-01

Long term performance monitoring has been identified by DOE, DOD and EPA as one of the most challenging and costly elements of contaminated site remedial efforts. Such monitoring should provide timely and actionable information relevant to a multitude of stakeholder needs. This information should be obtained in a manner which is auditable, cost effective and transparent. Over the last several years INL staff has designed and implemented a web accessible scientific workflow system for environmental monitoring. This workflow environment integrates distributed, automated data acquisition from diverse sensors (geophysical, geochemical and hydrological) with server side data management and information visualization through flexible browser based data access tools. Component technologies include a rich browser-based client (using dynamic javascript and html/css) for data selection, a back-end server which uses PHP for data processing, user management, and result delivery, and third party applications which are invoked by the back-end using webservices. This system has been implemented and is operational for several sites, including the Ruby Gulch Waste Rock Repository (a capped mine waste rock dump on the Gilt Edge Mine Superfund Site), the INL Vadoze Zone Research Park and an alternative cover landfill. Implementations for other vadoze zone sites are currently in progress. These systems allow for autonomous performance monitoring through automated data analysis and report generation. This performance monitoring has allowed users to obtain insights into system dynamics, regulatory compliance and residence times of water. Our system uses modular components for data selection and graphing and WSDL compliant webservices for external functions such as statistical analyses and model invocations. Thus, implementing this system for novel sites and extending functionality (e.g. adding novel models) is relatively straightforward. As system access requires a standard webbrowser

Global system data bus using the Digital Autonomous Terminal Access Communication protocol

Science.gov (United States)

Holmes, David C. E.

1986-01-01

Modern digital avionic systems with distributed processing require networking to connect the many elements. Digital Autonomous Terminal Access Communication (DATAC) is one of many such networks. DATAC has been implemented on the Transport Systems Research Vehicle (TSRV), a Boeing 737 aircraft operated by the National Aeronautics and Space Administration's Advanced Transport Operating Systems Program Office (ATOPS). This paper presents the TSRV implementation of the DATAC bus, a description of the DATAC system, a synchronization mechanism, details of data flow throughout the system, and a discussion of the modes available with DATAC. Numerous flight tests have been conducted using DATAC as the only means of communication between systems with outstanding results. DATAC is now an integral part of the TSRV and is expected to satisfy near term as well as future requirements for growth and flexibility.

Dual-mode ultraflow access networks: a hybrid solution for the access bottleneck

Science.gov (United States)

Kazovsky, Leonid G.; Shen, Thomas Shunrong; Dhaini, Ahmad R.; Yin, Shuang; De Leenheer, Marc; Detwiler, Benjamin A.

2013-12-01

Optical Flow Switching (OFS) is a promising solution for large Internet data transfers. In this paper, we introduce UltraFlow Access, a novel optical access network architecture that offers dual-mode service to its end-users: IP and OFS. With UltraFlow Access, we design and implement a new dual-mode control plane and a new dual-mode network stack to ensure efficient connection setup and reliable and optimal data transmission. We study the impact of the UltraFlow system's design on the network throughput. Our experimental results show that with an optimized system design, near optimal (around 10 Gb/s) OFS data throughput can be attained when the line rate is 10Gb/s.

Open access to transmission

International Nuclear Information System (INIS)

Keith, D.M.

1996-01-01

For the past 12 to 15 years, the US electric power and energy industry and its federal regulators have been going through a prolonged exercise leading to opening up the national interconnected transmission grid for all qualified wholesale users to have open and equal access. The debates have been painful in a sense that not all parties - especially some of the transmission system owning utilities - believe that the concept of Open Access is achievable, due to technical constraints on the systems. The present Open Access activity is limited to wholesales transaction under the federal jurisdiction, but several states are either experimenting with or considering retail wheeling. In fact, the FERC - Federal Energy Regulatory Commission - has already expanded its view to embrace retail transmission, if the retail transaction involves the use of the interstate transmission systems which are under FERC's jurisdiction. This paper delves into some of the results of the technical cost and pricing analysis for open access. The statutes and resulting regulations are not addressed herein. (author). 1 fig

Employing optical code division multiple access technology in the all fiber loop vibration sensor system

Science.gov (United States)

Tseng, Shin-Pin; Yen, Chih-Ta; Syu, Rong-Shun; Cheng, Hsu-Chih

2013-12-01

This study proposes a spectral amplitude coding-optical code division multiple access (SAC-OCDMA) framework to access the vibration frequency of a test object on the all fiber loop vibration sensor (AFLVS). Each user possesses an individual SAC, and fiber Bragg grating (FBG) encoders/decoders using multiple FBG arrays were adopted, providing excellent orthogonal properties in the frequency domain. The system also mitigates multiple access interference (MAI) among users. When an optical fiber is bent to a point exceeding the critical radius, the fiber loop sensor becomes sensitive to external physical parameters (e.g., temperature, strain, and vibration). The AFLVS involves placing a fiber loop with a specific radius on a designed vibration platform.

Microsoft DirectAccess best practices and troubleshooting

CERN Document Server

Krause, Jordan

2013-01-01

This book covers best practices and acts as a complete guide to DirectAccess and automatic remote access.Microsoft DirectAccess Best Practices and Troubleshooting is an ideal guide for any existing or future DirectAccess administrator and system administrators who are working on Windows Server 2012. This book will also be beneficial for someone with a basic knowledge of networking and deployment of Microsoft operating systems and software who wants to learn the intricacies of DirectAccess and its interfaces.

Identity and Access Management and Security in Higher Education.

Science.gov (United States)

Bruhn, Mark; Gettes, Michael; West, Ann

2003-01-01

Discusses the drivers for an identity management system (IdM), components of this system, and its role within a school security strategy, focusing on: basic access management; requirements for access management; middleware support for an access management system; IdM implementation considerations (e.g., access eligibilities, authentication…

La Resolución de problemas mediante el sistema de aplicación Microsoft Access Problem solving by means of Microsoft Access application system

Directory of Open Access Journals (Sweden)

Pablo González Ruíz

2010-03-01

and to carry out relationships among these; that is why it is necessary to elaborate a system of exercises considering the levels of cognitive performance which contribute with the development of skills of problem-solving with computers, using Microsoft Access System, and taking into account the following aspects: the design or the table work as a basic premise ( Diagram entity- relation and the Model entity-relation. The system of exercises is based on a quasi-experimental study covering two groups of medical students in 1st academic year in the Medical University, Pinar del Rio municipality. The bases of this research paper are on lecture controls and knowledge checking, which show difficulties in problem-solving when using the Microsoft Access database. The newness of this system is that it envisages the exercises upon a developing perspective of the levels of cognitive performance. The essential conclusion stated is that, with the creation of this system the student will quickly get familiar with the concepts (tables, attributes, field, register, key field and others, before approaching to an informative system, that is to say, a better way of logic thinking is achieved, from the living contemplation to the abstract thinking and from this to the practice as a prove of truth.

Data access performance through parallelization and vectored access. Some results

International Nuclear Information System (INIS)

Furano, F; Hanushevsky, A

2008-01-01

High Energy Physics data processing and analysis applications typically deal with the problem of accessing and processing data at high speed. Recent studies, development and test work have shown that the latencies due to data access can often be hidden by parallelizing them with the data processing, thus giving the ability to have applications which process remote data with a high level of efficiency. Techniques and algorithms able to reach this result have been implemented in the client side of the Scalla/xrootd system, and in this contribution we describe the results of some tests done in order to compare their performance and characteristics. These techniques, if used together with multiple streams data access, can also be effective in allowing to efficiently and transparently deal with data repositories accessible via a Wide Area Network

A METHOD OF AND A SYSTEM FOR CONTROLLING ACCESS TO A SHARED RESOURCE

DEFF Research Database (Denmark)

2006-01-01

A method and a system of controlling access of data items to a shared resource, wherein the data items each is assigned to one of a plurality of priorities, and wherein, when a predetermined number of data items of a priority have been transmitted to the shared resource, that priority...

Hacking Blackboard: Customizing Access to Library Resources through the Blackboard Course Management System

Science.gov (United States)

Kellam, Lynda M.; Cox, Richard; Winkler, Hannah

2009-01-01

Academic libraries have long been trying to gain access to users through their favorite online spaces, such as social networking sites. In this article a project of the University of North Carolina at Greensboro's University Libraries, which integrated library resources with the campus course management system, Blackboard, is detailed. The main…

48 CFR 504.602-71 - Federal Procurement Data System-Public access to data.

Science.gov (United States)

2010-10-01

... Government procurement to the public. (b) Fee for direct hook-up. To the extent that a member of the public... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Federal Procurement Data... Procurement Data System—Public access to data. (a) The FPDS database. The General Services Administration...

NuDat system for access to nuclear data

International Nuclear Information System (INIS)

Dunford, C.L.; Kinsey, R.R.

1998-01-01

The NuDat program provides a user with access to nuclear properties and to some nuclear reaction data. The program operates on DEC VMS operating systems and on PC's with Microsoft operating systems. The program has four user interfaces, all having the same content and functionality. These interfaces are Web, Video and Sequential for VMS. The PC interface is identical to the VMS Video interface. Forms are used to supply the type of data the user desires, the retrieval parameters, the output format, and the sort order of the data. The program and associated database is used in basic research, particularly for the systematic study of nuclear properties. It is also a useful tool for applied research to identify radiations from radionuclides contained in environmental samples, or from those produced by neutron or charged particle activation. The NuDat database is derived from several databases maintained by the National Nuclear Data Center. The databases are the Adopted Levels and Gammas data sets from ENSDF, the Nuclear Wallet Cards, Decay Radiations derived from ENSDF decay data sets processed by RADLIST, and Thermal Neutron Cross Sections

28 CFR 16.70 - Exemption of the Office of the Attorney General System-limited access.

Science.gov (United States)

2010-07-01

....70 Exemption of the Office of the Attorney General System—limited access. (a) The following system of...); and (g): (1) General Files System of the Office of the Attorney General (JUSTICE/OAG-001). These... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Exemption of the Office of the Attorney...

A New Time-Hopping Multiple Access Communication System Simulator: Application to Ultra-Wideband

Directory of Open Access Journals (Sweden)

José M. Páez-Borrallo

2005-03-01

Full Text Available Time-hopping ultra-wideband technology presents some very attractive features for future indoor wireless systems in terms of achievable transmission rate and multiple access capabilities. This paper develops an algorithm to design time-hopping system simulators specially suitable for ultra-wideband, which takes advantage of some of the specific characteristics of this kind of systems. The algorithm allows an improvement of both the time capabilities and the achievable sampling rate and can be used to research into the influence of different parameters on the performance of the system. An additional result is the validation of a new general performance formula for time-hopping ultra-wideband systems with multipath channels.

Resource allocation via sum-rate maximization in the uplink of multi-cell OFDMA networks

KAUST Repository

Tabassum, Hina; Alouini, Mohamed-Slim; Dawy, Zaher

2012-01-01

In this paper, we consider maximizing the sum rate in the uplink of a multi-cell orthogonal frequency-division multiple access network. The problem has a non-convex combinatorial structure and is known to be NP-hard. Because of the inherent

Centralized optical-frequency-comb-based RF carrier generator for DWDM fiber-wireless access systems

DEFF Research Database (Denmark)

Pang, Xiaodan; Beltran, Marta; Sanchez, Jose

2014-01-01

In this paper, we report on a gigabit capacity fiber-wireless system that enables smooth integration between high-speed wireless networks and dense wavelength-division-multiplexing (DWDM) access networks. By employing a centralized optical frequency comb, both the wireline and the wireless services...

Mitigation of Beat Noise in Time Wavelength Optical Code-Division Multiple-Access Systems

Science.gov (United States)

Bazan, Taher M.; Harle, David; Andonovic, Ivan

2006-11-01

This paper presents an analysis of two methods for enhancing the performance of two-dimensional time wavelength Optical code-division multiple-access systems by mitigating the effects of beat noise. The first methodology makes use of an optical hard limiter (OHL) in the receiver prior to the optical correlator; a general formula for the error probability as a function of crosstalk level for systems adopting OHLs is given, and the implications of the OHL's nonideal transfer characteristics are then examined. The second approach adopts pulse position modulation, and system performance is estimated and compared to that associated with on off keying.

Exploring the drivers of health and healthcare access in Zambian prisons: a health systems approach.

Science.gov (United States)

Topp, Stephanie M; Moonga, Clement N; Luo, Nkandu; Kaingu, Michael; Chileshe, Chisela; Magwende, George; Heymann, S Jody; Henostroza, German

2016-11-01

Prison populations in sub-Saharan Africa (SSA) experience a high burden of disease and poor access to health care. Although it is generally understood that environmental conditions are dire and contribute to disease spread, evidence of how environmental conditions interact with facility-level social and institutional factors is lacking. This study aimed to unpack the nature of interactions and their influence on health and healthcare access in the Zambian prison setting. We conducted in-depth interviews of a clustered random sample of 79 male prisoners across four prisons, as well as 32 prison officers, policy makers and health care workers. Largely inductive thematic analysis was guided by the concepts of dynamic interaction and emergent behaviour, drawn from the theory of complex adaptive systems. A majority of inmates, as well as facility-based officers reported anxiety linked to overcrowding, sanitation, infectious disease transmission, nutrition and coercion. Due in part to differential wealth of inmates and their support networks on entering prison, and in part to the accumulation of authority and material wealth within prison, we found enormous inequity in the standard of living among prisoners at each site. In the context of such inequities, failure of the Zambian prison system to provide basic necessities (including adequate and appropriate forms of nutrition, or access to quality health care) contributed to high rates of inmate-led and officer-led coercion with direct implications for health and access to healthcare. This systems-oriented analysis provides a more comprehensive picture of the way resource shortages and human interactions within Zambian prisons interact and affect inmate and officer health. While not a panacea, our findings highlight some strategic entry-points for important upstream and downstream reforms including urgent improvement in the availability of human resources for health; strengthening of facility-based health services systems

EPICS: Channel Access security design

International Nuclear Information System (INIS)

Kraimer, M.; Hill, J.

1994-05-01

This document presents the design for implementing the requirements specified in: EPICS -- Channel Access Security -- functional requirements, Ned. D. Arnold, 03/09/92. Use of the access security system is described along with a summary of the functional requirements. The programmer's interface is given. Security protocol is described and finally aids for reading the access security code are provided

Equity for open-access journal publishing.

Directory of Open Access Journals (Sweden)

Stuart M Shieber

2009-08-01

Full Text Available Open-access journals, which provide access to their scholarly articles freely and without limitations, are at a systematic disadvantage relative to traditional closed-access journal publishing and its subscription-based business model. A simple, cost-effective remedy to this inequity could put open-access publishing on a path to become a sustainable, efficient system.

NUDAT. System for access to nuclear data. Summary description

International Nuclear Information System (INIS)

Dunford, C.L.; Kinsey, R.R.

1998-01-01

The NUDAT program with its associated database provides access to nuclear properties and some nuclear reaction data. The program has interfaces for WWW, Telnet online access, and PC. The database contains the following information: level and gamma-ray adopted properties from ENSDF; nuclear ground and metastable state properties; radioactive decay radiations from ENSDF; thermal neutron cross sections and resonance integrals as published in 'Neutron Cross Sections', Vol. 1. The online version is accessible through the IAEA's WWW site or through the Telnet online service NDIS, the PC version is available by FTP or on CD-ROM. (author)

40 CFR 267.34 - When must personnel have access to communication equipment or an alarm system?

Science.gov (United States)

2010-07-01

... to an internal alarm or emergency communication device, either directly or through visual or voice... communication equipment or an alarm system? 267.34 Section 267.34 Protection of Environment ENVIRONMENTAL... have access to communication equipment or an alarm system? (a) Whenever hazardous waste is being poured...

Single-centre experience with Renal PatientView, a web-based system that provides patients with access to their laboratory results.

Science.gov (United States)

Woywodt, Alexander; Vythelingum, Kervina; Rayner, Scott; Anderton, John; Ahmed, Aimun

2014-10-01

Renal PatientView (RPV) is a novel, web-based system in the UK that provides patients with access to their laboratory results, in conjunction with patient information. To study how renal patients within our centre access and use RPV. We sent out questionnaires in December 2011 to all 651 RPV users under our care. We collected information on aspects such as the frequency and timing of RPV usage, the parameters viewed by users, and the impact of RPV on their care. A total of 295 (45 %) questionnaires were returned. The predominant users of RPV were transplant patients (42 %) followed by pre-dialysis chronic kidney disease patients (37 %). Forty-two percent of RPV users accessed their results after their clinic appointments, 38 % prior to visiting the clinic. The majority of patients (76 %) had used the system to discuss treatment with their renal physician, while 20 % of patients gave permission to other members of their family to use RPV to monitor results on their behalf. Most users (78 %) reported accessing RPV on average 1-5 times/month. Most patients used RPV to monitor their kidney function, 81 % to check creatinine levels, 57 % to check potassium results. Ninety-two percent of patients found RPV easy to use and 93 % felt that overall the system helps them in taking care of their condition; 53 % of patients reported high satisfaction with RPV. Our results provide interesting insight into use of a system that gives patients web-based access to laboratory results. The fact that 20 % of patients delegate access to relatives also warrants further study. We propose that online access to laboratory results should be offered to all renal patients, although clinicians need to be mindful of the 'digital divide', i.e. part of the population that is not amenable to IT-based strategies for patient empowerment.

Enabling technologies for millimeter-wave radio-over-fiber systems in next generation heterogeneous mobile access networks

Science.gov (United States)

Zhang, Junwen; Yu, Jianjun; Wang, Jing; Xu, Mu; Cheng, Lin; Lu, Feng; Shen, Shuyi; Yan, Yan; Cho, Hyunwoo; Guidotti, Daniel; Chang, Gee-kung

2017-01-01

Fifth-generation (5G) wireless access network promises to support higher access data rate with more than 1,000 times capacity with respect to current long-term evolution (LTE) systems. New radio-access-technologies (RATs) based on higher carrier frequencies to millimeter-wave (MMW) radio-over-fiber, and carrier-aggregation (CA) using multi-band resources are intensively studied to support the high data rate access and effectively use of frequency resources in heterogeneous mobile network (Het-Net). In this paper, we investigate several enabling technologies for MMW RoF systems in 5G Het-Net. Efficient mobile fronthaul (MFH) solutions for 5G centralized radio access network (C-RAN) and beyond are proposed, analyzed and experimentally demonstrated based on the analog scheme. Digital predistortion based on memory polynomial for analog MFH linearization are presented with improved EVM performances and receiver sensitivity. We also propose and experimentally demonstrate a novel inter-/intra- RAT CA scheme for 5G Het- Net. The real-time standard 4G-LTE signal is carrier-aggregated with three broadband 60GHz MMW signals based on proposed optical-domain band-mapping method. RATs based on new waveforms have also been studied here to achieve higher spectral-efficiency (SE) in asynchronous environments. Full-duplex asynchronous quasi-gapless carrier aggregation scheme for MMW ROF inter-/intra-RAT based on the FBMC is also presented with 4G-LTE signals. Compared with OFDM-based signals with large guard-bands, FBMC achieves higher spectral-efficiency with better EVM performance at less received power and smaller guard-bands.

A satellite mobile communication system based on Band-Limited Quasi-Synchronous Code Division Multiple Access (BLQS-CDMA)

Science.gov (United States)

Degaudenzi, R.; Elia, C.; Viola, R.

1990-01-01

Discussed here is a new approach to code division multiple access applied to a mobile system for voice (and data) services based on Band Limited Quasi Synchronous Code Division Multiple Access (BLQS-CDMA). The system requires users to be chip synchronized to reduce the contribution of self-interference and to make use of voice activation in order to increase the satellite power efficiency. In order to achieve spectral efficiency, Nyquist chip pulse shaping is used with no detection performance impairment. The synchronization problems are solved in the forward link by distributing a master code, whereas carrier forced activation and closed loop control techniques have been adopted in the return link. System performance sensitivity to nonlinear amplification and timing/frequency synchronization errors are analyzed.

J-TEXT WebScope: An efficient data access and visualization system for long pulse fusion experiment

Energy Technology Data Exchange (ETDEWEB)

Zheng, Wei, E-mail: zhenghaku@gmail.com [State Key Laboratory of Advanced Electromagnetic Engineering and Technology in Huazhong University of Science and Technology, Wuhan 430074 (China); School of Electrical and Electronic Engineering in Huazhong University of Science and Technology, Wuhan 430074 (China); Wan, Kuanhong; Chen, Zhi; Hu, Feiran; Liu, Qiang [State Key Laboratory of Advanced Electromagnetic Engineering and Technology in Huazhong University of Science and Technology, Wuhan 430074 (China); School of Electrical and Electronic Engineering in Huazhong University of Science and Technology, Wuhan 430074 (China)

2016-11-15

Highlights: • No matter how large the data is, the response time is always less than 500 milliseconds. • It is intelligent and just gives you the data you want. • It can be accessed directly over the Internet without installing special client software if you already have a browser. • Adopt scale and segment technology to organize data. • To support a new database for the WebScope is quite easy. • With the configuration stored in user’s profile, you have your own portable WebScope. - Abstract: Fusion research is an international collaboration work. To enable researchers across the world to visualize and analyze the experiment data, a web based data access and visualization tool is quite important [1]. Now, a new WebScope based on RIA (Rich Internet Application) is designed and implemented to meet these requirements. On the browser side, a fluent and intuitive interface is provided for researchers at J-TEXT laboratory and collaborators from all over the world to view experiment data and related metadata. The fusion experiments will feature long pulse and high sampling rate in the future. The data access and visualization system in this work has adopted segment and scale concept. Large data samples are re-sampled in different scales and then split into segments for instant response. It allows users to view extremely large data on the web browser efficiently, without worrying about the limitation on the size of the data. The HTML5 and JavaScript based web front-end can provide intuitive and fluent user experience. On the server side, a RESTful (Representational State Transfer) web API, which is based on ASP.NET MVC (Model View Controller), allows users to access the data and its metadata through HTTP (HyperText Transfer Protocol). An interface to the database has been designed to decouple the data access and visualization system from the data storage. It can be applied upon any data storage system like MDSplus or JTEXTDB, and this system is very easy to

J-TEXT WebScope: An efficient data access and visualization system for long pulse fusion experiment

International Nuclear Information System (INIS)

Zheng, Wei; Wan, Kuanhong; Chen, Zhi; Hu, Feiran; Liu, Qiang

2016-01-01

Highlights: • No matter how large the data is, the response time is always less than 500 milliseconds. • It is intelligent and just gives you the data you want. • It can be accessed directly over the Internet without installing special client software if you already have a browser. • Adopt scale and segment technology to organize data. • To support a new database for the WebScope is quite easy. • With the configuration stored in user’s profile, you have your own portable WebScope. - Abstract: Fusion research is an international collaboration work. To enable researchers across the world to visualize and analyze the experiment data, a web based data access and visualization tool is quite important [1]. Now, a new WebScope based on RIA (Rich Internet Application) is designed and implemented to meet these requirements. On the browser side, a fluent and intuitive interface is provided for researchers at J-TEXT laboratory and collaborators from all over the world to view experiment data and related metadata. The fusion experiments will feature long pulse and high sampling rate in the future. The data access and visualization system in this work has adopted segment and scale concept. Large data samples are re-sampled in different scales and then split into segments for instant response. It allows users to view extremely large data on the web browser efficiently, without worrying about the limitation on the size of the data. The HTML5 and JavaScript based web front-end can provide intuitive and fluent user experience. On the server side, a RESTful (Representational State Transfer) web API, which is based on ASP.NET MVC (Model View Controller), allows users to access the data and its metadata through HTTP (HyperText Transfer Protocol). An interface to the database has been designed to decouple the data access and visualization system from the data storage. It can be applied upon any data storage system like MDSplus or JTEXTDB, and this system is very easy to

Study on Mandatory Access Control in a Secure Database Management System

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

This paper proposes a security policy model for mandatory access control in class B1 database management system whose level of labeling is tuple. The relation-hierarchical data model is extended to multilevel relation-hierarchical data model. Based on the multilevel relation-hierarchical data model, the concept of upper-lower layer relational integrity is presented after we analyze and eliminate the covert channels caused by the database integrity. Two SQL statements are extended to process polyinstantiation in the multilevel secure environment. The system is based on the multilevel relation-hierarchical data model and is capable of integratively storing and manipulating multilevel complicated objects (e. g., multilevel spatial data) and multilevel conventional data ( e. g., integer. real number and character string).

Incident and Trafficking Database: New Systems for Reporting and Accessing State Information

International Nuclear Information System (INIS)

Dimitrovski, D.; Kittley, S.

2015-01-01

The IAEA's Incident and Trafficking Database (ITDB) is the Agency's authoritative source for information on incidents in which nuclear and other radioactive material is out of national regulatory control. It was established in 1995 and, as of June 2014, 126 States participate in the ITDB programme. Currently, the database contains over 2500 confirmed incidents, out of which 21% involve nuclear material, 62% radioactive source and 17% radioactively contaminated material. In recent years, the system for States to report incidents to the ITDB has been evolving — moving from fax-based to secure email and most recently to secure on-line reporting. A Beta version of the on-line system was rolled out this June, offering a simple, yet secure, communication channel for member states to provide information. In addition the system serves as a central hub for information related to official communication of the IAEA with Member States so some communication that is traditionally shared by e-mail does not get lost when ITDB counterparts change. In addition the new reporting system incorporates optional features that allow multiple Member State users to collaboratively contribute toward an INF. States are also being given secure on-line access to a streamlined version of the ITDB. This improves States' capabilities to retrieve and analyze information for their own purposes. In addition, on-line access to ITDB statistical information on incidents is available to States through an ITDB Dashboard. The dashboard contains aggregate information on number and types of incidents, material involved, as well some other statistics related to the ITDB that is typically provided in the ITDB Quarterly reports. (author)

Mobile and Accessible Learning for MOOCs

Science.gov (United States)

Sharples, Mike; Kloos, Carlos Delgado; Dimitriadis, Yannis; Garlatti, Serge; Specht, Marcus

2015-01-01

Many modern web-based systems provide a "responsive" design that allows material and services to be accessed on mobile and desktop devices, with the aim of providing "ubiquitous access." Besides offering access to learning materials such as podcasts and videos across multiple locations, mobile, wearable and ubiquitous…

User-Based Information Retrieval System Interface Evaluation: An Examination of an On-Line Public Access Catalog.

Science.gov (United States)

Hert, Carol A.; Nilan, Michael S.

1991-01-01

Presents preliminary data that characterizes the relationship between what users say they are trying to accomplish when using an online public access catalog (OPAC) and their perceptions of what input to give the system. Human-machine interaction is discussed, and appropriate methods for evaluating information retrieval systems are considered. (18…

Open Access Publishing in Particle Physics

CERN Document Server

2007-01-01

Particle Physics, often referred to as High Energy Physics (HEP), spearheaded the Open Access dissemination of scientific results with the mass mailing of preprints in the pre-Web era and with the launch of the arXiv preprint system at the dawn of the '90s. The HEP community is now ready for a further push to Open Access while retaining all the advantages of the peerreview system and, at the same time, bring the spiralling cost of journal subscriptions under control. I will present a plan for the conversion to Open Access of HEP peer-reviewed journals, through a consortium of HEP funding agencies, laboratories and libraries: SCOAP3 (Sponsoring Consortium for Open Access Publishing in Particle Physics). SCOAP3 will engage with scientific publishers towards building a sustainable model for Open Access publishing, which is as transparent as possible for HEP authors. The current system in which journals income comes from subscription fees is replaced with a scheme where SCOAP3 compensates publishers for the costs...

An Automated Mouse Tail Vascular Access System by Vision and Pressure Feedback.

Science.gov (United States)

Chang, Yen-Chi; Berry-Pusey, Brittany; Yasin, Rashid; Vu, Nam; Maraglia, Brandon; Chatziioannou, Arion X; Tsao, Tsu-Chin

2015-08-01

This paper develops an automated vascular access system (A-VAS) with novel vision-based vein and needle detection methods and real-time pressure feedback for murine drug delivery. Mouse tail vein injection is a routine but critical step for preclinical imaging applications. Due to the small vein diameter and external disturbances such as tail hair, pigmentation, and scales, identifying vein location is difficult and manual injections usually result in poor repeatability. To improve the injection accuracy, consistency, safety, and processing time, A-VAS was developed to overcome difficulties in vein detection noise rejection, robustness in needle tracking, and visual servoing integration with the mechatronics system.

Architectural Considerations of Fiber-Radio Millimeter-Wave Wireless Access Systems

Science.gov (United States)

Kitayama, Ken-Ichi

The architecture of fiber-radio mm-wave wireless access systems critically depends upon the optical mm-wave generation and transport techniques. Four optical mm-wave generation and transport techniques: 1) optical self-heterodyning, 2) external modulation, 3) up- and downconversion, and 4) optical transceiver, will be assessed. From the technical viewpoints, their advantages and disadvantages are discussed. The economical assessment, focusing on the cost of a base station BS ( ), will suggest that the optical transceiver looks the most promising in the long run, but in the near future, however, the external modulation will be cost-effective. The experimental results of 60 GHz testbeds using the external modulation will support the conclusion.

Atomic memory access hardware implementations

Science.gov (United States)

Ahn, Jung Ho; Erez, Mattan; Dally, William J

2015-02-17

Atomic memory access requests are handled using a variety of systems and methods. According to one example method, a data-processing circuit having an address-request generator that issues requests to a common memory implements a method of processing the requests using a memory-access intervention circuit coupled between the generator and the common memory. The method identifies a current atomic-memory access request from a plurality of memory access requests. A data set is stored that corresponds to the current atomic-memory access request in a data storage circuit within the intervention circuit. It is determined whether the current atomic-memory access request corresponds to at least one previously-stored atomic-memory access request. In response to determining correspondence, the current request is implemented by retrieving data from the common memory. The data is modified in response to the current request and at least one other access request in the memory-access intervention circuit.

Computational experiment for the purpose of determining the probabilistic and temporal characteristics of information security systems against unauthorized access in automated information systems

Directory of Open Access Journals (Sweden)

A. V. Skrypnikov

2017-01-01

Full Text Available The article is devoted to the method of experimental estimation of parameters of functioning of standard information protection systems from unauthorized access, certified, widely used in organizations operating automated information systems. In the course of the experiment, statistical data were evaluated in the dynamics of the functioning of information security systems against unauthorized access in automated information systems. Registration of the parameters for the execution time of protective protection functions was carried out using a special utility called ProcessMonitor from the Sysinternals suite of utilities used to filter processes and threads. The loading of the processor and main memory of the computer with the use of special software, specially designed for performing experimental research, simulates the operation of GIS in real-world work for its intended purpose. A special software for simulating the work of a system with high load is developed in "VisualStudio 2015" within the framework of "ConsoleApplication". At the same time, the processor is loaded at a level of 50-70% and 60-80% of the operative memory. The obtained values of the time of implementation of protective functions in conditions of high utilization of resources of computer facilities for their intended purpose will allow us to assess the conflict and dynamic properties of the GIS. In the future, the obtained experimental estimates can be used to develop a model of information security in automated information systems, as well as in the formation of quality requirements (resource intensity, response time to the user's request, availability, etc.. Also, the results of the computational experiment in the future can be used to develop a software package for assessing the dynamic performance of information security systems against unauthorized access in automated information systems

Digital predistortion of 75–110 GHz W-band frequency multiplier for fiber wireless short range access systems

DEFF Research Database (Denmark)

Zhao, Ying; Deng, Lei; Pang, Xiaodan

2011-01-01

be effectively pre-compensated. Without using costly W-band components, a transmission system with 26km fiber and 4m wireless transmission operating at 99.6GHz is experimentally validated. Adjacent-channel power ratio (ACPR) improvements for IQ-modulated vector signals are guaranteed and transmission......We present a W-band fiber-wireless transmission system based on a nonlinear frequency multiplier for high-speed wireless short range access applications. By implementing a baseband digital signal predistortion scheme, intensive nonlinear distortions induced in a sextuple frequency multiplier can...... performances for fiber and wireless channels are studied. This W-band predistortion technique is a promising candidate for applications in high capacity wireless-fiber access systems....

Endoscopic Ultrasonography-Guided Techniques for Accessing and Draining the Biliary System and the Pancreatic Duct.

Science.gov (United States)

Rimbaş, Mihai; Larghi, Alberto

2017-10-01

When endoscopic retrograde cholangiopancreatography (ERCP) fails to decompress the biliary system or the pancreatic duct, endoscopic ultrasonography (EUS)-guided biliary or pancreatic access and drainage can be used. Data show a high success rate and acceptable adverse event rate for EUS-guided biliary drainage. The outcomes of EUS-guided biliary drainage seem equivalent to percutaneous drainage and ERCP, whereas only retrospective studies are available for pancreatic duct drainage. In this article, revision of the technical and clinical status and the current evidence of interventional EUS-guided biliary and pancreatic duct access and drainage are presented. Copyright © 2017 Elsevier Inc. All rights reserved.

Time dependent policy-based access control

DEFF Research Database (Denmark)

Vasilikos, Panagiotis; Nielson, Flemming; Nielson, Hanne Riis

2017-01-01

also on other attributes of the environment such as the time. In this paper, we use systems of Timed Automata to model distributed systems and we present a logic in which one can express time-dependent policies for access control. We show how a fragment of our logic can be reduced to a logic......Access control policies are essential to determine who is allowed to access data in a system without compromising the data's security. However, applications inside a distributed environment may require those policies to be dependent on the actual content of the data, the flow of information, while...... that current model checkers for Timed Automata such as UPPAAL can handle and we present a translator that performs this reduction. We then use our translator and UPPAAL to enforce time-dependent policy-based access control on an example application from the aerospace industry....

The Mission Accessibility of Near-Earth Asteroids

Science.gov (United States)

Barbee, Brent W.; Abell, P. A.; Adamo, D. R.; Mazanek, D. D.; Johnson, L. N.; Yeomans, D. K.; Chodas, P. W.; Chamberlin, A. B.; Benner, L. A. M.; Taylor, P.;

Research on the Legal Regulation of Market Access for Agricultural Products in China

Institute of Scientific and Technical Information of China (English)

2011-01-01

On the basis of defining the concept of market access for agricultural products,this paper analyzes the necessity of establishing market access system of agricultural products,proposes the conception of establishing market access system of agricultural products in China;sets up the frame of market access system of agricultural products;analyzes the rationality of the frame of market access system of agricultural products;poses the consideration of economic law regarding setup of market access system of agricultural products.This paper also puts forward the legislative suggestions for establishing market access system of agricultural products as follows:establish the frame of market access system of agricultural products taking quality access as core;establish and perfect the compensation and relief system of guaranteeing benefit of manager and producers;establish the market access system of agricultural products with hierarchical structure;sort out existing laws and form the sound the legal frame of market access system of agricultural products.

Title III Evaluation Report for the Access Road System

International Nuclear Information System (INIS)

H.R. Montalvo

1998-01-01

The objective of this evaluation is to provide recommendations to ensure consistency between the technical baseline requirements, baseline design, and the as-constructed Access Roads. Recommendations for resolving discrepancies between the as-constructed system, the technical baseline requirements, and the baseline design are included in this report. Cost and Schedule estimates are provided for all recommended modifications. This report does not address items which do not meet current safety or code requirements. These items are identified to the CMO and immediate action is taken to correct the situation. The report does identify safety and code items for which the A/E is recommending improvements. The recommended improvements will exceed the minimum requirements of applicable code and safety guide lines. These recommendations are intended to improve and enhance the operation and maintenance of the facility

Novel secure and bandwidth efficient optical code division multiplexed system for future access networks

Science.gov (United States)

Singh, Simranjit

2016-12-01

In this paper, a spectrally coded optical code division multiple access (OCDMA) system using a hybrid modulation scheme has been investigated. The idea is to propose an effective approach for simultaneous improvement of the system capacity and security. Data formats, NRZ (non-return to zero), DQPSK (differential quadrature phase shift keying), and PoISk (polarisation shift keying) are used to get the orthogonal modulated signal. It is observed that the proposed hybrid modulation provides efficient utilisation of bandwidth, increases the data capacity and enhances the data confidentiality over existing OCDMA systems. Further, the proposed system performance is compared with the current state-of-the-art OCDMA schemes.

Rotated Walsh-Hadamard Spreading with Robust Channel Estimation for a Coded MC-CDMA System

Directory of Open Access Journals (Sweden)

Raulefs Ronald

2004-01-01

Full Text Available We investigate rotated Walsh-Hadamard spreading matrices for a broadband MC-CDMA system with robust channel estimation in the synchronous downlink. The similarities between rotated spreading and signal space diversity are outlined. In a multiuser MC-CDMA system, possible performance improvements are based on the chosen detector, the channel code, and its Hamming distance. By applying rotated spreading in comparison to a standard Walsh-Hadamard spreading code, a higher throughput can be achieved. As combining the channel code and the spreading code forms a concatenated code, the overall minimum Hamming distance of the concatenated code increases. This asymptotically results in an improvement of the bit error rate for high signal-to-noise ratio. Higher convolutional channel code rates are mostly generated by puncturing good low-rate channel codes. The overall Hamming distance decreases significantly for the punctured channel codes. Higher channel code rates are favorable for MC-CDMA, as MC-CDMA utilizes diversity more efficiently compared to pure OFDMA. The application of rotated spreading in an MC-CDMA system allows exploiting diversity even further. We demonstrate that the rotated spreading gain is still present for a robust pilot-aided channel estimator. In a well-designed system, rotated spreading extends the performance by using a maximum likelihood detector with robust channel estimation at the receiver by about 1 dB.

PHOTO ENCODING OF ANALOG WATER METER FOR USER ACCESS AND PAYMENT SYSTEM

OpenAIRE

GODFREY A. MILLS; MOSES A. ACQUAH; APPAH BREMANG

2012-01-01

This paper presents design reconfiguration of analog water meter to provide remote access to user water consumption and billing records, payments, and meter device monitoring using photo-encoding as the detecting method for water consumption, a PIC18F2423 microcontroller for data processing, and SMS (short message service) technology for data transportation. To validate the system design, an analog water meter was converted into a digital equivalent and interfaced to the cellular network to t...

Essential Medicines in Nigeria: Foregrounding Access to Affordable ...

African Journals Online (AJOL)

Abstract. Within every functional healthcare system, access to quality and affordable essential medicine stands out as one of the building blocks. However ... Keywords: Access to medicines, Essential medicines, Healthcare, Public health facilities, Counterfeit medicines, Traditional medicines, Health systems, Systems theory ...

Fine-Grained Access Control for Electronic Health Record Systems

Science.gov (United States)

Hue, Pham Thi Bach; Wohlgemuth, Sven; Echizen, Isao; Thuy, Dong Thi Bich; Thuc, Nguyen Dinh

There needs to be a strategy for securing the privacy of patients when exchanging health records between various entities over the Internet. Despite the fact that health care providers such as Google Health and Microsoft Corp.'s Health Vault comply with the U.S Health Insurance Portability and Accountability Act (HIPAA), the privacy of patients is still at risk. Several encryption schemes and access control mechanisms have been suggested to protect the disclosure of a patient's health record especially from unauthorized entities. However, by implementing these approaches, data owners are not capable of controlling and protecting the disclosure of the individual sensitive attributes of their health records. This raises the need to adopt a secure mechanism to protect personal information against unauthorized disclosure. Therefore, we propose a new Fine-grained Access Control (FGAC) mechanism that is based on subkeys, which would allow a data owner to further control the access to his data at the column-level. We also propose a new mechanism to efficiently reduce the number of keys maintained by a data owner in cases when the users have different access privileges to different columns of the data being shared.

45 CFR 310.40 - What requirements apply for accessing systems and records for monitoring Computerized Tribal IV-D...

Science.gov (United States)

2010-10-01

... 45 Public Welfare 2 2010-10-01 2010-10-01 false What requirements apply for accessing systems and records for monitoring Computerized Tribal IV-D Systems and Office Automation? 310.40 Section 310.40... COMPUTERIZED TRIBAL IV-D SYSTEMS AND OFFICE AUTOMATION Accountability and Monitoring Procedures for...

Access Rights Distribution

Directory of Open Access Journals (Sweden)

T. M. Pestunova

2011-03-01

Full Text Available The main aspects of the development of the information system, which grants users the rights for access to automated information system resources on the basis of the organization business-processes, are considered. The conceptual, informational, functional models of the system, as well as a model, which allows to realize control while using various formal models (RBAC, DAC, MAC, are described.

Request Stream Control for the Access to Broadband Multimedia Educational Resources in the Distance Learning System

Directory of Open Access Journals (Sweden)

Irina Pavlovna Bolodurina

2013-10-01

Full Text Available This article presents a model of queuing system for broadband multimedia educational resources, as well as a model of access to a hybrid cloud system storage. These models are used to enhance the efficiency of computing resources in a distance learning system. An additional OpenStack control module has been developed to achieve the distribution of request streams and balance the load between cloud nodes.

METHOD AND ABSTRACT MODEL FOR CONTROL AND ACCESS RIGHTS BY REQUESTS REDIRECTION

Directory of Open Access Journals (Sweden)

K. A. Shcheglov

2015-11-01

Full Text Available We have researched implementation problems of control and access rights of subjects to objects in modern computer systems. We have suggested access control method based on objects access requests redirection. The method possesses a distinctive feature as compared to discretional access control. In case when a subject needs to deny writing (object modification, it is not denied but redirected (access rights are not changed, but operation is performed with another object. This gives the possibility to implement access policies to system objects without breaking the system and applications operability, and share correctly access objects between subjects. This important property of suggested access control method enables to solve fundamentally new system objects securing problems like system resources virtualization aimed to protect system objects from users’ and applications attacks. We have created an abstract model, and it shows that this method (access control from subjects to objects based on requests redirection can be used as self-sufficient access control method, implementing any access control policy (from subjects to objects, thus being an alternative to discretional access control method.

Gaining Access.

Science.gov (United States)

Wand, Sean; Thermos, Adam C.

1998-01-01

Explains the issues to consider before a college decides to purchase a card-access system. The benefits of automation, questions involving implementation, the criteria for technology selection, what typical card technology involves, privacy concerns, and the placement of card readers are discussed. (GR)

Transmission access issues: Present and future

International Nuclear Information System (INIS)

Bahl, P.K.; Gray, R.G.

1992-01-01

In recent years, the electric industry has undergone dramatic changes as the federal and state governments have encouraged bulk power production by Independent Power Producers (IPPS) and Qualified Facilities (QFs). With decentralization and the consequent competition in the field of bulk power production, there has emerged the problem of non-utility generators (NUGS) and of transmission dependent utilities accessing the existing transmission systems owned by electric utilities. This paper presents current and future issues related to transmission access by IPPS, QFs and transmission dependent utilities. These issues include: (a) impact on system reliability, (b) impact of pricing strategies, (c) changes in state and federal regulations, (d) transmission proposals by various entities, (e) present access arrangements, (f) formation of the Western Systems Power Pool (WSPP), and (g) siting difficulties. The transmission access problem warrants consideration of transmission services, coordination among electric utilities, joint planning on a regional basis, and accommodation of IPPs and NUGs

Effective use of multibeam antenna and space-time multiple access technology in modern mobile communication systems

OpenAIRE

Moskalets, N. V.

2015-01-01

A possibility for efficient use of radio-frequency spectrum and of corresponding increase in productivity of mobile communication system with space-time multiple access obtained by use of multibeam antenna of base station is considered.

The FODA-TDMA satellite access scheme - Presentation, study of the system, and results

Science.gov (United States)

Celandroni, Nedo; Ferro, Erina

1991-12-01

A description is given of FODA-TDMA, a satellite access scheme designed for mixed traffic. The study of the system is presented and the choice of some parameters is justified. A simplified analytic solution is found, describing the steady-state behavior of the system. Some results of the simulation tests for an already existing hardware environment are also presented for the channel speeds of 2 and 8 Mb/s, considering both the stationary and the transient cases. The results of the experimentation at 2 Mb/s on the satellite Eutelsat-F2 are also presented and compared with the results of the simulation.

Access to the city

DEFF Research Database (Denmark)

Andreasen, Manja Hoppe; Møller-Jensen, Lasse

2017-01-01

This paper is concerned with access to the city for urban residents living in the periphery of Dar es Salaam, Tanzania. The paper presents an analysis of the mobility practices of residents and investigates the mobility constraints they experience in relation to the limited accessibility provided...... mobility and access to the city for residents in the periphery. Regular mobility is an ingrained part of residents' livelihood strategies. The majority of households rely on one or more members regularly travelling to central parts of the city in relation to their livelihood activities. The analysis...... by road and traffic conditions and highlights how accessibility problems of peripheral settlements are not easily understood separately from the general dysfunctions of the overall mobility system of city....

Combining sync&share functionality with filesystem-like access

CERN Multimedia

CERN. Geneva

2014-01-01

In our presentation we will analyse approaches to combine the sync & share functionality with file system-like access to data. While relatively small data volumes (GBs) can be distributed by sync&share application across user devices such as PCs, laptops and mobiles, interacting with really large data volumes (TBs, PBs) may require additional remote data access mechanism such as filesystem-like interface. We will discuss several ways for offering filesystem-like access in addition to sync & share functionality. Todays sync & share solutions may employ various data organisation in the back-end including local and distributed file systems and object stores. Therefore various approaches to providing the client with filesystem-like access are necessary in these systems. We will present possible options to integrate the filesystem-like access with sync&share functionality in the popular sync&share system. We will also show a NDS2 project solution where data backups and archives are kept sec...

Real-time Measurements of an Optical Reconfigurable Radio Access Unit for 5G Wireless Access Networks

DEFF Research Database (Denmark)

Rodríguez, Sebastián; Morales Vicente, Alvaro; Rommel, Simon

2017-01-01

A reconfigurable radio access unit able to switch wavelength, RF carrier frequency and optical path is experimentally demonstrated. The system is able to do the switching processes correctly, while achieving BER values below FEC limit.......A reconfigurable radio access unit able to switch wavelength, RF carrier frequency and optical path is experimentally demonstrated. The system is able to do the switching processes correctly, while achieving BER values below FEC limit....

Insights into the government's role in food system policy making: improving access to healthy, local food alongside other priorities.

Science.gov (United States)

Wegener, Jessica; Raine, Kim D; Hanning, Rhona M

2012-11-12

Government actors have an important role to play in creating healthy public policies and supportive environments to facilitate access to safe, affordable, nutritious food. The purpose of this research was to examine Waterloo Region (Ontario, Canada) as a case study for "what works" with respect to facilitating access to healthy, local food through regional food system policy making. Policy and planning approaches were explored through multi-sectoral perspectives of: (a) the development and adoption of food policies as part of the comprehensive planning process; (b) barriers to food system planning; and (c) the role and motivation of the Region's public health and planning departments in food system policy making. Forty-seven in-depth interviews with decision makers, experts in public health and planning, and local food system stakeholders provided rich insight into strategic government actions, as well as the local and historical context within which food system policies were developed. Grounded theory methods were used to identify key overarching themes including: "strategic positioning", "partnerships" and "knowledge transfer" and related sub-themes ("aligned agendas", "issue framing", "visioning" and "legitimacy"). A conceptual framework to illustrate the process and features of food system policy making is presented and can be used as a starting point to  engage multi-sectoral stakeholders in plans and actions to facilitate access to healthy food.

Current status of the European contribution to the Remote Data Access System of the ITER Remote Experimentation Centre

International Nuclear Information System (INIS)

De Tommasi, G.; Manduchi, G.; Muir, D.G.; Ide, S.; Naito, O.; Urano, H.; Clement-Lorenzo, S.; Nakajima, N.; Ozeki, T.; Sartori, F.

2015-01-01

The ITER Remote Experimentation Centre (REC) is one of the projects under implementation within the BA agreement. The final objective of the REC is to allow researchers to take part in the experimentation on ITER from a remote location. Before ITER first operations, the REC will be used to evaluate ITER-relevant technologies for remote participation. Among the different software tools needed for remote participation, an important one is the Remote Data Access System (RDA), which provides a single software infrastructure to access data stored at the remotely participating experiment, regardless of the geographical location of the users. This paper introduces the European contribution to the RDA system for the REC.

A Conceptual Framework of Mapping Access to Health Care across EU Countries: The Patient Access Initiative.

Science.gov (United States)

Souliotis, Kyriakos; Hasardzhiev, Stanimir; Agapidaki, Eirini

Research evidence suggests that access to health care is the key influential factor for improved population health outcomes and health care system sustainability. Although the importance of addressing barriers in access to health care across European countries is well documented, little has been done to improve the situation. This is due to different definitions, approaches and policies, and partly due to persisting disparities in access within and between European countries. To bridge this gap, the Patient Access Partnership (PACT) developed (a) the '5As' definition of access, which details the five critical elements (adequacy, accessibility, affordability, appropriateness, and availability) of access to health care, (b) a multi-stakeholders' approach for mapping access, and (c) a 13-item questionnaire based on the 5As definition in an effort to address these obstacles and to identify best practices. These tools are expected to contribute effectively to addressing access barriers in practice, by suggesting a common framework and facilitating the exchange of knowledge and expertise, in order to improve access to health care between and within European countries. © 2016 S. Karger AG, Basel.