Heterogeneous wireless/wireline optical access networks with the R-EAT as backend component

NASA Astrophysics Data System (ADS)

Hagedorn, Klaus; Gindera, Ralf; Stohr, Andreas; Jager, Dieter

2004-09-01

A heterogeneous wireless/wireline optical transmission link using a reflection type electroabsorption transceiver (R-EAT) is presented. Simultaneous transmission of full-duplex broadband wireless LAN (WLAN) channels and 1Gb/s base band data is experimentally demonstrated. The system link employs sub-carrier multiplexing (SCM) and two optical channels for full duplex transmission of various analog WLAN channels and downlink digital base band data. The developed link architecture is suitable for simultaneous transmission of broadband wireline and wireless signals, it enables the coexistence and interoperability between wireline and wireless access technologies. The developed R-EAT component employed in this wireline/wireless access system, features "single-chip-component" base stations in access networks with star type topology where only a single optical fiber is used for bidirectional optical transmission. The R-EAT can be used within the optical C-band (1530- 1560nm) and is suitable for (D)WDM networks. Bit error rate measurements demonstrate the capabilities of the R-EAT for 1Gb/s base band transmission. The analog performance for WLAN transmission is characterised by a spurious free dynamic range (SFDR) of more than 75dB and 90dB for uplink and downlink transmission, respectively. The link gain for uplink and downlink transmission is -42dB and -37dB, respectively. The demonstrates the analog performances of the R-EAT for being used in wireless access networks such as W-LAN.

Exploring Processes and Outcomes of Wireless Internet in Higher Education: A Case Study of a University's Early Experience

ERIC Educational Resources Information Center

Lee, Lisa

2007-01-01

Many universities in the UK have recently started offering their staff and students free wireless Internet access through Wireless Local Area Network (WLAN) technologies, such as Wi-Fi. Based on a small empirical study of WLAN deployment in a university setting, the article explores adoption processes of the new technology by both the organisation…

Multi-Band Received Signal Strength Fingerprinting Based Indoor Location System

NASA Astrophysics Data System (ADS)

Sertthin, Chinnapat; Fujii, Takeo; Ohtsuki, Tomoaki; Nakagawa, Masao

This paper proposes a new multi-band received signal strength (MRSS) fingerprinting based indoor location system, which employs the frequency diversity on the conventional single-band received signal strength (RSS) fingerprinting based indoor location system. In the proposed system, the impacts of frequency diversity on the enhancements of positioning accuracy are analyzed. Effectiveness of the proposed system is proved by experimental approach, which was conducted in non line-of-sight (NLOS) environment under the area of 103m2 at Yagami Campus, Keio University. WLAN access points, which simultaneously transmit dual-band signal of 2.4 and 5.2GHz, are utilized as transmitters. Likewise, a dual-band WLAN receiver is utilized as a receiver. Signal distances calculated by both Manhattan and Euclidean were classified by K-Nearest Neighbor (KNN) classifier to illustrate the performance of the proposed system. The results confirmed that Frequency diversity attributions of multi-band signal provide accuracy improvement over 50% of the conventional single-band.

Design and Implementation of Secure Area Expansion Scheme for Public Wireless LAN Services

NASA Astrophysics Data System (ADS)

Watanabe, Ryu; Tanaka, Toshiaki

Recently, wireless LAN (WLAN) technology has become a major wireless communication method. The communication bandwidth is increasing and speeds have attained rates exceeding 100 Mbps. Therefore, WLAN technology is regarded as one of the promising communication methods for future networks. In addition, public WLAN connection services can be used in many locations. However, the number of the access points (AP) is insufficient for seamless communication and it cannot be said that users can use the service ubiquitously. An ad-hoc network style connection can be used to expand the coverage area of a public WLAN service. By relaying the user messages among the user nodes, a node can obtain an Internet connection via an AP, even though the node is located outside the AP's direct wireless connection area. Such a coverage area extending technology has many advantages thanks to the feature that no additional infrastructure is required. Therefore, there is a strong demand for this technology as it allows the cost-effective construction of future networks. When a secure ad-hoc routing protocol is used for message exchange in the WLAN service, the message routes are protected from malicious behavior such as route forging and can be maintained appropriately. To do this, however, a new node that wants to join the WLAN service has to obtain information such as the public key certificate and IP address in order to start secure ad-hoc routing. In other words, an initial setup is required for every network node to join the WLAN service properly. Ordinarily, such information should be assigned from the AP. However, new nodes cannot always contact an AP directly. Therefore, there are problems about information delivery in the initial setup of a network node. These problems originate in the multi hop connection based on the ad-hoc routing protocols. In order to realize an expanded area WLAN service, in this paper, the authors propose a secure public key certificate and address provision scheme during the initial setup phase on mobile nodes for the service. The proposed scheme also considers the protection of user privacy. Accordingly, none of the user nodes has to reveal their unique and persistent information to other nodes. Instead of using such information, temporary values are sent by an AP to mobile nodes and used for secure ad-hoc routing operations. Therefore, our proposed scheme prevents tracking by malicious parties by avoiding the use of unique information. Moreover, a test bed was also implemented based on the proposal and an evaluation was carried out in order to confirm performance. In addition, the authors describe a countermeasure against denial of service (DoS) attacks based on the approach to privacy protection described in our proposal.

Modeling and Analysis of Hybrid Cellular/WLAN Systems with Integrated Service-Based Vertical Handoff Schemes

NASA Astrophysics Data System (ADS)

Xia, Weiwei; Shen, Lianfeng

We propose two vertical handoff schemes for cellular network and wireless local area network (WLAN) integration: integrated service-based handoff (ISH) and integrated service-based handoff with queue capabilities (ISHQ). Compared with existing handoff schemes in integrated cellular/WLAN networks, the proposed schemes consider a more comprehensive set of system characteristics such as different features of voice and data services, dynamic information about the admitted calls, user mobility and vertical handoffs in two directions. The code division multiple access (CDMA) cellular network and IEEE 802.11e WLAN are taken into account in the proposed schemes. We model the integrated networks by using multi-dimensional Markov chains and the major performance measures are derived for voice and data services. The important system parameters such as thresholds to prioritize handoff voice calls and queue sizes are optimized. Numerical results demonstrate that the proposed ISHQ scheme can maximize the utilization of overall bandwidth resources with the best quality of service (QoS) provisioning for voice and data services.

A wireless PDA-based physiological monitoring system for patient transport.

PubMed

Lin, Yuan-Hsiang; Jan, I-Chien; Ko, Patrick Chow-In; Chen, Yen-Yu; Wong, Jau-Min; Jan, Gwo-Jen

2004-12-01

This paper proposes a mobile patient monitoring system, which integrates current personal digital assistant (PDA) technology and wireless local area network (WLAN) technology. At the patient's location, a wireless PDA-based monitor is used to acquire continuously the patient's vital signs, including heart rate, three-lead electrocardiography, and SpO2. Through the WLAN, the patient's biosignals can be transmitted in real-time to a remote central management unit, and authorized medical staffs can access the data and the case history of the patient, either by the central management unit or the wireless devices. A prototype of this system has been developed and implemented. The system has been evaluated by technical verification, clinical test, and user survey. The evaluation of performance yields a high degree of satisfaction (mean = 4.64, standard deviation--SD = 0.53 in a five-point Likert scale) of users who used the PDA-based system for intrahospital transport. The results also show that the wireless PDA model is superior to the currently used monitors both in mobility and in usability, and is, therefore, better suited to patient transport.

Measurements of the Received Signal Level and Service Coverage Area at the IEEE 802.11 Access Point in the Building

NASA Astrophysics Data System (ADS)

Gunantara, N.; Sudiarta, P. K.; Prasetya, AAN A. I.; Dharma, A.; Gde Antara, I. N.

2018-04-01

Access point (AP) is part of a Wireless Local Access Network (WLAN) with its communications using WiFi. AP is used to transmit and receive data to users/clients. The ability of AP to serve users/clients depends on many factors. Moreover, if AP is applied in conditions inside the building. In this study, AP is installed at two points inside the building and then measured in the form of the received signal level (RSL) and service coverage area. One AP measured its performance by 26 measurement points and the other AP measured its performance by 20 measurement points. When AP has measured its performance then another AP position is switched off. Based on the measurement result, the received signal level value is the highest value is about -47 dBm at a distance of 3.2 m, while the lowest is about -79 dBm at a 9.21 m because it is on barrier 2 walls. While based on service coverage area, the area which is far away from the AP then the quality of service becomes bad because the transmitted signal is weakening caused by the distance and the loss of the wall.

Wireless local area network security.

PubMed

Bergeron, Bryan P

2004-01-01

Wireless local area networks (WLANs) are increasingly popular in clinical settings because they facilitate the use of wireless PDAs, laptops, and other pervasive computing devices at the point of care. However, because of the relative immaturity of wireless network technology and evolving standards, WLANs, if improperly configured, can present significant security risks. Understanding the security limitations of the technology and available fixes can help minimize the risks of clinical data loss and maintain compliance with HIPAA guidelines.

WLANs for the 21st Century Library

ERIC Educational Resources Information Center

Calamari, Cal

2009-01-01

As educational and research needs have changed, libraries have changed as well. They must meet ever-increasing demand for access to online media, subscriptions to archives, video, audio, and other content. The way a user/patron accesses this information has also changed. Gone are the days of a few hardwired desktops or computer carts. While…

ASSESSMENT OF PUBLIC EXPOSURE FORM WLANS IN THE WEST BANK-PALESTINE.

PubMed

Lahham, Adnan; Sharabati, Afifeh; ALMasri, Hussein

2017-11-01

A total of 271 measurements were conducted at 69 different sites including homes, hospitals, educational institutions and other public places to assess the exposure to radiofrequency emission from wireless local area networks (WLANs). Measurements were conducted at different distances from 40 to 10 m from the access points (APs) in real life conditions using Narda SRM-3000 selective radiation meter. Three measurements modes were considered at 1 m distance from the AP which are transmit mode, idle mode, and from the client card (laptop computer). All measurements were conducted indoor in the West Bank environment. Power density levels from WLAN systems were found to vary from 0.001 to ~1.9 μW cm-2 with an average of 0.12 μW cm-2. Maximum value found was in university environment, while the minimum was found in schools. For one measurement case where the AP was 20 cm far while transmitting large files, the measured power density reached a value of ~4.5 μW cm-2. This value is however 221 times below the general public exposure limit recommended by the International Commission on Non-Ionizing Radiation Protection, which was not exceeded in any case. Measurements of power density at 1 m around the laptop resulted in less exposure than the AP in both transmit and idle modes as well. Specific absorption rate for the head of the laptop user was estimated and found to vary from 0.1 to 2 mW/kg. The frequency distribution of measured power densities follows a log-normal distribution which is generally typical in the assessment of exposure resulting from sources of radiofrequency emissions. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Personal radiofrequency electromagnetic field exposure measurements in Swiss adolescents.

PubMed

Roser, Katharina; Schoeni, Anna; Struchen, Benjamin; Zahner, Marco; Eeftens, Marloes; Fröhlich, Jürg; Röösli, Martin

2017-02-01

Adolescents belong to the heaviest users of wireless communication devices, but little is known about their personal exposure to radiofrequency electromagnetic fields (RF-EMF). The aim of this paper is to describe personal RF-EMF exposure of Swiss adolescents and evaluate exposure relevant factors. Furthermore, personal measurements were used to estimate average contributions of various sources to the total absorbed RF-EMF dose of the brain and the whole body. Personal exposure was measured using a portable RF-EMF measurement device (ExpoM-RF) measuring 13 frequency bands ranging from 470 to 3600MHz. The participants carried the device for three consecutive days and kept a time-activity diary. In total, 90 adolescents aged 13 to 17years participated in the study conducted between May 2013 and April 2014. In addition, personal measurement values were combined with dose calculations for the use of wireless communication devices to quantify the contribution of various RF-EMF sources to the daily RF-EMF dose of adolescents. Main contributors to the total personal RF-EMF measurements of 63.2μW/m 2 (0.15V/m) were exposures from mobile phones (67.2%) and from mobile phone base stations (19.8%). WLAN at school and at home had little impact on the personal measurements (WLAN accounted for 3.5% of total personal measurements). According to the dose calculations, exposure from environmental sources (broadcast transmitters, mobile phone base stations, cordless phone base stations, WLAN access points, and mobile phones in the surroundings) contributed on average 6.0% to the brain dose and 9.0% to the whole-body dose. RF-EMF exposure of adolescents is dominated by their own mobile phone use. Environmental sources such as mobile phone base stations play a minor role. Copyright © 2016 Elsevier Ltd. All rights reserved.

Design of band-notched antenna with DG-CEBG

NASA Astrophysics Data System (ADS)

Jaglan, Naveen; Kanaujia, Binod Kumar; Gupta, Samir Dev; Srivastava, Shweta

2018-01-01

Ultra-wideband (UWB) disc monopole antenna with crescent shaped slot for double band-notched features is presented. Planned antenna discards worldwide interoperability for microwave access (WiMAX) band (3.3-3.6 GHz) and wireless local area network (WLAN) band (5-6 GHz). Defected ground compact electromagnetic band gap (DG-CEBG) designs are used to accomplish band notches in WiMAX and WLAN bands. Defected ground planes are utilised to achieve compactness in electromagnetic band gap (EBG) structures. The proposed WiMAX and WLAN DG-CEBG designs show a compactness of around 46% and 50%, respectively, over mushroom EBG structures. Parametric analyses of DG-CEBG design factors are carried out to control the notched frequencies. Stepwise notch transition from upper to lower frequencies is presented with incremental inductance augmentation. The proposed antenna is made-up on low-cost FR-4 substrate of complete extents as (42 × 50 × 1.6) mm3.Fabricated sample antenna shows excellent consistency in simulated and measured outcomes.

A highly linear power amplifier for WLAN

NASA Astrophysics Data System (ADS)

Jie, Jin; Jia, Shi; Baoli, Ai; Xuguang, Zhang

2016-02-01

A three-stage power amplifier (PA) for WLAN application in 2.4-2.5 GHz is presented. The proposed PA employs an adaptive bias circuit to adjust the operating point of the PA to improve the linearity of the PA. Two methods to short the 2nd harmonic circuit are compared in the area of efficiency and gain of the PA. The PA is taped out in the process of 2 μm InGaP/GaAs HBT and is tested by the evaluation board. The measured results show that 31.5 dB power gain and 29.3 dBm P1dB with an associated 40.4% power added efficiency (PAE) under the single tone stimulus. Up to 26.5 dBm output power can be achieved with an error vector magnitude (EVM) of lower than 3% under the 64QAM/OFDM WLAN stimulus. Project supported by the National Natural Science Foundation of China (No. 61201244) and the Natural Science Fund of SUES (No. E1-0501-14-0168).

Distributed Fair Auto Rate Medium Access Control for IEEE 802.11 Based WLANs

NASA Astrophysics Data System (ADS)

Zhu, Yanfeng; Niu, Zhisheng

Much research has shown that a carefully designed auto rate medium access control can utilize the underlying physical multi-rate capability to exploit the time-variation of the channel. In this paper, we develop a simple analytical model to elucidate the rule that maximizes the throughput of RTS/CTS based multi-rate wireless local area networks. Based on the discovered rule, we propose two distributed fair auto rate medium access control schemes called FARM and FARM+ from the view-point of throughput fairness and time-share fairness, respectively. With the proposed schemes, after receiving a RTS frame, the receiver selectively returns the CTS frame to inform the transmitter the maximum feasible rate probed by the signal-to-noise ratio of the received RTS frame. The key feature of the proposed schemes is that they are capable of maintaining throughput/time-share fairness in asymmetric situation where the distribution of SNR varies with stations. Extensive simulation results show that the proposed schemes outperform the existing throughput/time-share fair auto rate schemes in time-varying channel conditions.

A Reinforcement Sensor Embedded Vertical Handoff Controller for Vehicular Heterogeneous Wireless Networks

PubMed Central

Li, Limin; Xu, Yubin; Soong, Boon-Hee; Ma, Lin

2013-01-01

Vehicular communication platforms that provide real-time access to wireless networks have drawn more and more attention in recent years. IEEE 802.11p is the main radio access technology that supports communication for high mobility terminals, however, due to its limited coverage, IEEE 802.11p is usually deployed by coupling with cellular networks to achieve seamless mobility. In a heterogeneous cellular/802.11p network, vehicular communication is characterized by its short time span in association with a wireless local area network (WLAN). Moreover, for the media access control (MAC) scheme used for WLAN, the network throughput dramatically decreases with increasing user quantity. In response to these compelling problems, we propose a reinforcement sensor (RFS) embedded vertical handoff control strategy to support mobility management. The RFS has online learning capability and can provide optimal handoff decisions in an adaptive fashion without prior knowledge. The algorithm integrates considerations including vehicular mobility, traffic load, handoff latency, and network status. Simulation results verify that the proposed algorithm can adaptively adjust the handoff strategy, allowing users to stay connected to the best network. Furthermore, the algorithm can ensure that RSUs are adequate, thereby guaranteeing a high quality user experience. PMID:24193101

Media Access Time-Rearrangement of Wireless LAN for a Multi-Radio Collocated Platform

NASA Astrophysics Data System (ADS)

Shin, Sang-Heon; Kim, Chul; Park, Sang Kyu

With the advent of new Radio Access Technologies (RATs), it is inevitable that several RATs will co-exist, especially in the license-exempt band. In this letter, we present an in-depth adaptation of the proactive time-rearrangement (PATRA) scheme for IEEE 802.11 WLAN. The PATRA is a time division approach for reducing interference from a multi-radio device. Because IEEE 802.11 is based on carrier sensing and contention mechanism, it is the most suitable candidate to adapt the PATRA.

FDTD assessment of human exposure to electromagnetic fields from WiFi and bluetooth devices in some operating situations.

PubMed

Martínez-Búrdalo, M; Martín, A; Sanchis, A; Villar, R

2009-02-01

In this work, the numerical dosimetry in human exposure to the electromagnetic fields from antennas of wireless devices, such as those of wireless local area networks (WLAN) access points or phone and computer peripherals with Bluetooth antennas, is analyzed with the objective of assessing guidelines compliance. Several geometrical configurations are considered to simulate possible exposure situations of a person to the fields from WLAN or Bluetooth antennas operating at 2400 MHz. The exposure to radiation from two sources of different frequencies when using a 1800 MHz GSM mobile phone connected via Bluetooth with a hands-free car kit is also considered. The finite-difference time-domain (FDTD) method is used to calculate electric and magnetic field values in the vicinity of the antennas and specific absorption rates (SAR) in a high-resolution model of the human head and torso, to be compared with the limits from the guidelines (reference levels and basic restrictions, respectively). Results show that the exposure levels in worst-case situations studied are lower than those obtained when analyzing the exposure to mobile phones, as could be expected because of the low power of the signals and the distance between the human and the antennas, with both field and SAR values being far below the limits established by the guidelines, even when considering the combined exposure to both a GSM and a Bluetooth antenna. Copyright 2008 Wiley-Liss, Inc.

A Seamless Handoff Scheme with Access Point Load Balance for Real-Time Services Support in 802.11 Wireless LANs

NASA Astrophysics Data System (ADS)

Manodham, Thavisak; Loyola, Luis; Miki, Tetsuya

IEEE 802.11 wirelesses LANs (WLANs) have been rapidly deployed in enterprises, public areas, and households. Voice-over-IP (VoIP) and similar applications are now commonly used in mobile devices over wireless networks. Recent works have improved the quality of service (QoS) offering higher data rates to support various kinds of real-time applications. However, besides the need for higher data rates, seamless handoff and load balancing among APs are key issues that must be addressed in order to continue supporting real-time services across wireless LANs and providing fair services to all users. In this paper, we introduce a novel access point (AP) with two transceivers that improves network efficiency by supporting seamless handoff and traffic load balancing in a wireless network. In our proposed scheme, the novel AP uses the second transceiver to scan and find neighboring STAs in the transmission range and then sends the results to neighboring APs, which compare and analyze whether or not the STA should perform a handoff. The initial results from our simulations show that the novel AP module is more effective than the conventional scheme and a related work in terms of providing a handoff process with low latency and sharing traffic load with neighbor APs.

802.11ac WLAN MIMO radio-over-fiber distributed antenna system for in-building networks based on multicore fiber

NASA Astrophysics Data System (ADS)

Morant, Maria; Llorente, Roberto

2017-01-01

In this work we propose and evaluate experimentally the performance of IEEE 802.11ac WLAN standard signals in radio-over-fiber (RoF) distributed-antenna systems based on multicore fiber (MCF) for in-building WLAN connectivity. The RoF performance of WLAN signals with different bandwidth is investigated considering up to IEEE 802.11ac maximum of 160 MHz per user. We evaluate experimentally the performance of WLAN signals employing different modulation and coding schemes achieving bitrates from 78 Mbps to 1404 Mbps per user in distances up to 300 m in a 4-core MCF. The performance of the wireless standard multiple-input multiple-output (MIMO) processing algorithms included in WLAN signals applied to the RoF transmission in MCF optical systems is also evaluated. The impact on the quality of the signal from one of the cores in the MIMO processing is investigated and compared with the results achieved with single-input single-output (SISO) transmission in each core. We measured the error vector magnitude (EVM) and the OFDM data burst information of the received WLAN signals after RoF transmission for different distributed-antenna systems with uni- and bi-directional MCF communication. Finally, we compare the received EVM of a single-antenna system (SISO arrangement) with WLAN systems using two antennas (2×2 MIMO) and four antennas (4×4 MIMO).

Techno-Economic Analysis of FiWi Access Networks Based on 802.11ac WLAN and NG-PON2 Networks

NASA Astrophysics Data System (ADS)

Breskovic, Damir; Begusic, Dinko

2017-05-01

In this article, techno-economic analysis of a fiber-wireless access network is presented. With high bandwidth capacity of the gigabit passive optical network and with cost-effectiveness of very high throughput 802.11ac wireless local area networks that enable user mobility in the wireless segment, fiber-wireless access networks can be considered as an alternative to the fiber-to-the-home architecture for next generation access networks. Analysis based on the proposed scenario here, shows that a fiber-wireless access network is a more cost-effective solution in densely populated areas, but with some introduced improvements, even other geotypes can be considered as a commercially-viable solution.

Modern wireless telecommunication technologies and their electromagnetic compatibility with life-supporting equipment.

PubMed

Wallin, Mats K E B; Marve, Therese; Hakansson, Peter K

2005-11-01

Hospitals rely on pagers and ordinary telephones to reach staff members in emergency situations. New telecommunication technologies such as General Packet Radio Service (GPRS), the third generation mobile phone system Universal Mobile Telecommunications System (UMTS), and Wireless Local Area Network (WLAN) might be able to replace hospital pagers if they are electromagnetically compatible with medical devices. In this study, we sought to determine if GPRS, UMTS (Wideband Code Division Multiple Access-Frequency Division Duplex [WCDMA FDD]), and WLAN (IEEE 802.11b) transmitted signals interfere with life-supporting equipment in the intensive care and operating room environment. According to United States standard, ANSI C63.18-1997, laboratory tests were performed on 76 medical devices. In addition, clinical tests during 11 operations and 100 h of intensive care were performed. UMTS and WLAN signals caused little interference. Devices using these technologies can be used safely in critical care areas and during operations, but direct contact between medical devices and wireless communication devices ought to be avoided. In the case of GPRS, at a distance of 50 cm, it caused an older infusion pump to alarm and stop infusing; the pump had to be reset. Also, 10 cases of interference with device displays occurred. GPRS can be used safely at a distance of 1 m. Terminals/cellular phones using these technologies should be allowed without restriction in public areas because the risk of interference is minimal.

The Role of Wireless Computing Technology in the Design of Schools.

ERIC Educational Resources Information Center

Nair, Prakash

2003-01-01

After briefly describing the educational advantages of wireless networks using mobile computers, discusses the technical, operational, financial aspects of wireless local area networks (WLAN). Provides examples of school facilities designed for the use of WLAN. Includes a glossary of WLAN-related terms. (Contains 12 references.)

Implementation of Phased Array Antenna Technology Providing a Wireless Local Area Network to Enhance Port Security and Maritime Interdiction Operations

DTIC Science & Technology

2009-09-01

boarding team, COTS, WLAN, smart antenna, OpenVPN application, wireless base station, OFDM, latency, point-to-point wireless link. 16. PRICE CODE 17...16 c. SSL/TLS .................................17 2. OpenVPN ......................................17 III. EXPERIMENT METHODOLOGY...network frame at Layer 2 has already been secured by encryption at a higher level. 2. OpenVPN OpenVPN is open source software that provides a VPN

Design and fabrication of pHEMT MMIC switches for IEEE 802.11.a/b/g WLAN applications

NASA Astrophysics Data System (ADS)

Mun, Jae Kyoung; Ji, Hong Gu; Ahn, Hyokyun; Kim, Haecheon; Park, Chong-Ook

2005-08-01

In this paper, we propose a channel structure for a promising switch pHEMT with excellent isolation characteristics based on the distribution of electric field intensity beneath the Schottky contact in the transistor. Using the proposed device channel structure, SPST and SPDT switches were designed and fabricated, applicable to 2.4 GHz and 5.8 GHz WLAN systems. We discuss the relationship between dc characteristics and switch parameters in this paper in detail. The developed SPST switch exhibits a low insertion loss of 0.26 dB and a high isolation of 34.3 dB with a control voltage of 0 V/-3 V at 5.8 GHz. The SPDT also shows a good performance of 0.85 dB insertion loss and 31.5 dB isolation under the same conditions. The measured power-handling capability at 2.4 GHz reveals that the SPDT has an output power of 27 dBm at the 1 dB compression point and a third-order intercept point of more than 46 dBm.

Electromagnetic Interference of Wireless Local Area Network on Electrocardiogram Monitoring System: A Case Report

PubMed Central

Chung, Seungmin; Yi, Joohee

2013-01-01

Electromagnetic interference (EMI) can affect various medical devices. Herein, we report the case of EMI from wireless local area network (WLAN) on an electrocardiogram (ECG) monitoring system. A patient who had a prior myocardial infarction participated in the cardiac rehabilitation program in the sports medicine center of our hospital under the wireless ECG monitoring system. After WLAN was installed, wireless ECG monitoring system failed to show a proper ECG signal. ECG signal was distorted when WLAN was turned on, but it was normalized after turning off the WLAN. PMID:23613696

Determination of the duty cycle of WLAN for realistic radio frequency electromagnetic field exposure assessment.

PubMed

Joseph, Wout; Pareit, Daan; Vermeeren, Günter; Naudts, Dries; Verloock, Leen; Martens, Luc; Moerman, Ingrid

2013-01-01

Wireless Local Area Networks (WLANs) are commonly deployed in various environments. The WLAN data packets are not transmitted continuously but often worst-case exposure of WLAN is assessed, assuming 100% activity and leading to huge overestimations. Actual duty cycles of WLAN are thus of importance for time-averaging of exposure when checking compliance with international guidelines on limiting adverse health effects. In this paper, duty cycles of WLAN using Wi-Fi technology are determined for exposure assessment on large scale at 179 locations for different environments and activities (file transfer, video streaming, audio, surfing on the internet, etc.). The median duty cycle equals 1.4% and the 95th percentile is 10.4% (standard deviation SD = 6.4%). Largest duty cycles are observed in urban and industrial environments. For actual applications, the theoretical upper limit for the WLAN duty cycle is 69.8% and 94.7% for maximum and minimum physical data rate, respectively. For lower data rates, higher duty cycles will occur. Although counterintuitive at first sight, poor WLAN connections result in higher possible exposures. File transfer at maximum data rate results in median duty cycles of 47.6% (SD = 16%), while it results in median values of 91.5% (SD = 18%) at minimum data rate. Surfing and audio streaming are less intensively using the wireless medium and therefore have median duty cycles lower than 3.2% (SD = 0.5-7.5%). For a specific example, overestimations up to a factor 8 for electric fields occur, when considering 100% activity compared to realistic duty cycles. Copyright © 2012 Elsevier Ltd. All rights reserved.

Investigation of Doppler Effects on high mobility OFDM-MIMO systems with the support of High Altitude Platforms (HAPs)

NASA Astrophysics Data System (ADS)

Mohammed, H. A.; Sibley, M. J. N.; Mather, P. J.

2012-05-01

The merging of Orthogonal Frequency Division Multiplexing (OFDM) with Multiple-input multiple-output (MIMO) is a promising mobile air interface solution for next generation wireless local area networks (WLANs) and 4G mobile cellular wireless systems. This paper details the design of a highly robust and efficient OFDM-MIMO system to support permanent accessibility and higher data rates to users moving at high speeds, such as users travelling on trains. It has high relevance for next generation wireless local area networks (WLANs) and 4G mobile cellular wireless systems. The paper begins with a comprehensive literature review focused on both technologies. This is followed by the modelling of the OFDM-MIMO physical layer based on Simulink/Matlab that takes into consideration high vehicular mobility. Then the entire system is simulated and analysed under different encoding and channel estimation algorithms. The use of High Altitude Platform system (HAPs) technology is considered and analysed.

Tri-Band CPW-Fed Stub-Loaded Slot Antenna Design for WLAN/WiMAX Applications

NASA Astrophysics Data System (ADS)

Li, Jianxing; Guo, Jianying; He, Bin; Zhang, Anxue; Liu, Qing Huo

2016-11-01

A novel uniplanar CPW-fed tri-band stub-loaded slot antenna is proposed for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. Dual resonant modes were effectively excited in the upper band by using two identical pairs of slot stubs and parasitic slots symmetrically along the arms of a traditional CPW-fed slot dipole, achieving a much wider bandwidth. The middle band was realized by the fundamental mode of the slot dipole. To obtain the lower band, two identical inverted-L-shaped open-ended slots were symmetrically etched in the ground plane. A prototype was fabricated and measured, showing that tri-band operation with 10-dB return loss bandwidths of 150 MHz from 2.375 to 2.525 GHz, 725 MHz from 3.075 to 3.8 GHz, and 1.9 GHz from 5.0 to 6.9 GHz has been achieved. Details of the antenna design as well as the measured and simulated results are presented and discussed.

Design of Miniaturized Dual-Band Microstrip Antenna for WLAN Application

PubMed Central

Yang, Jiachen; Wang, Huanling; Lv, Zhihan; Wang, Huihui

2016-01-01

Wireless local area network (WLAN) is a technology that combines computer network with wireless communication technology. The 2.4 GHz and 5 GHz frequency bands in the Industrial Scientific Medical (ISM) band can be used in the WLAN environment. Because of the development of wireless communication technology and the use of the frequency bands without the need for authorization, the application of WLAN is becoming more and more extensive. As the key part of the WLAN system, the antenna must also be adapted to the development of WLAN communication technology. This paper designs two new dual-frequency microstrip antennas with the use of electromagnetic simulation software—High Frequency Structure Simulator (HFSS). The two antennas adopt ordinary FR4 material as a dielectric substrate, with the advantages of low cost and small size. The first antenna adopts microstrip line feeding, and the antenna radiation patch is composed of a folded T-shaped radiating dipole which reduces the antenna size, and two symmetrical rectangular patches located on both sides of the T-shaped radiating patch. The second antenna is a microstrip patch antenna fed by coaxial line, and the size of the antenna is diminished by opening a stepped groove on the two edges of the patch and a folded slot inside the patch. Simulation experiments prove that the two designed antennas have a higher gain and a favourable transmission characteristic in the working frequency range, which is in accordance with the requirements of WLAN communication. PMID:27355954

Design of Miniaturized Dual-Band Microstrip Antenna for WLAN Application.

PubMed

Yang, Jiachen; Wang, Huanling; Lv, Zhihan; Wang, Huihui

2016-06-27

Wireless local area network (WLAN) is a technology that combines computer network with wireless communication technology. The 2.4 GHz and 5 GHz frequency bands in the Industrial Scientific Medical (ISM) band can be used in the WLAN environment. Because of the development of wireless communication technology and the use of the frequency bands without the need for authorization, the application of WLAN is becoming more and more extensive. As the key part of the WLAN system, the antenna must also be adapted to the development of WLAN communication technology. This paper designs two new dual-frequency microstrip antennas with the use of electromagnetic simulation software-High Frequency Structure Simulator (HFSS). The two antennas adopt ordinary FR4 material as a dielectric substrate, with the advantages of low cost and small size. The first antenna adopts microstrip line feeding, and the antenna radiation patch is composed of a folded T-shaped radiating dipole which reduces the antenna size, and two symmetrical rectangular patches located on both sides of the T-shaped radiating patch. The second antenna is a microstrip patch antenna fed by coaxial line, and the size of the antenna is diminished by opening a stepped groove on the two edges of the patch and a folded slot inside the patch. Simulation experiments prove that the two designed antennas have a higher gain and a favourable transmission characteristic in the working frequency range, which is in accordance with the requirements of WLAN communication.

Cognitive Radio Networks for Tactical Wireless Communications

DTIC Science & Technology

2014-12-01

exists. Instead, security is an evolving process, as we have seen in the context of WLANs and 2G / 3G networks. New system vulnerabilities continue to...in the network configuration and radio parameters take place due to mobility of platforms, and variation in other users of the RF environment. CRNs...dynamic spectrum access experimentally, and it represents the largest military Mobile Ad hoc Network (MANET) as of today. The WNaN demonstrator has been

A dual-band reconfigurable Yagi-Uda antenna with diverse radiation patterns

NASA Astrophysics Data System (ADS)

Saurav, Kushmanda; Sarkar, Debdeep; Srivastava, Kumar Vaibhav

2017-07-01

In this paper, a dual-band pattern reconfigurable antenna is proposed. The antenna comprises of a dual-band complementary split ring resonators (CSRRs) loaded dipole as the driven element and two copper strips with varying lengths as parasitic segments on both sides of the driven dipole. PIN diodes are used with the parasitic elements to control their electrical length. The CSRRs loading provide a lower order mode in addition to the reference dipole mode, while the parasitic elements along with the PIN diodes are capable of switching the omni-directional radiation of the dual-band driven element to nine different configurations of radiation patterns which include bi-directional end-fire, broadside, and uni-directional end-fire in both the operating bands. A prototype of the designed antenna together with the PIN diodes and DC bias lines is fabricated to validate the concept of dual-band radiation pattern diversity. The simulation and measurement results are in good agreement. The proposed antenna can be used in wireless access points for PCS and WLAN applications.

Testing and reference model analysis of FTTH system

NASA Astrophysics Data System (ADS)

Feng, Xiancheng; Cui, Wanlong; Chen, Ying

2009-08-01

With rapid development of Internet and broadband access network, the technologies of xDSL, FTTx+LAN , WLAN have more applications, new network service emerges in endless stream, especially the increase of network game, meeting TV, video on demand, etc. FTTH supports all present and future service with enormous bandwidth, including traditional telecommunication service, traditional data service and traditional TV service, and the future digital TV and VOD. With huge bandwidth of FTTH, it wins the final solution of broadband network, becomes the final goal of development of optical access network.. Fiber to the Home (FTTH) will be the goal of telecommunications cable broadband access. In accordance with the development trend of telecommunication services, to enhance the capacity of integrated access network, to achieve triple-play (voice, data, image), based on the existing optical Fiber to the curb (FTTC), Fiber To The Zone (FTTZ), Fiber to the Building (FTTB) user optical cable network, the optical fiber can extend to the FTTH system of end-user by using EPON technology. The article first introduced the basic components of FTTH system; and then explain the reference model and reference point for testing of the FTTH system; Finally, by testing connection diagram, the testing process, expected results, primarily analyze SNI Interface Testing, PON interface testing, Ethernet performance testing, UNI interface testing, Ethernet functional testing, PON functional testing, equipment functional testing, telephone functional testing, operational support capability testing and so on testing of FTTH system. ...

Next Generation Information Systems Architectures

DTIC Science & Technology

2008-07-01

constraint, accessories such as bulk data storage, radio cards , and batteries also need to be accommodated. Some applications would require the...exhibition demonstrated a number of WLAN applications on an existing smartphone handset by using a WLAN card inserted into the SD card slot.4 Another...that only loose coupling is implemented. There are also less integrated methods, such as using a GPRS/WLAN PC card in a PC or PDA to allow it to use

Cmos spdt switch for wlan applications

NASA Astrophysics Data System (ADS)

Bhuiyan, M. A. S.; Reaz, M. B. I.; Rahman, L. F.; Minhad, K. N.

2015-04-01

WLAN has become an essential part of our today's life. The advancement of CMOS technology let the researchers contribute low power, size and cost effective WLAN devices. This paper proposes a single pole double through transmit/receive (T/R) switch for WLAN applications in 0.13 μm CMOS technology. The proposed switch exhibit 1.36 dB insertion loss, 25.3 dB isolation and 24.3 dBm power handling capacity. Moreover, it only dissipates 786.7 nW power per cycle. The switch utilizes only transistor aspect ratio optimization and resistive body floating technique to achieve such desired performance. In this design the use of bulky inductor and capacitor is avoided to evade imposition of unwanted nonlinearities to the communication signal.

Fragility issues of medical video streaming over 802.11e-WLAN m-health environments.

PubMed

Tan, Yow-Yiong Edwin; Philip, Nada; Istepanian, Robert H

2006-01-01

This paper presents some of the fragility issues of a medical video streaming over 802.11e-WLAN in m-health applications. In particular, we present a medical channel-adaptive fair allocation (MCAFA) scheme for enhanced QoS support for IEEE 802.11 (WLAN), as a modification for the standard 802.11e enhanced distributed coordination function (EDCF) is proposed for enhanced medical data performance. The medical channel-adaptive fair allocation (MCAFA) proposed extends the EDCF, by halving the contention window (CW) after zeta consecutive successful transmissions to reduce the collision probability when channel is busy. Simulation results show that MCAFA outperforms EDCF in-terms of overall performance relevant to the requirements of high throughput of medical data and video streaming traffic in 3G/WLAN wireless environments.

Kalman filter with a linear state model for PDR+WLAN positioning and its application to assisting a particle filter

NASA Astrophysics Data System (ADS)

Raitoharju, Matti; Nurminen, Henri; Piché, Robert

2015-12-01

Indoor positioning based on wireless local area network (WLAN) signals is often enhanced using pedestrian dead reckoning (PDR) based on an inertial measurement unit. The state evolution model in PDR is usually nonlinear. We present a new linear state evolution model for PDR. In simulated-data and real-data tests of tightly coupled WLAN-PDR positioning, the positioning accuracy with this linear model is better than with the traditional models when the initial heading is not known, which is a common situation. The proposed method is computationally light and is also suitable for smoothing. Furthermore, we present modifications to WLAN positioning based on Gaussian coverage areas and show how a Kalman filter using the proposed model can be used for integrity monitoring and (re)initialization of a particle filter.

Multidimensional Optimization of Signal Space Distance Parameters in WLAN Positioning

PubMed Central

Brković, Milenko; Simić, Mirjana

2014-01-01

Accurate indoor localization of mobile users is one of the challenging problems of the last decade. Besides delivering high speed Internet, Wireless Local Area Network (WLAN) can be used as an effective indoor positioning system, being competitive both in terms of accuracy and cost. Among the localization algorithms, nearest neighbor fingerprinting algorithms based on Received Signal Strength (RSS) parameter have been extensively studied as an inexpensive solution for delivering indoor Location Based Services (LBS). In this paper, we propose the optimization of the signal space distance parameters in order to improve precision of WLAN indoor positioning, based on nearest neighbor fingerprinting algorithms. Experiments in a real WLAN environment indicate that proposed optimization leads to substantial improvements of the localization accuracy. Our approach is conceptually simple, is easy to implement, and does not require any additional hardware. PMID:24757443

Ubiquitous health monitoring system for multiple users using a ZigBee and WLAN dual-network.

PubMed

Cha, Yong Dae; Yoon, Gilwon

2009-11-01

A ubiquitous health monitoring system for multiple users was developed based on a ZigBee and wireless local area network (WLAN) dual-network. A compact biosignal monitoring unit (BMU) for measuring electrocardiogram (ECG), photoplethysmogram (PPG), and temperature was also developed. A single 8-bit microcontroller operated the BMU including most of digital filtering and wireless communication. The BMU with its case was reduced to 55 x 35 x 15 mm and 33 g. In routine use, vital signs of 6 bytes/sec (heart rate, temperature, pulse transit time) per each user were transmitted through a ZigBee module even though all the real-time data were recorded in a secure digital memory of the BMU. In an emergency or when need arises, a channel of a particular user was switched to another ZigBee module, called the emergency module, that sent all ECG and PPG waveforms in real time. Each emergency ZigBee module handled up to a few users. Data from multiple users were wirelessly received by the ZigBee receiver modules in a controller called ZigBee-WLAN gateway, where the ZigBee modules were connected to a WLAN module. This WLAN module sent all data wirelessly to a monitoring center. Operating the dual modes of ZigBee/WLAN utilized an advantage of ZigBee by handling multiple users with minimum power consumption, and overcame the ZigBee limitation of low data rate. This dual-network system for LAN is economically competitive and reliable.

PRIMAL: Page Rank-Based Indoor Mapping and Localization Using Gene-Sequenced Unlabeled WLAN Received Signal Strength

PubMed Central

Zhou, Mu; Zhang, Qiao; Xu, Kunjie; Tian, Zengshan; Wang, Yanmeng; He, Wei

2015-01-01

Due to the wide deployment of wireless local area networks (WLAN), received signal strength (RSS)-based indoor WLAN localization has attracted considerable attention in both academia and industry. In this paper, we propose a novel page rank-based indoor mapping and localization (PRIMAL) by using the gene-sequenced unlabeled WLAN RSS for simultaneous localization and mapping (SLAM). Specifically, first of all, based on the observation of the motion patterns of the people in the target environment, we use the Allen logic to construct the mobility graph to characterize the connectivity among different areas of interest. Second, the concept of gene sequencing is utilized to assemble the sporadically-collected RSS sequences into a signal graph based on the transition relations among different RSS sequences. Third, we apply the graph drawing approach to exhibit both the mobility graph and signal graph in a more readable manner. Finally, the page rank (PR) algorithm is proposed to construct the mapping from the signal graph into the mobility graph. The experimental results show that the proposed approach achieves satisfactory localization accuracy and meanwhile avoids the intensive time and labor cost involved in the conventional location fingerprinting-based indoor WLAN localization. PMID:26404274

A Smartphone Indoor Localization Algorithm Based on WLAN Location Fingerprinting with Feature Extraction and Clustering.

PubMed

Luo, Junhai; Fu, Liang

2017-06-09

With the development of communication technology, the demand for location-based services is growing rapidly. This paper presents an algorithm for indoor localization based on Received Signal Strength (RSS), which is collected from Access Points (APs). The proposed localization algorithm contains the offline information acquisition phase and online positioning phase. Firstly, the AP selection algorithm is reviewed and improved based on the stability of signals to remove useless AP; secondly, Kernel Principal Component Analysis (KPCA) is analyzed and used to remove the data redundancy and maintain useful characteristics for nonlinear feature extraction; thirdly, the Affinity Propagation Clustering (APC) algorithm utilizes RSS values to classify data samples and narrow the positioning range. In the online positioning phase, the classified data will be matched with the testing data to determine the position area, and the Maximum Likelihood (ML) estimate will be employed for precise positioning. Eventually, the proposed algorithm is implemented in a real-world environment for performance evaluation. Experimental results demonstrate that the proposed algorithm improves the accuracy and computational complexity.

A Novel Hybrid Intelligent Indoor Location Method for Mobile Devices by Zones Using Wi-Fi Signals

PubMed Central

Castañón–Puga, Manuel; Salazar, Abby Stephanie; Aguilar, Leocundo; Gaxiola-Pacheco, Carelia; Licea, Guillermo

2015-01-01

The increasing use of mobile devices in indoor spaces brings challenges to location methods. This work presents a hybrid intelligent method based on data mining and Type-2 fuzzy logic to locate mobile devices in an indoor space by zones using Wi-Fi signals from selected access points (APs). This approach takes advantage of wireless local area networks (WLANs) over other types of architectures and implements the complete method in a mobile application using the developed tools. Besides, the proposed approach is validated by experimental data obtained from case studies and the cross-validation technique. For the purpose of generating the fuzzy rules that conform to the Takagi–Sugeno fuzzy system structure, a semi-supervised data mining technique called subtractive clustering is used. This algorithm finds centers of clusters from the radius map given by the collected signals from APs. Measurements of Wi-Fi signals can be noisy due to several factors mentioned in this work, so this method proposed the use of Type-2 fuzzy logic for modeling and dealing with such uncertain information. PMID:26633417

A Novel Hybrid Intelligent Indoor Location Method for Mobile Devices by Zones Using Wi-Fi Signals.

PubMed

Castañón-Puga, Manuel; Salazar, Abby Stephanie; Aguilar, Leocundo; Gaxiola-Pacheco, Carelia; Licea, Guillermo

2015-12-02

The increasing use of mobile devices in indoor spaces brings challenges to location methods. This work presents a hybrid intelligent method based on data mining and Type-2 fuzzy logic to locate mobile devices in an indoor space by zones using Wi-Fi signals from selected access points (APs). This approach takes advantage of wireless local area networks (WLANs) over other types of architectures and implements the complete method in a mobile application using the developed tools. Besides, the proposed approach is validated by experimental data obtained from case studies and the cross-validation technique. For the purpose of generating the fuzzy rules that conform to the Takagi-Sugeno fuzzy system structure, a semi-supervised data mining technique called subtractive clustering is used. This algorithm finds centers of clusters from the radius map given by the collected signals from APs. Measurements of Wi-Fi signals can be noisy due to several factors mentioned in this work, so this method proposed the use of Type-2 fuzzy logic for modeling and dealing with such uncertain information.

Remote monitoring of electromagnetic signals and seismic events using smart mobile devices

NASA Astrophysics Data System (ADS)

Georgiadis, Pantelis; Cavouras, Dionisis; Sidiropoulos, Konstantinos; Ninos, Konstantinos; Nomicos, Constantine

2009-06-01

This study presents the design and development of a novel mobile wireless system to be used for monitoring seismic events and related electromagnetic signals, employing smart mobile devices like personal digital assistants (PDAs) and wireless communication technologies such as wireless local area networks (WLANs), general packet radio service (GPRS) and universal mobile telecommunications system (UMTS). The proposed system enables scientists to access critical data while being geographically independent of the sites of data sources, rendering it as a useful tool for preliminary scientific analysis.

Aspect Ratio of Receiver Node Geometry based Indoor WLAN Propagation Model

NASA Astrophysics Data System (ADS)

Naik, Udaykumar; Bapat, Vishram N.

2017-08-01

This paper presents validation of indoor wireless local area network (WLAN) propagation model for varying rectangular receiver node geometry. The rectangular client node configuration is a standard node arrangement in computer laboratories of academic institutes and research organizations. The model assists to install network nodes for the better signal coverage. The proposed model is backed by wide ranging real time received signal strength measurements at 2.4 GHz. The shadow fading component of signal propagation under realistic indoor environment is modelled with the dependency on varying aspect ratio of the client node geometry. The developed new model is useful in predicting indoor path loss for IEEE 802.11b/g WLAN. The new model provides better performance in comparison to well known International Telecommunication Union and free space propagation models. It is shown that the proposed model is simple and can be a useful tool for indoor WLAN node deployment planning and quick method for the best utilisation of the office space.

Wireless Networks: New Meaning to Ubiquitous Computing.

ERIC Educational Resources Information Center

Drew, Wilfred, Jr.

2003-01-01

Discusses the use of wireless technology in academic libraries. Topics include wireless networks; standards (IEEE 802.11); wired versus wireless; why libraries implement wireless technology; wireless local area networks (WLANs); WLAN security; examples of wireless use at Indiana State University and Morrisville College (New York); and useful…

Secure Wireless Networking at Simon Fraser University.

ERIC Educational Resources Information Center

Johnson, Worth

2003-01-01

Describes the wireless local area network (WLAN) at Simon Fraser University, British Columbia, Canada. Originally conceived to address computing capacity and reduce university computer space demands, the WLAN has provided a seamless computing environment for students and solved a number of other campus problems as well. (SLD)

The Brave New World of Wireless Technologies: A Primer for Educators.

ERIC Educational Resources Information Center

Boerner, Gerald L.

2002-01-01

Discusses the use of wireless local area networks (WLANs) on college campuses. Highlights include traditional wired networks; cost, speed, and reliability; wireless networking standards; mobility; installation speed, simplicity, and flexibility; reduced cost of ownership; scalability; security issues; and a glossary of WLAN terms. (LRW)

Real time network traffic monitoring for wireless local area networks based on compressed sensing

NASA Astrophysics Data System (ADS)

Balouchestani, Mohammadreza

2017-05-01

A wireless local area network (WLAN) is an important type of wireless networks which connotes different wireless nodes in a local area network. WLANs suffer from important problems such as network load balancing, large amount of energy, and load of sampling. This paper presents a new networking traffic approach based on Compressed Sensing (CS) for improving the quality of WLANs. The proposed architecture allows reducing Data Delay Probability (DDP) to 15%, which is a good record for WLANs. The proposed architecture is increased Data Throughput (DT) to 22 % and Signal to Noise (S/N) ratio to 17 %, which provide a good background for establishing high qualified local area networks. This architecture enables continuous data acquisition and compression of WLAN's signals that are suitable for a variety of other wireless networking applications. At the transmitter side of each wireless node, an analog-CS framework is applied at the sensing step before analog to digital converter in order to generate the compressed version of the input signal. At the receiver side of wireless node, a reconstruction algorithm is applied in order to reconstruct the original signals from the compressed signals with high probability and enough accuracy. The proposed algorithm out-performs existing algorithms by achieving a good level of Quality of Service (QoS). This ability allows reducing 15 % of Bit Error Rate (BER) at each wireless node.

Exposure to radio frequency electromagnetic fields from wireless computer networks: duty factors of Wi-Fi devices operating in schools.

PubMed

Khalid, M; Mee, T; Peyman, A; Addison, D; Calderon, C; Maslanyj, M; Mann, S

2011-12-01

The growing use of wireless local area networks (WLAN) in schools has prompted a study to investigate exposure to the radio frequency (RF) electromagnetic fields from Wi-Fi devices. International guidelines on limiting the adverse health effects of RF, such as those of ICNIRP, allow for time-averaging of exposure. Thus, as Wi-Fi signals consist of intermittent bursts of RF energy, it is important to consider the duty factors of devices in assessing the extent of exposure and compliance with guidelines. Using radio packet capture methods, the duty factor of Wi-Fi devices has been assessed in a sample of 6 primary and secondary schools during classroom lessons. For the 146 individual laptops investigated, the range of duty factors was from 0.02 to 0.91%, with a mean of 0.08% (SD 0.10%). The duty factors of access points from 7 networks ranged from 1.0% to 11.7% with a mean of 4.79% (SD 3.76%). Data gathered with transmit time measuring devices attached to laptops also showed similar results. Within the present limited sample, the range of duty factors from laptops and access points were found to be broadly similar for primary and secondary schools. Applying these duty factors to previously published results from this project, the maximum time-averaged power density from a laptop would be 220 μW m(-2), at a distance of 0.5 m and the peak localised SAR predicted in the torso region of a 10 year old child model, at 34 cm from the antenna, would be 80 μW kg(-1). Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Spontaneous Group Learning in Ambient Learning Environments

NASA Astrophysics Data System (ADS)

Bick, Markus; Jughardt, Achim; Pawlowski, Jan M.; Veith, Patrick

Spontaneous Group Learning is a concept to form and facilitate face-to-face, ad-hoc learning groups in collaborative settings. We show how to use Ambient Intelligence to identify, support, and initiate group processes. Learners' positions are determined by widely used technologies, e.g., Bluetooth and WLAN. As a second step, learners' positions, tasks, and interests are visualized. Finally, a group process is initiated supported by relevant documents and services. Our solution is a starting point to develop new didactical solutions for collaborative processes.

SEMICONDUCTOR INTEGRATED CIRCUITS: A reconfigurable analog baseband circuit for WLAN, WCDMA, and Bluetooth

NASA Astrophysics Data System (ADS)

Tao, Tong; Baoyong, Chi; Ziqiang, Wang; Ying, Zhang; Hanjun, Jiang; Zhihua, Wang

2010-05-01

A reconfigurable analog baseband circuit for WLAN, WCDMA, and Bluetooth in 0.35 μm CMOS is presented. The circuit consists of two variable gain amplifiers (VGA) in cascade and a Gm-C elliptic low-pass filter (LPF). The filter-order and the cut-off frequency of the LPF can be reconfigured to satisfy the requirements of various applications. In order to achieve the optimum power consumption, the bandwidth of the VGAs can also be dynamically reconfigured and some Gm cells can be cut off in the given application. Simulation results show that the analog baseband circuit consumes 16.8 mW for WLAN, 8.9 mW for WCDMA and only 6.5 mW for Bluetooth, all with a 3 V power supply. The analog baseband circuit could provide -10 to +40 dB variable gain, third-order low pass filtering with 1 MHz cut-off frequency for Bluetooth, fourth-order low pass filtering with 2.2 MHz cut-off frequency for WCDMA, and fifth-order low pass filtering with 11 MHz cut-off frequency for WLAN, respectively.

Potential for Personal Digital Assistant interference with implantable cardiac devices.

PubMed

Tri, Jeffrey L; Trusty, Jane M; Hayes, David L

2004-12-01

To determine whether the wireless local area network (WLAN) technology, specifically the Personal Digital Assistant (PDA), interferes with implantable cardiac pacemakers and defibrillators. Various pacemakers and defibrillators were tested in vitro at the Mayo Clinic in Rochester, Minn, between March 6 and July 30, 2003. These cardiac devices were exposed to an HP Compaq IPAQ PDA fitted with a Cisco Aironet WLAN card. Initial testing was designed to show whether the Aironet card radiated energy in a consistent pattern from the antenna of the PDA to ensure that subsequent cardiac device testing would not be affected by the orientation of the PDA to the cardiac device. Testing involved placing individual cardiac devices in a simulator and uniformly exposing each device at its most sensitive programmable value to the WLAN card set to maximum power. During testing with the Cisco WLAN Aironet card, all devices programmed to the unipolar or bipolar configuration single- or dual-chamber mode had normal pacing and sensing functions and exhibited no effects of electromagnetic interference except for 1 implantable cardioverter-defibrillator (ICD). This aberration was determined to relate to the design of the investigators' testing apparatus and not to the output of the PDA. The ICD device appropriately identified and labeled the electromagnetic aberration as "noise." We documented no electromagnetic interference caused by the WLAN technology by using in vitro testing of pacemakers and ICDs; however, testing ideally should be completed in vivo to confirm the lack of any clinically important interactions.

A Secure and Efficient Handover Authentication Protocol for Wireless Networks

PubMed Central

Wang, Weijia; Hu, Lei

2014-01-01

Handover authentication protocol is a promising access control technology in the fields of WLANs and mobile wireless sensor networks. In this paper, we firstly review an efficient handover authentication protocol, named PairHand, and its existing security attacks and improvements. Then, we present an improved key recovery attack by using the linearly combining method and reanalyze its feasibility on the improved PairHand protocol. Finally, we present a new handover authentication protocol, which not only achieves the same desirable efficiency features of PairHand, but enjoys the provable security in the random oracle model. PMID:24971471

Adaptive Indoor Positioning Model Based on WLAN-Fingerprinting for Dynamic and Multi-Floor Environments

PubMed Central

Alshami, Iyad Husni; Sahibuddin, Shamsul; Firdaus, Firdaus

2017-01-01

The Global Positioning System demonstrates the significance of Location Based Services but it cannot be used indoors due to the lack of line of sight between satellites and receivers. Indoor Positioning Systems are needed to provide indoor Location Based Services. Wireless LAN fingerprints are one of the best choices for Indoor Positioning Systems because of their low cost, and high accuracy, however they have many drawbacks: creating radio maps is time consuming, the radio maps will become outdated with any environmental change, different mobile devices read the received signal strength (RSS) differently, and peoples’ presence in LOS between access points and mobile device affects the RSS. This research proposes a new Adaptive Indoor Positioning System model (called DIPS) based on: a dynamic radio map generator, RSS certainty technique and peoples’ presence effect integration for dynamic and multi-floor environments. Dynamic in our context refers to the effects of people and device heterogeneity. DIPS can achieve 98% and 92% positioning accuracy for floor and room positioning, and it achieves 1.2 m for point positioning error. RSS certainty enhanced the positioning accuracy for floor and room for different mobile devices by 11% and 9%. Then by considering the peoples’ presence effect, the error is reduced by 0.2 m. In comparison with other works, DIPS achieves better positioning without extra devices. PMID:28783047

Analysis and Design of Complex Networks

DTIC Science & Technology

2014-12-02

systems. 08-NOV-10, . : , Barlas Oguz, Venkat Anantharam. Long range dependent Markov chains with applications , Information Theory and Applications ...JUL-12, . : , Michael Krishnan, Ehsan Haghani, Avideh Zakhor. Packet Length Adaptation in WLANs with Hidden Nodes and Time-Varying Channels, IEEE... WLAN networks with multi-antenna beam-forming nodes. VII. Use of busy/idle signals for discovering optimum AP association VIII

Wireless mesh networks.

PubMed

Wang, Xinheng

2008-01-01

Wireless telemedicine using GSM and GPRS technologies can only provide low bandwidth connections, which makes it difficult to transmit images and video. Satellite or 3G wireless transmission provides greater bandwidth, but the running costs are high. Wireless networks (WLANs) appear promising, since they can supply high bandwidth at low cost. However, the WLAN technology has limitations, such as coverage. A new wireless networking technology named the wireless mesh network (WMN) overcomes some of the limitations of the WLAN. A WMN combines the characteristics of both a WLAN and ad hoc networks, thus forming an intelligent, large scale and broadband wireless network. These features are attractive for telemedicine and telecare because of the ability to provide data, voice and video communications over a large area. One successful wireless telemedicine project which uses wireless mesh technology is the Emergency Room Link (ER-LINK) in Tucson, Arizona, USA. There are three key characteristics of a WMN: self-organization, including self-management and self-healing; dynamic changes in network topology; and scalability. What we may now see is a shift from mobile communication and satellite systems for wireless telemedicine to the use of wireless networks based on mesh technology, since the latter are very attractive in terms of cost, reliability and speed.

An Optimized 2.4GHz RF Power Amplifier Performance for WLAN System

NASA Astrophysics Data System (ADS)

Ali, Mohammed H.; Chakrabarty, C. K.; Abdalla, Ahmed N.; Hock, Goh C.

2013-06-01

Recently, the design of RF power amplifiers (PAs) for modern wireless systems are faced with a difficult tradeoff for example, cellphone; battery lifetime is largely determined by the power efficiency of the PA and high spectral efficiency which have ability to transmit data at the highest possible rate for a given channel bandwidth. This paper presents the design a multi stage class AB power Amplifier with high power added efficiency (PAE) and acceptable linearity for the WLAN applications. The open-circuited third harmonic control circuit enhances the efficiency of the PA without deteriorating the linearity of class-AB mode of the PA. The voltage and current waveforms are simulated to evaluate the appropriate operation for the modes. The effectiveness of the proposed controller has been verified by comparing proposed method with another methods using simulation study under a variety of conditions. The proposed circuit operation for a WLAN signals delivers a power-added efficiency (PAE) of 37.6% is measured at 31.6-dBm output power while dissipating 34.61 mA from a 1.8V supply. Finally, the proposed PA is show a good and acceptable result for the WLAN system.

A pervasive health monitoring service system based on ubiquitous network technology.

PubMed

Lin, Chung-Chih; Lee, Ren-Guey; Hsiao, Chun-Chieh

2008-07-01

The phenomenon of aging society has derived problems such as shortage of medical resources and reduction of quality in healthcare services. This paper presents a system infrastructure for pervasive and long-term healthcare applications, i.e. a ubiquitous network composed of wireless local area network (WLAN) and cable television (CATV) network serving as a platform for monitoring physiological signals. Users can record vital signs including heart rate, blood pressure, and body temperature anytime either at home or at frequently visited public places in order to create a personal health file. The whole system was formally implemented in December 2004. Analysis of 2000 questionnaires indicates that 85% of users were satisfied with the provided community-wide healthcare services. Among the services provided by our system, health consultation services offered by family doctors was rated the most important service by 17.9% of respondents, and was followed by control of one's own health condition (16.4% of respondents). Convenience of data access was rated most important by roughly 14.3% of respondents. We proposed and implemented a long-term healthcare system integrating WLAN and CATV networks in the form of a ubiquitous network providing a service platform for physiological monitoring. This system can classify the health levels of the resident according to the variation tendency of his or her physiological signal for important reference of health management.

Exploiting Spatial Channel Occupancy Information in WLANs

DTIC Science & Technology

2014-05-15

transmit signal UDP user datagram protocol WLAN wireless local area network ix Acknowledgements I owe a great debt of gratitude to my advisor, Professor...information. Unlike in wired networks , each node in a wireless network observes a different medium depending on its location. As a result, standard local... wireless LANs [15, 23, 29]. In [23], Li et. al. model the throughput of an 802.11 network using full spatial information. Their approach is from a

Forensic Carving of Network Packets and Associated Data Structures

DTIC Science & Technology

2011-01-01

establishment of prior connection activity and services used; identification of other systems present on the system’s LAN or WLAN; geolocation of the...identification of other systems present on the system?s LAN or WLAN; geolocation of the host computer system; and cross-drive analysis. We show that network...Finally, our work in geolocation was assisted by geo- location databases created by companies such as Google (Google Mobile, 2011) and Skyhook

Propagation Characteristics of International Space Station Wireless Local Area Network

NASA Technical Reports Server (NTRS)

Sham, Catherine C.; Hwn, Shian U.; Loh, Yin-Chung

2005-01-01

This paper describes the application of the Uniform Geometrical Theory of Diffraction (UTD) for Space Station Wireless Local Area Networks (WLANs) indoor propagation characteristics analysis. The verification results indicate good correlation between UTD computed and measured signal strength. It is observed that the propagation characteristics are quite different in the Space Station modules as compared with those in the typical indoor WLANs environment, such as an office building. The existing indoor propagation models are not readily applicable to the Space Station module environment. The Space Station modules can be regarded as oversized imperfect waveguides. Two distinct propagation regions separated by a breakpoint exist. The propagation exhibits the guided wave characteristics. The propagation loss in the Space Station, thus, is much smaller than that in the typical office building. The path loss model developed in this paper is applicable for Space Station WLAN RF coverage and link performance analysis.

High Dynamic Range Cognitive Radio Front Ends: Architecture to Evaluation

NASA Astrophysics Data System (ADS)

Ashok, Arun; Subbiah, Iyappan; Varga, Gabor; Schrey, Moritz; Heinen, Stefan

2016-07-01

Advent of TV white space digitization has released frequencies from 470 MHz to 790 MHz to be utilized opportunistically. The secondary user can utilize these so called TV spaces in the absence of primary users. The most important challenge for this coexistence is mutual interference. While the strong TV stations can completely saturate the receiver of the cognitive radio (CR), the cognitive radio spurious tones can disturb other primary users and white space devices. The aim of this paper is to address the challenges for enabling cognitive radio applications in WLAN and LTE. In this process, architectural considerations for the design of cognitive radio front ends are discussed. With high-IF converters, faster and flexible implementation of CR enabled WLAN and LTE are shown. The effectiveness of the architecture is shown by evaluating the CR front ends for compliance of standards namely 802.11b/g (WLAN) and 3GPP TS 36.101 (LTE).

A 3.2-GHz fully integrated low-phase noise CMOS VCO with self-biasing current source for the IEEE 802.11a/hiperLAN WLAN standard

NASA Astrophysics Data System (ADS)

Quemada, C.; Adin, I.; Bistue, G.; Berenguer, R.; Mendizabal, J.

2005-06-01

A 3.3V, fully integrated 3.2-GHz voltage-controlled oscillator (VCO) is designed in a 0.18μm CMOS technology for the IEE 802.11a/HiperLAN WLAN standard for the UNII band from 5.15 to 5.35 GHz. The VCO is tunable between 2.85 GHz and 3.31 GHz. NMOS architecture with self-biasing current of the tank source is chosen. A startup circuit has been employed to avoid zero initial current. Current variation is lower than 1% for voltage supply variations of 10%. The use of a self-biasing current source in the tank provides a greater safety in the transconductance value and allows running along more extreme point operation The designed VCO displays a phase noise and output power of -98dBc/Hz (at 100 KHz offset frequency) and 0dBm respectively. This phase noise has been obtained with inductors of 2.2nH and quality factor of 12 at 3.2 GHz, and P-N junction varactors whose quality factor is estimated to exceed 40 at 3.2 GHz. These passive components have been fabricated, measured and modeled previously. The core of the VCO consumes 33mW DC power.

Compact Planar Ultrawideband Antennas with 3.5/5.2/5.8 GHz Triple Band-Notched Characteristics for Internet of Things Applications.

PubMed

Dong, Jian; Li, Qianqian; Deng, Lianwen

2017-02-10

Ultrawideband (UWB) antennas, as core devices in high-speed wireless communication, are widely applied to mobile handsets, wireless sensor networks, and Internet of Things (IoT). A compact printed monopole antenna for UWB applications with triple band-notched characteristics is proposed in this paper. The antenna has a very compact size of 10 x 16 mm2 and is composed of a square slotted radiation patch and a narrow rectangular ground plane on the back of the substrate. First, by etching a pair of inverted T-shaped slots at the bottom of the radiation patch, one notched band at 5-6 GHz for rejecting the Wireless Local Area Network (WLAN) is generated. Then, by cutting a comb-shaped slot on the top of the radiation patch, a second notched band for rejecting 3.5 GHz Worldwide Interoperability for Microwave Access (WiMAX) is obtained. Further, by cutting a pair of rectangular slots and a C-shaped slot as well as adding a pair of small square parasitic patches at the center of the radiating patch, two separate notched bands for rejecting 5.2 GHz lower WLAN and 5.8 GHz upper WLAN are realized, respectively. Additionally, by integrating the slotted radiation patch with the narrow rectangular ground plane, an enhanced impedance bandwidth can be achieved, especially at the higher band. The antenna consists of linear symmetrical sections only and is easy for fabrication and fine-tuning. The measured results show that the designed antenna provides a wide impedance bandwidth of 150% from 2.12 to 14.80 GHz for VSWR < 2, except for three notched bands of 3.36-4.16, 4.92-5.36, and 5.68-6.0 GHz. Additionally, the antenna exhibits nearly omnidirectional radiation characteristics, low gain at the stopbands, and flat group delay over the whole UWB except at the stopbands. Simulated and experimental results show that the proposed antenna can provide good frequency-domain and time-domain performances at desired UWB frequencies and be an attractive candidate for portable IoT applications.

Compact Planar Ultrawideband Antennas with 3.5/5.2/5.8 GHz Triple Band-Notched Characteristics for Internet of Things Applications

PubMed Central

Dong, Jian; Li, Qianqian; Deng, Lianwen

2017-01-01

Ultrawideband (UWB) antennas, as core devices in high-speed wireless communication, are widely applied to mobile handsets, wireless sensor networks, and Internet of Things (IoT). A compact printed monopole antenna for UWB applications with triple band-notched characteristics is proposed in this paper. The antenna has a very compact size of 10 × 16 mm2 and is composed of a square slotted radiation patch and a narrow rectangular ground plane on the back of the substrate. First, by etching a pair of inverted T-shaped slots at the bottom of the radiation patch, one notched band at 5–6 GHz for rejecting the Wireless Local Area Network (WLAN) is generated. Then, by cutting a comb-shaped slot on the top of the radiation patch, a second notched band for rejecting 3.5 GHz Worldwide Interoperability for Microwave Access (WiMAX) is obtained. Further, by cutting a pair of rectangular slots and a C-shaped slot as well as adding a pair of small square parasitic patches at the center of the radiating patch, two separate notched bands for rejecting 5.2 GHz lower WLAN and 5.8 GHz upper WLAN are realized, respectively. Additionally, by integrating the slotted radiation patch with the narrow rectangular ground plane, an enhanced impedance bandwidth can be achieved, especially at the higher band. The antenna consists of linear symmetrical sections only and is easy for fabrication and fine-tuning. The measured results show that the designed antenna provides a wide impedance bandwidth of 150% from 2.12 to 14.80 GHz for VSWR < 2, except for three notched bands of 3.36–4.16, 4.92–5.36, and 5.68–6.0 GHz. Additionally, the antenna exhibits nearly omnidirectional radiation characteristics, low gain at the stopbands, and flat group delay over the whole UWB except at the stopbands. Simulated and experimental results show that the proposed antenna can provide good frequency-domain and time-domain performances at desired UWB frequencies and be an attractive candidate for portable IoT applications. PMID:28208633

An Indoor Positioning Technique Based on a Feed-Forward Artificial Neural Network Using Levenberg-Marquardt Learning Method

NASA Astrophysics Data System (ADS)

Pahlavani, P.; Gholami, A.; Azimi, S.

2017-09-01

This paper presents an indoor positioning technique based on a multi-layer feed-forward (MLFF) artificial neural networks (ANN). Most of the indoor received signal strength (RSS)-based WLAN positioning systems use the fingerprinting technique that can be divided into two phases: the offline (calibration) phase and the online (estimation) phase. In this paper, RSSs were collected for all references points in four directions and two periods of time (Morning and Evening). Hence, RSS readings were sampled at a regular time interval and specific orientation at each reference point. The proposed ANN based model used Levenberg-Marquardt algorithm for learning and fitting the network to the training data. This RSS readings in all references points and the known position of these references points was prepared for training phase of the proposed MLFF neural network. Eventually, the average positioning error for this network using 30% check and validation data was computed approximately 2.20 meter.

An FEC Adaptive Multicast MAC Protocol for Providing Reliability in WLANs

NASA Astrophysics Data System (ADS)

Basalamah, Anas; Sato, Takuro

For wireless multicast applications like multimedia conferencing, voice over IP and video/audio streaming, a reliable transmission of packets within short delivery delay is needed. Moreover, reliability is crucial to the performance of error intolerant applications like file transfer, distributed computing, chat and whiteboard sharing. Forward Error Correction (FEC) is frequently used in wireless multicast to enhance Packet Error Rate (PER) performance, but cannot assure full reliability unless coupled with Automatic Repeat Request forming what is knows as Hybrid-ARQ. While reliable FEC can be deployed at different levels of the protocol stack, it cannot be deployed on the MAC layer of the unreliable IEEE802.11 WLAN due to its inability to exchange ACKs with multiple recipients. In this paper, we propose a Multicast MAC protocol that enhances WLAN reliability by using Adaptive FEC and study it's performance through mathematical analysis and simulation. Our results show that our protocol can deliver high reliability and throughput performance.

SEMICONDUCTOR INTEGRATED CIRCUITS 8.64-11.62 GHz CMOS VCO and divider in a zero-IF 802.11a/b/g WLAN and Bluetooth application

NASA Astrophysics Data System (ADS)

Yu, Sun; Niansong, Mei; Bo, Lu; Yumei, Huang; Zhiliang, Hong

2010-10-01

A fully integrated VCO and divider implemented in SMIC 0.13-μm RFCMOS 1P8M technology with a 1.2 V supply voltage is presented. The frequency of the VCO is tuning from 8.64 to 11.62 GHz while the quadrature LO signals for 802.11a WLAN in 5.8 GHz band or for 802.11b/g WLAN and Bluetooth in 2.4 GHz band can be obtained by a frequency division by 2 or 4, respectively. A 6 bit switched capacitor array is applied for precise tuning of all necessary frequency bands. The testing results show that the VCO has a phase noise of—113 dBc @ 1 MHz offset from the carrier of 5.5 GHz by dividing VCO output by two and the VCO core consumes 3.72 mW. The figure-of-merit for the tuning-range (FOMT) of the VCO is -192.6 dBc/Hz.

Exposure assessment of microwave ovens and impact on total exposure in WLANs

PubMed Central

Plets, David; Verloock, Leen; Van Den Bossche, Matthias; Tanghe, Emmeric; Joseph, Wout; Martens, Luc

2016-01-01

In situ exposure of electric fields of 11 microwave ovens is assessed in an occupational environment and in an office. Measurements as a function of distance without load and with a load of 275 ml of tap water were performed at distances of <1 m. The maximal measured field was 55.2 V m−1 at 5 cm from the oven (without load), which is 2.5 and 1.1 times below the International Commission on Non-Ionizing Radiation Protection reference level for occupational exposure and general public exposure, respectively. For exposure at distances of >1 m, a model of the electric field in a realistic environment is proposed. In an office scenario, switching on a microwave oven increases the median field strength from 91 to 145 mV m−1 (+91 %) in a traditional Wireless Local Area Network (WLAN) deployment and from 44 to 92 mV m−1 (+109 %) in an exposure-optimised WLAN deployment. PMID:25956787

Bandwidth enhancement of monopole antenna with DGS for SHF and reconfigurable structure for WiMAX, WLAN and C-band applications

NASA Astrophysics Data System (ADS)

Beigi, P.; Mohammadi, P.

2017-11-01

In this study a reconfigurable antenna for WiMAX, WLAN, C-bands and SHF applications has been presented. The main body of antenna includes rectangular and L-shaped slotted ground plane and a rectangular patch with slotted feed line, for impedance bandwidth enhancement. In the proposed antenna, a PIN diode is used to adjust the frequency band to SHF, WiMAX, WLAN and C-bands applications. When PIN diode is forward-biased, the antenna covers the 3.5-31 GHz frequency range (i.e. a 160% bandwidth) and when the PIN diode is in its off-state, it operates between 3.4-5.8 GHz. The designed antenna, with a very small size of 12 × 18 × 1.6 mm3, has been fabricated and tested. The radiation pattern is approximately omnidirectional. Simulations and experimental results are in a good agreement with each other and suggest good performance for the presented antenna.

Textile antenna integrated with compact AMC and parasitic elements for WLAN/WBAN applications

NASA Astrophysics Data System (ADS)

Lago, Herwansyah; Soh, Ping Jack; Jamlos, Mohd Faizal; Shohaimi, Nursuriati; Yan, Sen; Vandenbosch, Guy A. E.

2016-12-01

A wearable antenna fully designed and fabricated using textile is presented. Both antenna and artificial magnetic conductor plane are designed for operation in the wireless local area network (WLAN)/wireless body area network (WBAN) band from 2.4 to 2.5 GHz. The AMC unit element is designed based on the rectangular patch structure, which is then integrated using slots and slits for bandwidth broadening. Meanwhile, the combination of the slits and L-shaped parasitic elements applied at four edges of the rectangular antenna structure enabled unidirectional radiation outwards from the body. The structure is coaxially fed using a rectangular ring slot centered on the radiating element. Simulated and measured reflection and radiation performance indicate a satisfactory agreement, fulfilling the requirements for WLAN/WBAN applications both in free space and on body. The shielding effectiveness provided by the AMC plane is also evaluated numerically in terms of specific absorption rate, indicating levels below the European regulatory limit of 2 W/kg.

CMOS analog baseband circuitry for an IEEE 802.11 b/g/n WLAN transceiver

NASA Astrophysics Data System (ADS)

Zheng, Gong; Xiaojie, Chu; Qianqian, Lei; Min, Lin; Yin, Shi

2012-11-01

An analog baseband circuit for a direct conversion wireless local area network (WLAN) transceiver in a standard 0.13-μm CMOS occupying 1.26 mm2 is presented. The circuit consists of active-RC receiver (RX) 4th order elliptic lowpass filters(LPFs), transmit (PGAs) with DC offset cancellation (DCOC) servo loops, and on-chip output buffers. The RX baseband gain can be programmed in the range of -11 to 49 dB in 2 dB steps with 50-30.2 nV/√Hz input referred noise (IRN) and a 21 to -41 dBm in-band 3rd order interception point (IIP3). The RX/TX LPF cutoff frequencies can be switched between 5 MHz, 10 MHz, and 20 MHz to fulfill the multimode 802.11b/g/n requirements. The TX baseband gain of the I/Q paths are tuned separately from -1.6 to 0.9 dB in 0.1 dB steps to calibrate TX I/Q gain mismatches. By using an identical integrator based elliptic filter synthesis method together with global compensation applied to the LPF capacitor array, the power consumption of the RX LPF is considerably reduced and the proposed chip draws 26.8 mA/8 mA by the RX/TX baseband paths from a 1.2 V supply.

Solar-Powered Airplane with Cameras and WLAN

NASA Technical Reports Server (NTRS)

Higgins, Robert G.; Dunagan, Steve E.; Sullivan, Don; Slye, Robert; Brass, James; Leung, Joe G.; Gallmeyer, Bruce; Aoyagi, Michio; Wei, Mei Y.; Herwitz, Stanley R.;

Design of WLAN microstrip antenna for 5.17 - 5.835 GHz

NASA Astrophysics Data System (ADS)

Bugaj, Jarosław; Bugaj, Marek; Wnuk, Marian

2017-04-01

This paper presents the project of miniaturized WLAN Antenna made in microstrip technique working at a frequency of 5.17 - 5.835 GHz in 802.11ac IEEE standard. This dual layer antenna is designed on RT/duroid 5870 ROGERS CORPORATION substrate with dielectric constant 2.33 and thickness of 3.175 mm. The antenna parameters such as return loss, VSWR, gain and directivity are simulated and optimized using commercial computer simulation technology microwave studio (CST MWS). The paper presents the results of discussed numerical analysis.

POTS to broadband ... cable modems.

PubMed

Kabachinski, Jeff

2003-01-01

There have been 3 columns talking about broadband communications and now at the very end when it's time to compare using a telco or cableco, I'm asking does it really matter? So what if I can actually get the whole 30 Mbps with a cable network when the website I'm connecting to is running on an ISDN line at 128 Kbps? Broadband offers a lot more bandwidth than the connections many Internet servers have today. Except for the biggest websites, many servers connect to the Internet with a switched 56-Kbps, ISDN, or fractional T1 line. Even with the big websites, my home network only runs a 10 Mbps Ethernet connection to my cable modem. Maybe it doesn't matter that the cable lines are shared or that I can only get 8 Mbps from an ADSL line. Maybe the ISP that I use has a T1 line connection to the Internet so my new ADSL modem has a fatter pipe than my provider! (See table 1). It all makes me wonder what's in store for us in the future. PC technology has increased exponentially in the last 10 years with super fast processor speeds, hard disks of hundreds of gigabytes, and amazing video and audio. Internet connection speeds have failed to keep the same pace. Instead of hundreds of times better or faster--modem speeds are barely 10 times faster. Broadband connections offer some additional speed but still not comparable growth as broadband connections are still in their infancy. Rather than trying to make use of existing communication paths, maybe we need a massive infrastructure makeover of something new. How about national wireless access points so we can connect anywhere, anytime? To use the latest and fastest wireless technology you will simply need to buy another $9.95 WLAN card or download the latest super slick WLAN compression/encryption software. Perhaps it is time for a massive infra-restructuring. Consider the past massive infrastructure efforts. The telcos needed to put in their wiring infrastructure starting in the 1870s before telephones were useful to the masses. CATV was a minor player in the TV broadcast business before they installed their cabling infrastructure and went national. Even automobiles were fairly useless until roads were paved and the highway infrastructure was built!

Induction of stress volatiles and changes in essential oil content and composition upon microwave exposure in the aromatic plant Ocimum basilicum.

PubMed

Lung, Ildikó; Soran, Maria-Loredana; Opriş, Ocsana; Truşcă, Mihail Radu Cătălin; Niinemets, Ülo; Copolovici, Lucian

2016-11-01

Exposure to sustained low intensity microwaves can constitute a stress for the plants, but its effects on plant secondary chemistry are poorly known. We studied the influence of GSM and WLAN-frequency microwaves on emissions of volatile organic compounds and content of essential oil in the aromatic plant Ocimum basilicum L. hypothesizing that microwave exposure leads to enhanced emissions of stress volatiles and overall greater investment in secondary compounds. Compared to the control plants, microwave irradiation led to decreased emissions of β-pinene, α-phellandrene, bornyl acetate, β-myrcene, α-caryophyllene and benzaldehyde, but increased emissions of eucalyptol, estragole, caryophyllene oxide, and α-bergamotene. The highest increase in emission, 21 times greater compared to control, was observed for caryophyllene oxide. The irradiation resulted in increases in the essential oil content, except for the content of phytol which decreased by 41% in the case of GSM-frequency, and 82% in the case of WLAN-frequency microwave irradiation. The strongest increase in response to WLAN irradiation, >17 times greater, was observed for hexadecane and octane contents. Comparisons of volatile compositions by multivariate analyses demonstrated a clear separation of different irradiance treatments, and according to the changes in the volatile emissions, the WLAN-frequency irradiation represented a more severe stress than the GSM-frequency irradiation. Overall, these results demonstrating important modifications in the emission rates, essential oil content and composition indicate that microwave irradiation influences the quality of herbage of this economically important spice plant. Copyright © 2016 Elsevier B.V. All rights reserved.

Real-time network traffic classification technique for wireless local area networks based on compressed sensing

NASA Astrophysics Data System (ADS)

Balouchestani, Mohammadreza

2017-05-01

Network traffic or data traffic in a Wireless Local Area Network (WLAN) is the amount of network packets moving across a wireless network from each wireless node to another wireless node, which provide the load of sampling in a wireless network. WLAN's Network traffic is the main component for network traffic measurement, network traffic control and simulation. Traffic classification technique is an essential tool for improving the Quality of Service (QoS) in different wireless networks in the complex applications such as local area networks, wireless local area networks, wireless personal area networks, wireless metropolitan area networks, and wide area networks. Network traffic classification is also an essential component in the products for QoS control in different wireless network systems and applications. Classifying network traffic in a WLAN allows to see what kinds of traffic we have in each part of the network, organize the various kinds of network traffic in each path into different classes in each path, and generate network traffic matrix in order to Identify and organize network traffic which is an important key for improving the QoS feature. To achieve effective network traffic classification, Real-time Network Traffic Classification (RNTC) algorithm for WLANs based on Compressed Sensing (CS) is presented in this paper. The fundamental goal of this algorithm is to solve difficult wireless network management problems. The proposed architecture allows reducing False Detection Rate (FDR) to 25% and Packet Delay (PD) to 15 %. The proposed architecture is also increased 10 % accuracy of wireless transmission, which provides a good background for establishing high quality wireless local area networks.

Influence of microwave frequency electromagnetic radiation on terpene emission and content in aromatic plants.

PubMed

Soran, Maria-Loredana; Stan, Manuela; Niinemets, Ülo; Copolovici, Lucian

2014-09-15

Influence of environmental stress factors on both crop and wild plants of nutritional value is an important research topic. The past research has focused on rising temperatures, drought, soil salinity and toxicity, but the potential effects of increased environmental contamination by human-generated electromagnetic radiation on plants have little been studied. Here we studied the influence of microwave irradiation at bands corresponding to wireless router (WLAN) and mobile devices (GSM) on leaf anatomy, essential oil content and volatile emissions in Petroselinum crispum, Apium graveolens and Anethum graveolens. Microwave irradiation resulted in thinner cell walls, smaller chloroplasts and mitochondria, and enhanced emissions of volatile compounds, in particular, monoterpenes and green leaf volatiles (GLV). These effects were stronger for WLAN-frequency microwaves. Essential oil content was enhanced by GSM-frequency microwaves, but the effect of WLAN-frequency microwaves was inhibitory. There was a direct relationship between microwave-induced structural and chemical modifications of the three plant species studied. These data collectively demonstrate that human-generated microwave pollution can potentially constitute a stress to the plants. Copyright © 2014 Elsevier GmbH. All rights reserved.

Influence of microwave frequency electromagnetic radiation on terpene emission and content in aromatic plants

PubMed Central

Soran, Maria-Loredana; Stan, Manuela; Niinemets, Ülo; Copolovici, Lucian

2015-01-01

Influence of environmental stress factors on both crop and wild plants of nutritional value is an important research topic. The past research has focused on rising temperatures, drought, soil salinity and toxicity, but the potential effects of increased environmental contamination by human-generated electromagnetic radiation on plants have little been studied. Here we studied the influence of microwave irradiation at bands corresponding to wireless router (WLAN) and mobile devices (GSM) on leaf anatomy, essential oil content and volatile emissions in Petroselinum crispum, Apium graveolens and Anethum graveolens. Microwave irradiation resulted in thinner cell walls, smaller chloroplasts and mitochondria, and enhanced emissions of volatile compounds, in particular, monoterpenes and green leaf volatiles. These effects were stronger for WLAN-frequency microwaves. Essential oil content was enhanced by GSM-frequency microwaves, but the effect of WLAN-frequency microwaves was inhibitory. There was a direct relationship between microwave-induced structural and chemical modifications of the three plant species studied. These data collectively demonstrate that human-generated microwave pollution can potentially constitute a stress to the plants. PMID:25050479

Dual band monopole antenna for WLAN 2.4/5.2/5.8 with truncated ground

NASA Astrophysics Data System (ADS)

Chandan, Bharti, Gagandeep; Srivastava, Toolika; Rai, B. S.

2018-04-01

A dual-band mono-pole antenna is proposed for Wireless LAN applications. The WLAN band is obtained by cutting a rectangular ring and a circular slot in the radiating patch. The overall dimension of antenna is 17×16.5×0.8 mmł. The frequency bands obtained are 2.38-2.9 GHz and 4.7-6.1 GHz with ≤ - 10 dB return loss which covers WLAN 2.4/5.2/5.8 GHz bands. The behavior of the antenna is analyzed in terms of radiation pattern, peak realized gain, radiation efficiency and surface current density. It has dipole like radiation pattern with gain of 2.33 - 4.31 dBi for lower frequency band and 4.29 - 5.16 dBi for upper frequency band with radiation efficiency of 95-98% and 93-96% respectively. The parametric analysis is carried out to understand the consequence of the various shape parameters and to get an optimum design. The simulation and measurement gave the results having close agreement.

Cyber-physical networking for wireless mesh infrastructures

NASA Astrophysics Data System (ADS)

Mannweiler, C.; Lottermann, C.; Klein, A.; Schneider, J.; Schotten, H. D.

2012-09-01

This paper presents a novel approach for cyber-physical network control. "Cyber-physical" refers to the inclusion of different parameters and information sources, ranging from physical sensors (e.g. energy, temperature, light) to conventional network information (bandwidth, delay, jitter, etc.) to logical data providers (inference systems, user profiles, spectrum usage databases). For a consistent processing, collected data is represented in a uniform way, analyzed, and provided to dedicated network management functions and network services, both internally and, through an according API, to third party services. Specifically, in this work, we outline the design of sophisticated energy management functionalities for a hybrid wireless mesh network (WLAN for both backhaul traffic and access, GSM for access only), disposing of autonomous energy supply, in this case solar power. Energy consumption is optimized under the presumption of fluctuating power availability and considerable storage constraints, thus influencing, among others, handover and routing decisions. Moreover, advanced situation-aware auto-configuration and self-adaptation mechanisms are introduced for an autonomous operation of the network. The overall objective is to deploy a robust wireless access and backbone infrastructure with minimal operational cost and effective, cyber-physical control mechanisms, especially dedicated for rural or developing regions.

Coordinate-Based Clustering Method for Indoor Fingerprinting Localization in Dense Cluttered Environments.

PubMed

Liu, Wen; Fu, Xiao; Deng, Zhongliang

2016-12-02

Indoor positioning technologies has boomed recently because of the growing commercial interest in indoor location-based service (ILBS). Due to the absence of satellite signal in Global Navigation Satellite System (GNSS), various technologies have been proposed for indoor applications. Among them, Wi-Fi fingerprinting has been attracting much interest from researchers because of its pervasive deployment, flexibility and robustness to dense cluttered indoor environments. One challenge, however, is the deployment of Access Points (AP), which would bring a significant influence on the system positioning accuracy. This paper concentrates on WLAN based fingerprinting indoor location by analyzing the AP deployment influence, and studying the advantages of coordinate-based clustering compared to traditional RSS-based clustering. A coordinate-based clustering method for indoor fingerprinting location, named Smallest-Enclosing-Circle-based (SEC), is then proposed aiming at reducing the positioning error lying in the AP deployment and improving robustness to dense cluttered environments. All measurements are conducted in indoor public areas, such as the National Center For the Performing Arts (as Test-bed 1) and the XiDan Joy City (Floors 1 and 2, as Test-bed 2), and results show that SEC clustering algorithm can improve system positioning accuracy by about 32.7% for Test-bed 1, 71.7% for Test-bed 2 Floor 1 and 73.7% for Test-bed 2 Floor 2 compared with traditional RSS-based clustering algorithms such as K-means.

Coordinate-Based Clustering Method for Indoor Fingerprinting Localization in Dense Cluttered Environments

PubMed Central

Liu, Wen; Fu, Xiao; Deng, Zhongliang

2016-01-01

Indoor positioning technologies has boomed recently because of the growing commercial interest in indoor location-based service (ILBS). Due to the absence of satellite signal in Global Navigation Satellite System (GNSS), various technologies have been proposed for indoor applications. Among them, Wi-Fi fingerprinting has been attracting much interest from researchers because of its pervasive deployment, flexibility and robustness to dense cluttered indoor environments. One challenge, however, is the deployment of Access Points (AP), which would bring a significant influence on the system positioning accuracy. This paper concentrates on WLAN based fingerprinting indoor location by analyzing the AP deployment influence, and studying the advantages of coordinate-based clustering compared to traditional RSS-based clustering. A coordinate-based clustering method for indoor fingerprinting location, named Smallest-Enclosing-Circle-based (SEC), is then proposed aiming at reducing the positioning error lying in the AP deployment and improving robustness to dense cluttered environments. All measurements are conducted in indoor public areas, such as the National Center For the Performing Arts (as Test-bed 1) and the XiDan Joy City (Floors 1 and 2, as Test-bed 2), and results show that SEC clustering algorithm can improve system positioning accuracy by about 32.7% for Test-bed 1, 71.7% for Test-bed 2 Floor 1 and 73.7% for Test-bed 2 Floor 2 compared with traditional RSS-based clustering algorithms such as K-means. PMID:27918454

Implicit Block ACK Scheme for IEEE 802.11 WLANs

PubMed Central

Sthapit, Pranesh; Pyun, Jae-Young

2016-01-01

The throughput of IEEE 802.11 standard is significantly bounded by the associated Medium Access Control (MAC) overhead. Because of the overhead, an upper limit exists for throughput, which is bounded, including situations where data rates are extremely high. Therefore, an overhead reduction is necessary to achieve higher throughput. The IEEE 802.11e amendment introduced the block ACK mechanism, to reduce the number of control messages in MAC. Although the block ACK scheme greatly reduces overhead, further improvements are possible. In this letter, we propose an implicit block ACK method that further reduces the overhead associated with IEEE 802.11e’s block ACK scheme. The mathematical analysis results are presented for both the original protocol and the proposed scheme. A performance improvement of greater than 10% was achieved with the proposed implementation.

Improvement in the workflow efficiency of treating non-emergency outpatients by using a WLAN-based real-time location system in a level I trauma center.

PubMed

Stübig, Timo; Suero, Eduardo; Zeckey, Christian; Min, William; Janzen, Laura; Citak, Musa; Krettek, Christian; Hüfner, Tobias; Gaulke, Ralph

2013-01-01

Patient localization can improve workflow in outpatient settings, which might lead to lower costs. The existing wireless local area network (WLAN) architecture in many hospitals opens up the possibility of adopting real-time patient tracking systems for capturing and processing position data; once captured, these data can be linked with clinical patient data. To analyze the effect of a WLAN-based real-time patient localization system for tracking outpatients in our level I trauma center. Outpatients from April to August 2009 were included in the study, which was performed in two different stages. In phase I, patient tracking was performed with the real-time location system, but acquired data were not displayed to the personnel. In phase II tracking, the acquired data were automatically collected and displayed. Total treatment time was the primary outcome parameter. Statistical analysis was performed using multiple linear regression, with the significance level set at 0.05. Covariates included sex, age, type of encounter, prioritization, treatment team, number of residents, and radiographic imaging. 1045 patients were included in our study (540 in phase I and 505 in phase 2). An overall improvement of efficiency, as determined by a significantly decreased total treatment time (23.7%) from phase I to phase II, was noted. Additionally, significantly lower treatment times were noted for phase II patients even when other factors were considered (increased numbers of residents, the addition of imaging diagnostics, and comparison among various localization zones). WLAN-based real-time patient localization systems can reduce process inefficiencies associated with manual patient identification and tracking.

Improvement in the workflow efficiency of treating non-emergency outpatients by using a WLAN-based real-time location system in a level I trauma center

PubMed Central

Stübig, Timo; Suero, Eduardo; Zeckey, Christian; Min, William; Janzen, Laura; Citak, Musa; Krettek, Christian; Hüfner, Tobias; Gaulke, Ralph

2013-01-01

Background Patient localization can improve workflow in outpatient settings, which might lead to lower costs. The existing wireless local area network (WLAN) architecture in many hospitals opens up the possibility of adopting real-time patient tracking systems for capturing and processing position data; once captured, these data can be linked with clinical patient data. Objective To analyze the effect of a WLAN-based real-time patient localization system for tracking outpatients in our level I trauma center. Methods Outpatients from April to August 2009 were included in the study, which was performed in two different stages. In phase I, patient tracking was performed with the real-time location system, but acquired data were not displayed to the personnel. In phase II tracking, the acquired data were automatically collected and displayed. Total treatment time was the primary outcome parameter. Statistical analysis was performed using multiple linear regression, with the significance level set at 0.05. Covariates included sex, age, type of encounter, prioritization, treatment team, number of residents, and radiographic imaging. Results/discussion 1045 patients were included in our study (540 in phase I and 505 in phase 2). An overall improvement of efficiency, as determined by a significantly decreased total treatment time (23.7%) from phase I to phase II, was noted. Additionally, significantly lower treatment times were noted for phase II patients even when other factors were considered (increased numbers of residents, the addition of imaging diagnostics, and comparison among various localization zones). Conclusions WLAN-based real-time patient localization systems can reduce process inefficiencies associated with manual patient identification and tracking. PMID:23676246

Towards smart environments using smart objects.

PubMed

Sedlmayr, Martin; Prokosch, Hans-Ulrich; Münch, Ulli

2011-01-01

Barcodes, RFID, WLAN, Bluetooth and many more technologies are used in hospitals. They are the technological bases for different applications such as patient monitoring, asset management and facility management. However, most of these applications exist side by side with hardly any integration and even interoperability is not guaranteed. Introducing the concept of smart objects inspired by the Internet of Things can improve the situation by separating the capabilities and functions of an object from the implementing technology such as RFID or WLAN. By aligning technological and business developments smart objects have the power to transform a hospital from an agglomeration of technologies into a smart environment.

A Novel Design of Frequency Reconfigurable Antenna for UWB Application

NASA Astrophysics Data System (ADS)

Yang, Xiaolin; Yu, Ziliang; Wu, Zheng; Shen, Huajiao

2016-09-01

In this paper, we present a novel frequency reconfigurable antenna which could be easily operate in a single notched-band (WiMAX (3.3-3.6 GHz)) UWB frequency band, another single notched-band (WLAN (5-6 GHz)) UWB frequency band and the dual band-notched UWB frequency band (the stopband covers the WiMAX (3.3-3.6 GHz) and WLAN (5-6 GHz)). The reconfigurability is achieved by changing the states of PIN diodes. The simulated results are in agreement well with the measured results. And the measured patterns are slightly changed with antenna reconfiguration. The proposed antenna is a good candidate for various UWB applications.

Research of application mode for FTTX technology

NASA Astrophysics Data System (ADS)

Wang, Zhong; Yun, Xiang; Huang, Wei

2009-08-01

With rapid development of Internet and broadband access network, the technologies of xDSL, FTTx+LAN, WLAN have more applications, new network service emerges in endless stream, especially the increase of network game, meeting TV, video on demand, etc. FTTH supports all present and future service with enormous bandwidth, including traditional telecommunication service, traditional data service and traditional TV service, and the future digital TV and VOD. With huge bandwidth of FTTH, it wins the final solution of broadband network, becomes the final goal of development of optical access network. In this paper, technique theory of EPON is introduced at first. At the same time, MAC frame structure, automatic detection and ranging of MPCP, DBA,and multi-LLID of EPON is analyzed. Then, service development ability, cost advantage and maintenance superiority based on EPON technology are carried out. At last,with Cost comparison between FTTH / FTTB building model and the traditional model, FTTB + LAN mode which is suitable for the newadding residential users in general areas and FTTN + DSL mode which is suitable for the old city and rural access network transformation are built up in detail. And FTTN + DSL project of rural information in rural areas and FTTH broadband HOUSE project on service solutions program are analyzed. comparing to the traditional access technologies, EPON technology has the obvious advantages, such as distance transmission, high or wide band, saving line resources, service abilities, etc. These are the qualities which not only be served for home users, but solve more access problems for us effectively.

Indoor Free Space Optic: a new prototype, realization and evaluation

NASA Astrophysics Data System (ADS)

Bouchet, Olivier; Besnard, Pascal; Mihaescu, Adrian

2008-08-01

The Free Space Optic (FSO) communication is a daily reality used by an increasing number of companies. For indoor environment, optical wireless communication becomes a good alternative with respect to radio proposals. For both technologies, the architecture is similar: emission/reception base station (Gateway or Bridge) are installed to cover zones, which are defined to ensure a quality of service. The customers may be connected to the Wireless Local Area Network (WLAN) with an adapter or module that emits and receives on this network. But due to its specific characteristics, wireless optical technology could present important advantages such as: Transmitted data security, medical immunity, high data rate, etc... Nevertheless, the optical system may have a limit on the network management aspect and link budget. The scope of this paper is to present a proposal at crossroads between optical fibre telecom system and data processing. In this document, we will present a prototype developed in Brittany during a regional collaborative project (Techim@ges). In order to answer to the management aspect and the link budget, this prototype uses an optical multiplexing technique in 1550 nm band: the Wavelength Division Multiple Access (WDMA). Moreover it also proposes a new class 1 high power emission solution. This full duplex system transmits these various wavelengths in free space, by using optical Multiplexer/Demultiplexer and optical modules. Each module has a defined and personal wavelength associated to the terminal identification (addresses MAC or IP). This approach permits a data rate at a minimum of a ten's Mbit/s per customer and potentially hundred Mbps for a line of sight system. The application field for the achieved and proposed prototype is potentially investigated from WLAN to WPAN.

Collision Resolution Scheme with Offset for Improved Performance of Heterogeneous WLAN

NASA Astrophysics Data System (ADS)

Upadhyay, Raksha; Vyavahare, Prakash D.; Tokekar, Sanjiv

2016-03-01

CSMA/CA based DCF of 802.11 MAC layer employs best effort delivery model, in which all stations compete for channel access with same priority. Heterogeneous conditions result in unfairness among stations and degradation in throughput, therefore, providing different priorities to different applications for required quality of service in heterogeneous networks is challenging task. This paper proposes a collision resolution scheme with a novel concept of introducing offset, which is suitable for heterogeneous networks. Selection of random value by a station for its contention with offset results in reduced probability of collision. Expression for the optimum value of the offset is also derived. Results show that proposed scheme, when applied to heterogeneous networks, has improved throughput and fairness than conventional scheme. Results show that proposed scheme also exhibits higher throughput and fairness with reduced delay in homogeneous networks.

A highly linear baseband Gm—C filter for WLAN application

NASA Astrophysics Data System (ADS)

Lijun, Yang; Zheng, Gong; Yin, Shi; Zhiming, Chen

2011-09-01

A low voltage, highly linear transconductan—C (Gm—C) low-pass filter for wireless local area network (WLAN) transceiver application is proposed. This transmitter (Tx) filter adopts a 9.8 MHz 3rd-order Chebyshev low pass prototype and achieves 35 dB stop-band attenuation at 30 MHz frequency. By utilizing pseudo-differential linear-region MOS transconductors, the filter IIP3 is measured to be as high as 9.5 dBm. Fabricated in a 0.35 μm standard CMOS technology, the proposed filter chip occupies a 0.41 × 0.17 mm2 die area and consumes 3.36 mA from a 3.3-V power supply.

Indoor Localization Using Wi-Fi Based Fingerprinting and Trilateration Techiques for Lbs Applications

NASA Astrophysics Data System (ADS)

Chan, S.; Sohn, G.

2012-06-01

The past few years have seen wide spread adoption of outdoor positioning services, mainly GPS, being incorporated into everyday devices such as smartphones and tablets. While outdoor positioning has been well received by the public, its indoor counterpart has been mostly limited to private use due to its higher costs and complexity for setting up the proper environment. The objective of this research is to provide an affordable mean for indoor localization using wireless local area network (WLAN) Wi-Fi technology. We combined two different Wi-Fi approaches to locate a user. The first method involves the use of matching the pre-recorded received signal strength (RSS) from nearby access points (AP), to the data transmitted from the user on the fly. This is commonly known as "fingerprint matching". The second approach is a distance-based trilateration approach using three known AP coordinates detected on the user's device to derive the position. The combination of the two steps enhances the accuracy of the user position in an indoor environment allowing location-based services (LBS) such as mobile augmented reality (MAR) to be deployed more effectively in the indoor environment. The mapping of the RSS map can also prove useful to IT planning personnel for covering locations with no Wi-Fi coverage (ie. dead spots). The experiments presented in this research helps provide a foundation for the integration of indoor with outdoor positioning to create a seamless transition experience for users.

A High Speed, Long-Range Mobile Communications Link for use in Polar Regions

NASA Astrophysics Data System (ADS)

Chalishazar, N.; Prescott, G.; Braaten, D.

2003-12-01

The Polar Radar for Ice Sheet Measurements (PRISM) project has developed a high bandwidth, wireless communications link between an autonomous rover and a manned vehicle deployed on a polar ice sheet to exchange real-time video, timing signals for a bistatic radar, and rover sensory data. The PRISM project is developing advanced intelligent remote sensing technology that involves radar systems, an autonomous rover, and communications systems to measure detailed ice sheet characteristics, and to determine bed conditions (frozen or wet) below active ice sheets in both Greenland and Antarctica. While this wireless communications link is being developed to fill a need within the PRISM Project, the same technology will allow polar researchers separated by moderate distances ( ˜10 km) to exchange data. The communications link is based on a high data rate 802.11b wireless technology, and a prototype system has been tested and evaluated during field experiments conducted at the NorthGRIP ice core drilling camp in Greenland (75° 06\\'\\ N, 42° 20\\'\\ W) from June 23-July 17, 2003. The IEEE 802.11b standard works in the 2.4-2.483 GHz band and has been widely used for high-speed data transfer in a WLAN (Wireless Local Area Network). It typically has a range of a few hundred meters and theoretical data rates on the order of 11 Mbps. It has been used for a number of applications in home and office environments. We modified a 802.11b system to operate up to a maximum distance of about 8 km and investigated the radio propagation environment over the flat terrain of the Greenland ice sheet. We evaluated its performance along three different tracks of 8 km in length, and made throughput measurements at intervals of 0.5 km. We measured the received signal strength and noise level in 2-s intervals along these 8 km tracks. Also we conducted experiments for four different antenna heights (1, 2, 3 and 5 m) for developing a radio propagation model for WLAN communication over the ice sheet. We found that peer-to-peer communication between nodes on the ice had data rates varying from 4.5 Mbps at close range to 2.5 Mbps at a distance of 8 km from the base station. The design, propagation model, throughput and coverage of this peer-to-peer communications system in Greenland are presented in this paper. This WLAN system has numerous applications in polar field camps. We tested the transfer of real-time video segments across this link for our educational outreach efforts in the field. These video segments were subsequently uploaded using an Iridium-based Internet link, and sent back to the University of Kansas. The wireless Internet connectivity was also made available to members of the North Grip camp, who were able to access e-mail and the Internet from their tents and common areas. However, throughput for wireless access to the Internet was limited by the Iridium-based Internet connection that had a maximum bandwidth of 9.6 Kbps.

Visual object recognition for mobile tourist information systems

NASA Astrophysics Data System (ADS)

Paletta, Lucas; Fritz, Gerald; Seifert, Christin; Luley, Patrick; Almer, Alexander

2005-03-01

We describe a mobile vision system that is capable of automated object identification using images captured from a PDA or a camera phone. We present a solution for the enabling technology of outdoors vision based object recognition that will extend state-of-the-art location and context aware services towards object based awareness in urban environments. In the proposed application scenario, tourist pedestrians are equipped with GPS, W-LAN and a camera attached to a PDA or a camera phone. They are interested whether their field of view contains tourist sights that would point to more detailed information. Multimedia type data about related history, the architecture, or other related cultural context of historic or artistic relevance might be explored by a mobile user who is intending to learn within the urban environment. Learning from ambient cues is in this way achieved by pointing the device towards the urban sight, capturing an image, and consequently getting information about the object on site and within the focus of attention, i.e., the users current field of view.

Design of modified pentagonal patch antenna on defective ground for Wi-Max/WLAN application

NASA Astrophysics Data System (ADS)

Rawat, Sanyog; Sharma, K. K.

2016-04-01

This paper presents the design and performance of a modified pentagonal patch antenna with defective ground plane. A pentagonal slot is inserted in the pentagonal patch and slot loaded ground through optimized dimensions is used in the antenna to resonate it at dual frequency. The geometry operates at two resonant frequencies (2.5 GHz and 5.58 GHz) and offers impedance bandwidth of 864 MHz and 554 MHz in the two bands of interest. The proposed antenna covers the lower band (2.45 to 2.484/2.495 to 2.695 GHz) and upper band (5.15 to 5.825 GHz/5.25 to 5.85 GHz) allocated for Wi-Max and WLAN communication systems.

A reconfigurable frequency-selective surface for dual-mode multi-band filtering applications

NASA Astrophysics Data System (ADS)

Majidzadeh, Maryam; Ghobadi, Changiz; Nourinia, Javad

2017-03-01

A reconfigurable single-layer frequency-selective surface (FSS) with dual-mode multi-band modes of operation is presented. The proposed structure is printed on a compact 10 × 10 mm2 FR4 substrate with the thickness of 1.6 mm. A simple square loop is printed on the front side while another one along with two defected vertical arms is deployed on the backside. To realise the reconfiguration, two pin diodes are embedded on the backside square loop. Suitable insertion of conductive elements along with pin diodes yields in dual-mode multi-band rejection of applicable in service frequency ranges. The first operating mode due to diodes' 'ON' state provides rejection of 2.4 GHz WLAN in 2-3 GHz, 5.2/5.8 GHz WLAN and X band in 5-12 GHz, and a part of Ku band in 13.9-16 GHz. In diodes 'OFF' state, the FSS blocks WLAN in 4-7.3 GHz, X band in 8-12.7 GHz as well as part of Ku band in 13.7-16.7 GHz. As well, high attenuation of incident waves is observed by a high shielding effectiveness (SE) in the blocked frequency bands. Also, a stable behaviour against different polarisations and angles of incidence is obtained. Comprehensive studies are conducted on a fabricated prototype to assess its performance from which encouraging results are obtained.

Design control system of telescope force actuators based on WLAN

NASA Astrophysics Data System (ADS)

Shuai, Xiaoying; Zhang, Zhenchao

2010-05-01

With the development of the technology of autocontrol, telescope, computer, network and communication, the control system of the modern large and extra lager telescope become more and more complicated, especially application of active optics. Large telescope based on active optics maybe contain enormous force actuators. This is a challenge to traditional control system based on wired networks, which result in difficult-to-manage, occupy signification space and lack of system flexibility. Wireless network can resolve these disadvantages of wired network. Presented control system of telescope force actuators based on WLAN (WFCS), designed the control system framework of WFCS. To improve the performance of real-time, we developed software of force actuators control system in Linux. Finally, this paper discussed improvement of WFCS real-time, conceived maybe improvement in the future.

Spectrum sharing between a surveillance radar and secondary Wi-Fi networks

NASA Astrophysics Data System (ADS)

Hessar, Farzad; Roy, Sumit

2016-06-01

Co-existence between unlicensed networks that share spectrum spatio-temporally with terrestrial (e.g. Air Traffic Control) and shipborne radars in 3-GHz band is attracting significant interest. Similar to every primary-secondary coexistence scenario, interference from unlicensed devices to a primary receiver must be within acceptable bounds. In this work, we formulate the spectrum sharing problem between a pulsed, search radar (primary) and 802.11 WLAN as the secondary. We compute the protection region for such a search radar for a) a single secondary user (initially) as well as b) a random spatial distribution of multiple secondary users. Furthermore, we also analyze the interference to the WiFi devices from the radar's transmissions to estimate the impact on achievable WLAN throughput as a function of distance to the primary radar.

Wideband dual frequency modified ellipse shaped patch antenna for WLAN/Wi-MAX/UWB application

NASA Astrophysics Data System (ADS)

Jain, P. K.; Jangid, K. G.; R. Sharma, B.; Saxena, V. K.; Bhatnagar, D.

2018-05-01

This paper communicates the design and performance of microstrip line fed modified ellipses shaped radiating patch with defected ground structure. Wide impedance bandwidth performance is achieved by applying a pentagonal slot and T slot structure in ground plane. By inserting two semi ellipses shaped ring in ground, we obtained axial ratio bandwidth approx 600 MHz. The proposed antenna is simulated by utilizing CST Microwave Studio simulator 2014. This antenna furnishes wide impedance bandwidth approx. 4.23 GHz, which has spread into two bands 2.45 GHz - 5.73 GHz and 7.22 GHz - 8.17 GHz with nearly flat gain in operating frequency range. This antenna may be proved as a practicable structure for modern wireless communication systems including Wi-MAX, WLAN and lower band of UWB.

Dual band multi frequency rectangular patch microstrip antenna with flyswatter shaped slot for wireless systems

NASA Astrophysics Data System (ADS)

Bhardwaj, Dheeraj; Saraswat, Shriti; Gulati, Gitansh; Shekhar, Snehanshu; Joshi, Kanika; Sharma, Komal

2016-03-01

In this paper a dual band planar antenna has been proposed for IEEE 802.16 Wi-MAX /IEEE 802.11 WLAN/4.9 GHz public safety applications. The antenna comprises a frequency bandwidth of 560MHz (3.37GHz-3.93GHz) for WLAN and WiMAX and 372MHz (4.82GHz-5.192GHz) for 4.9 GHz public safety applications and Radio astronomy services (4.8-4.94 GHz). The proposed antenna constitutes of a single microstrip patch reactively loaded with three identical steps positioned in a zig-zag manner towards the radiating edges of the patch. The coaxially fed patch antenna characteristics (radiation pattern, antenna gain, antenna directivity, current distribution, S11) have been investigated. The antenna design is primarily focused on achieving a dual band operation.

Coexistence issues for a 2.4 GHz wireless audio streaming in presence of bluetooth paging and WLAN

NASA Astrophysics Data System (ADS)

Pfeiffer, F.; Rashwan, M.; Biebl, E.; Napholz, B.

2015-11-01

Nowadays, customers expect to integrate their mobile electronic devices (smartphones and laptops) in a vehicle to form a wireless network. Typically, IEEE 802.11 is used to provide a high-speed wireless local area network (WLAN) and Bluetooth is used for cable replacement applications in a wireless personal area network (PAN). In addition, Daimler uses KLEER as third wireless technology in the unlicensed (UL) 2.4 GHz-ISM-band to transmit full CD-quality digital audio. As Bluetooth, IEEE 802.11 and KLEER are operating in the same frequency band, it has to be ensured that all three technologies can be used simultaneously without interference. In this paper, we focus on the impact of Bluetooth and IEEE 802.11 as interferer in presence of a KLEER audio transmission.

Drahtlose Audioübertragung

NASA Astrophysics Data System (ADS)

Niehoff, Wolfgang

Für die drahtlose Übertragung von Audiosignalen werden elektromagnetische Wellen als Trägersignale genutzt. Auch der Rundfunk bedient sich dieser Wellen auf unterschiedlichen Frequenzen, ebenso Kommunikationsdienste wie der Mobilfunk, WLAN, Bluetooth und andere Funkdienste (Abb. 19.1).

Radiation Pattern of Chair Armed Microstrip Antenna

NASA Astrophysics Data System (ADS)

Mishra, Rabindra Kishore; Sahu, Kumar Satyabrat

2016-12-01

This work analyzes planar antenna conformable to chair arm shaped surfaces for WLAN application. Closed form expressions for its radiation pattern are developed and validated using measurements on prototype and commercial EM code at 2.4 GHz.

Dual band multi frequency rectangular patch microstrip antenna with flyswatter shaped slot for wireless systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhardwaj, Dheeraj, E-mail: dbhardwaj.bit@gmail.com; Saraswat, Shriti, E-mail: saraswat.srishti@gmail.com; Gulati, Gitansh, E-mail: gitanshgulati@gmail.com

In this paper a dual band planar antenna has been proposed for IEEE 802.16 Wi-MAX /IEEE 802.11 WLAN/4.9 GHz public safety applications. The antenna comprises a frequency bandwidth of 560MHz (3.37GHz-3.93GHz) for WLAN and WiMAX and 372MHz (4.82GHz-5.192GHz) for 4.9 GHz public safety applications and Radio astronomy services (4.8-4.94 GHz). The proposed antenna constitutes of a single microstrip patch reactively loaded with three identical steps positioned in a zig-zag manner towards the radiating edges of the patch. The coaxially fed patch antenna characteristics (radiation pattern, antenna gain, antenna directivity, current distribution, S{sub 11}) have been investigated. The antenna design is primarily focused onmore » achieving a dual band operation.« less

Digital FMCW for ultrawideband spectrum sensing

NASA Astrophysics Data System (ADS)

Cheema, A. A.; Salous, S.

2016-08-01

An ultrawideband digital frequency-modulated continuous wave sensing engine is proposed as an alternative technique for cognitive radio applications. A dual-band demonstrator capable of sensing 750 MHz bandwidth in 204.8 µs is presented. Its performance is illustrated from both bench tests and from real-time measurements of the GSM 900 band and the 2.4 GHz wireless local area network (WLAN) band. The measured sensitivity and noise figure values are -90 dBm for a signal-to-noise ratio margin of at least 10 dB and ~13-14 dB, respectively. Data were collected over 24 h and were analyzed by using the energy detection method. The obtained results show the time variability of occupancy, and considerable sections of the spectrum are unoccupied. In addition, unlike the cyclic temporal variations of spectrum occupancy in the GSM 900 band, the detected variations in the 2.4 GHz WLAN band have an impulsive nature.

Design of an ultra low power third order continuous time current mode ΣΔ modulator for WLAN applications.

PubMed

Behzadi, Kobra; Baghelani, Masoud

2014-05-01

This paper presents a third order continuous time current mode ΣΔ modulator for WLAN 802.11b standard applications. The proposed circuit utilized feedback architecture with scaled and optimized DAC coefficients. At circuit level, we propose a modified cascade current mirror integrator with reduced input impedance which results in more bandwidth and linearity and hence improves the dynamic range. Also, a very fast and precise novel dynamic latch based current comparator is introduced with low power consumption. This ultra fast comparator facilitates increasing the sampling rate toward GHz frequencies. The modulator exhibits dynamic range of more than 60 dB for 20 MHz signal bandwidth and OSR of 10 while consuming only 914 μW from 1.8 V power supply. The FoM of the modulator is calculated from two different methods, and excellent performance is achieved for proposed modulator.

Design of an ultra low power third order continuous time current mode ΣΔ modulator for WLAN applications

PubMed Central

Behzadi, Kobra; Baghelani, Masoud

2013-01-01

This paper presents a third order continuous time current mode ΣΔ modulator for WLAN 802.11b standard applications. The proposed circuit utilized feedback architecture with scaled and optimized DAC coefficients. At circuit level, we propose a modified cascade current mirror integrator with reduced input impedance which results in more bandwidth and linearity and hence improves the dynamic range. Also, a very fast and precise novel dynamic latch based current comparator is introduced with low power consumption. This ultra fast comparator facilitates increasing the sampling rate toward GHz frequencies. The modulator exhibits dynamic range of more than 60 dB for 20 MHz signal bandwidth and OSR of 10 while consuming only 914 μW from 1.8 V power supply. The FoM of the modulator is calculated from two different methods, and excellent performance is achieved for proposed modulator. PMID:25685504

PKI-based secure mobile access to electronic health services and data.

PubMed

Kambourakis, G; Maglogiannis, I; Rouskas, A

2005-01-01

Recent research works examine the potential employment of public-key cryptography schemes in e-health environments. In such systems, where a Public Key Infrastructure (PKI) is established beforehand, Attribute Certificates (ACs) and public key enabled protocols like TLS, can provide the appropriate mechanisms to effectively support authentication, authorization and confidentiality services. In other words, mutual trust and secure communications between all the stakeholders, namely physicians, patients and e-health service providers, can be successfully established and maintained. Furthermore, as the recently introduced mobile devices with access to computer-based patient record systems are expanding, the need of physicians and nurses to interact increasingly with such systems arises. Considering public key infrastructure requirements for mobile online health networks, this paper discusses the potential use of Attribute Certificates (ACs) in an anticipated trust model. Typical trust interactions among doctors, patients and e-health providers are presented, indicating that resourceful security mechanisms and trust control can be obtained and implemented. The application of attribute certificates to support medical mobile service provision along with the utilization of the de-facto TLS protocol to offer competent confidentiality and authorization services is also presented and evaluated through experimentation, using both the 802.11 WLAN and General Packet Radio Service (GPRS) networks.

A Microstrip Patch-Fed Short Backfire Antenna for the Tracking and Data Relay Satellite System-Continuation (TDRSS-C) Multiple Access (MA) Array

NASA Technical Reports Server (NTRS)

Nessel, James A.; Kory, Carol L.; Lambert, Kevin M.; Acosta, Roberto J.

2006-01-01

Short Backfire Antennas (SBAs) are widely utilized for mobile satellite communications, tracking, telemetry, and wireless local area network (WLAN) applications due to their compact structure and excellent radiation characteristics [1-3]. Typically, these SBA s consist of an excitation element (i.e., a half-wavelength dipole), a reflective bottom plane, a planar sub-reflector located above the "exciter", and an outer circular rim. This configuration is capable of achieving gains on the order of 13-15 dBi, but with relatively narrow bandwidths (approx.3%-5%), making it incompatible with the requirements of the next generation enhanced Tracking and Data Relay Satellite System-Continuation (TDRSS-C) Multiple Access (MA) array [1]. Several attempts have been made to enhance the bandwidth performance of the common dipole-fed SBA by employing various other feeding mechanisms (e.g., waveguide, slot) with moderate success [4-5]. In this paper, a novel method of using a microstrip patch is employed for the first time to excite an SBA. The patch element is fed via two H-shaped slots electromagnetically coupled to a broadband hybrid coupler to maintain a wide bandwidth, as well as provide for dual circular polarization capabilities.

Scalable Video Streaming Relay for Smart Mobile Devices in Wireless Networks

PubMed Central

Kwon, Dongwoo; Je, Huigwang; Kim, Hyeonwoo; Ju, Hongtaek; An, Donghyeok

2016-01-01

Recently, smart mobile devices and wireless communication technologies such as WiFi, third generation (3G), and long-term evolution (LTE) have been rapidly deployed. Many smart mobile device users can access the Internet wirelessly, which has increased mobile traffic. In 2014, more than half of the mobile traffic around the world was devoted to satisfying the increased demand for the video streaming. In this paper, we propose a scalable video streaming relay scheme. Because many collisions degrade the scalability of video streaming, we first separate networks to prevent excessive contention between devices. In addition, the member device controls the video download rate in order to adapt to video playback. If the data are sufficiently buffered, the member device stops the download. If not, it requests additional video data. We implemented apps to evaluate the proposed scheme and conducted experiments with smart mobile devices. The results showed that our scheme improves the scalability of video streaming in a wireless local area network (WLAN). PMID:27907113

Scalable Video Streaming Relay for Smart Mobile Devices in Wireless Networks.

PubMed

Kwon, Dongwoo; Je, Huigwang; Kim, Hyeonwoo; Ju, Hongtaek; An, Donghyeok

2016-01-01

Recently, smart mobile devices and wireless communication technologies such as WiFi, third generation (3G), and long-term evolution (LTE) have been rapidly deployed. Many smart mobile device users can access the Internet wirelessly, which has increased mobile traffic. In 2014, more than half of the mobile traffic around the world was devoted to satisfying the increased demand for the video streaming. In this paper, we propose a scalable video streaming relay scheme. Because many collisions degrade the scalability of video streaming, we first separate networks to prevent excessive contention between devices. In addition, the member device controls the video download rate in order to adapt to video playback. If the data are sufficiently buffered, the member device stops the download. If not, it requests additional video data. We implemented apps to evaluate the proposed scheme and conducted experiments with smart mobile devices. The results showed that our scheme improves the scalability of video streaming in a wireless local area network (WLAN).

Network architecture for global biomedical monitoring service.

PubMed

Lopez-Casado, Carmen; Tejero-Calado, Juan; Bernal-Martin, Antonio; Lopez-Gomez, Miguel; Romero-Romero, Marco; Quesada, Guillermo; Lorca, Julio; Garcia, Eugenia

2005-01-01

Most of the patients who are in hospitals and, increasingly, patients controlled remotely from their homes, at-home monitoring, are continuously monitored in order to control their evolution. The medical devices used up to now, force the sanitary staff to go to the patients' room to control the biosignals that are being monitored, although in many cases, patients are in perfect conditions. If patient is at home, it is he or she who has to go to the hospital to take the record of the monitored signal. New wireless technologies, such as BlueTooth and WLAN, make possible the deployment of systems that allow the display and storage of those signals in any place where the hospital intranet is accessible. In that way, unnecessary displacements are avoided. This paper presents a network architecture that allows the identification of the biosignal acquisition device as IP network nodes. The system is based on a TCP/IP architecture which is scalable and avoids the deployment of a specific purpose network.

Design of UWB Monopole Antenna with Dual Notched Bands Using One Modified Electromagnetic-Bandgap Structure

PubMed Central

Xu, Ziqiang

2013-01-01

A modified electromagnetic-bandgap (M-EBG) structure and its application to planar monopole ultra-wideband (UWB) antenna are presented. The proposed M-EBG which comprises two strip patch and an edge-located via can perform dual notched bands. By properly designing and placing strip patch near the feedline, the proposed M-EBG not only possesses a simple structure and compact size but also exhibits good band rejection. Moreover, it is easy to tune the dual notched bands by altering the dimensions of the M-EBG. A demonstration antenna with dual band-notched characteristics is designed and fabricated to validate the proposed method. The results show that the proposed antenna can satisfy the requirements of VSWR < 2 over UWB 3.1–10.6 GHz, except for the rejected bands of the world interoperability for microwave access (WiMAX) and the wireless local area network (WLAN) at 3.5 GHz and 5.5 GHz, respectively. PMID:24170984

New approach to enhance and evaluate the performance of vehicle-infrastructure integration and its communication systems, final report.

DOT National Transportation Integrated Search

2010-09-01

Initial research studied the use of wireless local area networks (WLAN) protocols in Inter-Vehicle Communications : (IVC) environments. The protocols performance was evaluated in terms of measuring throughput, jitter time and : delay time. This re...

Physical layer simulation study for the coexistence of WLAN standards

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howlader, M. K.; Keiger, C.; Ewing, P. D.

This paper presents the results of a study on the performance of wireless local area network (WLAN) devices in the presence of interference from other wireless devices. To understand the coexistence of these wireless protocols, simplified physical-layer-system models were developed for the Bluetooth, Wireless Fidelity (WiFi), and Zigbee devices, all of which operate within the 2.4-GHz frequency band. The performances of these protocols were evaluated using Monte-Carlo simulations under various interference and channel conditions. The channel models considered were basic additive white Gaussian noise (AWGN), Rayleigh fading, and site-specific fading. The study also incorporated the basic modulation schemes, multiple accessmore » techniques, and channel allocations of the three protocols. This research is helping the U.S. Nuclear Regulatory Commission (NRC) understand the coexistence issues associated with deploying wireless devices and could prove useful in the development of a technical basis for guidance to address safety-related issues with the implementation of wireless systems in nuclear facilities. (authors)« less

Portable Integrated Wireless Device Threat Assessment to Aircraft Radio Systems

NASA Technical Reports Server (NTRS)

Salud, Maria Theresa P.; Williams, Reuben A. (Technical Monitor)

2004-01-01

An assessment was conducted on multiple wireless local area network (WLAN) devices using the three wireless standards for spurious radiated emissions to determine their threat to aircraft radio navigation systems. The measurement process, data and analysis are provided for devices tested using IEEE 802.11a, IEEE 802.11b, and Bluetooth as well as data from portable laptops/tablet PCs and PDAs (grouping known as PEDs). A comparison was made between wireless LAN devices and portable electronic devices. Spurious radiated emissions were investigated in the radio frequency bands for the following aircraft systems: Instrument Landing System Localizer and Glideslope, Very High Frequency (VHF) Communication, VHF Omnidirectional Range, Traffic Collision Avoidance System, Air Traffic Control Radar Beacon System, Microwave Landing System and Global Positioning System. Since several of the contiguous navigation systems were grouped under one encompassing measurement frequency band, there were five measurement frequency bands where spurious radiated emissions data were collected for the PEDs and WLAN devices. The report also provides a comparison between emissions data and regulatory emission limit.

Reconfigurable antenna options for 2.45/5 GHz wireless body area networks in healthcare applications.

PubMed

Abbas, Syed Muzahir; Ranga, Yogesh; Esselle, Karu P

2015-01-01

This paper presents electronically reconfigurable antenna options in healthcare applications. They are suitable for wireless body area network devices operating in the industrial, scientific, and medical (ISM) band at 2.45 GHz and IEEE 802.11 Wireless Local Area Network (WLAN) band at 5 GHz (5.15-5.35 GHz, 5.25-5.35 GHz). Two types of antennas are investigated: Antenna-I has a full ground plane and Antenna-II has a partial ground plane. The proposed antennas provide ISM operation in one mode while in another mode they support 5 GHz WLAN band. Their performance is assessed for body centric wireless communication using a simplified human body model. Antenna sensitivity to the gap between the antenna and the human body is investigated for both modes of each antenna. The proposed antennas exhibit a wide radiation pattern along the body surface to provide wide coverage and their small width (14 mm) makes them suitable for on-body communication in healthcare applications.

Cross-Layer Adaptive Feedback Scheduling of Wireless Control Systems

PubMed Central

Xia, Feng; Ma, Longhua; Peng, Chen; Sun, Youxian; Dong, Jinxiang

2008-01-01

There is a trend towards using wireless technologies in networked control systems. However, the adverse properties of the radio channels make it difficult to design and implement control systems in wireless environments. To attack the uncertainty in available communication resources in wireless control systems closed over WLAN, a cross-layer adaptive feedback scheduling (CLAFS) scheme is developed, which takes advantage of the co-design of control and wireless communications. By exploiting cross-layer design, CLAFS adjusts the sampling periods of control systems at the application layer based on information about deadline miss ratio and transmission rate from the physical layer. Within the framework of feedback scheduling, the control performance is maximized through controlling the deadline miss ratio. Key design parameters of the feedback scheduler are adapted to dynamic changes in the channel condition. An event-driven invocation mechanism for the feedback scheduler is also developed. Simulation results show that the proposed approach is efficient in dealing with channel capacity variations and noise interference, thus providing an enabling technology for control over WLAN. PMID:27879934

Wireless Tactical Networks in Support of Undersea Research

DTIC Science & Technology

2001-04-01

of 802.11 is to provide a radio capable of transmitting voice, video, and data standard set of operational rules so that WLAN products between its...networking in support of the network-centric [TFB-99] Trangeled A., Franchi P., Berni A., Data warfare concept, in which operational advantage is

RACOON: a multiuser QoS design for mobile wireless body area networks.

PubMed

Cheng, Shihheng; Huang, Chingyao; Tu, Chun Chen

2011-10-01

In this study, Random Contention-based Resource Allocation (RACOON) medium access control (MAC) protocol is proposed to support the quality of service (QoS) for multi-user mobile wireless body area networks (WBANs). Different from existing QoS designs that focus on a single WBAN, a multiuser WBAN QoS should further consider both inter-WBAN interference and inter-WBAN priorities. Similar problems have been studied in both overlapped wireless local area networks (WLANs) and Bluetooth piconets that need QoS supports. However, these solutions are designed for non-medical transmissions that do not consider any priority scheme for medical applications. Most importantly, these studies focus on only static or low mobility networks. Network mobility of WBANs will introduce unnecessary inter-network collisions and energy waste, which are not considered by these solutions. The proposed multiuser-QoS protocol, RACOON, simultaneously satisfies the inter WBAN QoS requirements and overcomes the performance degradation caused by WBAN mobility. Simulation results verify that RACOON provides better latency and energy control, as compared with WBAN QoS protocols without considering the inter-WBAN requirements.

Hardware platform for multiple mobile robots

NASA Astrophysics Data System (ADS)

Parzhuber, Otto; Dolinsky, D.

2004-12-01

This work is concerned with software and communications architectures that might facilitate the operation of several mobile robots. The vehicles should be remotely piloted or tele-operated via a wireless link between the operator and the vehicles. The wireless link will carry control commands from the operator to the vehicle, telemetry data from the vehicle back to the operator and frequently also a real-time video stream from an on board camera. For autonomous driving the link will carry commands and data between the vehicles. For this purpose we have developed a hardware platform which consists of a powerful microprocessor, different sensors, stereo- camera and Wireless Local Area Network (WLAN) for communication. The adoption of IEEE802.11 standard for the physical and access layer protocols allow a straightforward integration with the internet protocols TCP/IP. For the inspection of the environment the robots are equipped with a wide variety of sensors like ultrasonic, infrared proximity sensors and a small inertial measurement unit. Stereo cameras give the feasibility of the detection of obstacles, measurement of distance and creation of a map of the room.

Building the Wireless Campus

ERIC Educational Resources Information Center

Gerraughty, James F.; Shanafelt, Michael E.

2005-01-01

This prototype is a continuation of a series of wireless prototypes which began in August 2001 and was reported on again in August 2002. This is the final year of this prototype. This continuation allowed Saint Francis University's Center of Excellence for Remote and Medically Under-Served Areas (CERMUSA) to refine the existing WLAN for the Saint…

Using Technology to Enhance Science Inquiry in an Outdoor Classroom

ERIC Educational Resources Information Center

Cantrell, Pamela; Knudson, Mark S.

2006-01-01

Participants in a science professional development field experience were surveyed for their perceptions of the impacts of integrating a wireless local area network (WLAN), pocket PCs, and laptops as tools for enhancing science inquiry. Pocket PCs and laptops were used for data collection and analysis and for communication of research results to…

The Role of Wireless Computing Technology in the Design of Schools.

ERIC Educational Resources Information Center

Nair, Prakash

This document discusses integrating computers logically and affordably into a school building's infrastructure through the use of wireless technology. It begins by discussing why wireless networks using mobile computers are preferable to desktop machines in each classoom. It then explains the features of a wireless local area network (WLAN) and…

WLAN Positioning Methods and Supporting Learning Technologies for Mobile Platforms

ERIC Educational Resources Information Center

Melkonyan, Arsen

2013-01-01

Location technologies constitute an essential component of systems design for autonomous operations and control. The Global Positioning System (GPS) works well in outdoor areas, but the satellite signals are not strong enough to penetrate inside most indoor environments. As a result, a new strain of indoor positioning technologies that make use of…

Symmetric/Asymmetrical SIRs Dual-Band BPF Design for WLAN Applications

NASA Astrophysics Data System (ADS)

Ho, Min-Hua; Ho, Hao-Hung; Chen, Mingchih

This paper presents the dual-band bandpass filters (BPFs) design composed of λ/2 and symmetrically/asymmetrically paired λ/4 stepped impedance resonators (SIRs) for the WLAN applications. The filters cover both the operating frequencies of 2.45 and 5.2GHz. The dual-coupling mechanism is used in the filter design to provide alternative routes for signals of selected frequencies. A prototype filter is composed of λ/2 and symmetrical λ/4 SIRs. The enhanced wide-stopband filter is then developed from the filter with the symmetrical λ/4 SIRs replaced by the asymmetrical ones. The asymmetrical λ/4 SIRs have their higher resonances frequencies isolated from the adjacent I/O SIRs and extend the enhanced filter an upper stopband limit beyond ten time the fundamental frequency. Also, the filter might possess a cross-coupling structure which introduces transmission zeros by the passband edges to improve the signal selectivity. The tapped-line feed is adopted in this circuit to create additional attenuation poles for improving the stopband rejection levels. Experiments are conducted to verify the circuit performance.

Neighbor Discovery Algorithm in Wireless Local Area Networks Using Multi-beam Directional Antennas

NASA Astrophysics Data System (ADS)

Wang, Jin; Peng, Wei; Liu, Song

2017-10-01

Neighbor discovery is an important step for Wireless Local Area Networks (WLAN) and the use of multi-beam directional antennas can greatly improve the network performance. However, most neighbor discovery algorithms in WLAN, based on multi-beam directional antennas, can only work effectively in synchronous system but not in asynchro-nous system. And collisions at AP remain a bottleneck for neighbor discovery. In this paper, we propose two asynchrono-us neighbor discovery algorithms: asynchronous hierarchical scanning (AHS) and asynchronous directional scanning (ADS) algorithm. Both of them are based on three-way handshaking mechanism. AHS and ADS reduce collisions at AP to have a good performance in a hierarchical way and directional way respectively. In the end, the performance of the AHS and ADS are tested on OMNeT++. Moreover, it is analyzed that different application scenarios and the factors how to affect the performance of these algorithms. The simulation results show that AHS is suitable for the densely populated scenes around AP while ADS is suitable for that most of the neighborhood nodes are far from AP.

Microwave energy harvesting based on metamaterial absorbers with multi-layered square split rings for wireless communications

NASA Astrophysics Data System (ADS)

Karaaslan, Muharrem; Bağmancı, Mehmet; Ünal, Emin; Akgol, Oguzhan; Sabah, Cumali

2017-06-01

We propose the design of a multiband absorber based on multi-layered square split ring (MSSR) structure. The multi-layered metamaterial structure is designed to be used in the frequency bands such as WIMAX, WLAN and satellite communication region. The absorption levels of the proposed structure are higher than 90% for all resonance frequencies. In addition, the incident angle and polarization dependence of the multi-layered metamaterial absorber and harvester is also investigated and it is observed that the structure has polarization angle independent frequency response with good absorption characteristics in the entire working frequency band. The energy harvesting ratios of the structure is investigated especially for the resonance frequencies at which the maximum absorption occurs. The energy harvesting potential of the proposed MSSRs is as good as those of the structures given in the literature. Therefore, the suggested design having good absorption, polarization and angle independent characteristics with a wide bandwidth is a potential candidate for future energy harvesting applications in commonly used wireless communication bands, namely WIMAX, WLAN and satellite communication bands.

Design and implementation of low profile antenna for dual-band applications using rotated e-shaped conductor-backed plane.

PubMed

Jalali, Mahdi; Sedghi, Tohid; Shafei, Shahin

2014-01-01

A novel configuration of a printed monopole antenna with a very compact size for satisfying WLAN operations at the 5.2/5.8 GHz and also for X-band operations at the 10 GHz has been proposed. The antenna includes a simple square-shaped patch as the radiator, the rotated U-shaped conductor back plane element with embedded strip on it, and the partial rectangular ground surface. By using the rotated U-shaped conductor-backed plane with proper values, good impedance matching and improvement in bandwidth can be achieved, at the lower and upper bands. The impedance bandwidth for S11 < -10 dB is about 1.15 GHz for 5 GHz band and 5.3 GHz for X-band. The measured peak gains are about 1.9 dBi at WLAN-band and 4.2 dBi at X-band. The experimental results represent that the realized antenna with good omnidirectional radiation characteristics, enough impedance bandwidth, and reasonable gains can be appropriate for various applications of the future developed technologies and handheld devices.

A Very Compact and Low Profile UWB Planar Antenna with WLAN Band Rejection.

PubMed

Syed, Avez; Aldhaheri, Rabah W

2016-01-01

A low-cost coplanar waveguide fed compact ultrawideband (UWB) antenna with band rejection characteristics for wireless local area network (WLAN) is proposed. The notch band characteristic is achieved by etching half wavelength C-shaped annular ring slot in the radiating patch. By properly choosing the radius and position of the slot, the notch band can be adjusted and controlled. With an overall size of 18.7 mm × 17.6 mm, the antenna turns out to be one of the smallest UWB antennas with band-notched characteristics. It has a wide fractional bandwidth of 130% (2.9-13.7 GHz) with VSWR < 2 and rejecting IEEE 802.11a and HIPERLAN/2 frequency band of 5.1-5.9 GHz. Stable omnidirectional radiation patterns in the H plane with an average gain of 4.4 dBi are obtained. The band-notch mechanism of the proposed antenna is examined by HFSS simulator. A good agreement is found between measured and simulated results indicating that the proposed antenna is well suited for integration into portable devices for UWB applications.

Communication latencies of Apple push notification messages relevant for delivery of time-critical information to anesthesia providers.

PubMed

Rothman, Brian S; Dexter, Franklin; Epstein, Richard H

2013-08-01

Tablet computers and smart phones have gained popularity in anesthesia departments for educational and patient care purposes. VigiVU(™) is an iOS application developed at Vanderbilt University for remote viewing of perioperative information, including text message notifications delivered via the Apple Push Notification (APN) service. In this study, we assessed the reliability of the APN service. Custom software was written to send a message every minute to iOS devices (iPad(®), iPod Touch(®), and iPhone(®)) via wireless local area network (WLAN) and cellular pathways 24 hours a day over a 4-month period. Transmission and receipt times were recorded and batched by days, with latencies calculated as their differences. The mean, SEM, and the exact 95% upper confidence limits for the percent of days with ≥1 prolonged (>100 seconds) latency were calculated. Acceptable performance was defined as mean latency <30 seconds and ≤0.5% of latencies >100 seconds. Testing conditions included fixed locations of devices in high signal strength locations. Mean latencies were <1 second for iPad and iPod devices (WLAN), and <4 seconds for iPhone (cellular). Among >173,000 iPad and iPod latencies, none were >100 seconds. For iPhone latencies, 0.03% ± 0.01% were >100 seconds. The 95% upper confidence limits of days with ≥1 prolonged latency were 42% (iPhone) and 5% to 8% (iPad, iPod). The APN service was reliable for all studied devices over WLAN and cellular pathways, and performance was better than third party paging systems using Internet connections previously investigated using the same criteria. However, since our study was a best-case assessment, testing is required at individual sites considering use of this technology for critical messaging. Furthermore, since the APN service may fail due to Internet or service provider disruptions, a backup paging system is recommended if the APN service were to be used for critical messaging.

Understanding Similarities and Differences between Parents' and Teachers' Construal of Children's Behaviour

ERIC Educational Resources Information Center

Winterbottom, Mark; Smith, Sarah; Hind, Sally; Haggard, Mark

2008-01-01

Purpose: eduroam[TM] has already been proved to be a scalable, secure and feasible way for universities and research institutions to connect their wireless networks into a WLAN roaming community, but the advantages of eduroam[TM] have not yet been fully discovered in the wireless community networks aimed at regular consumers. This aim of this…

Utilising eduroam[TM] Architecture in Building Wireless Community Networks

ERIC Educational Resources Information Center

Huhtanen, Karri; Vatiainen, Heikki; Keski-Kasari, Sami; Harju, Jarmo

2008-01-01

Purpose: eduroam[TM] has already been proved to be a scalable, secure and feasible way for universities and research institutions to connect their wireless networks into a WLAN roaming community, but the advantages of eduroam[TM] have not yet been fully discovered in the wireless community networks aimed at regular consumers. This aim of this…

Toekomstige Radiocommunicatie in OVO (Soon-to-be Radiocommunication in OVG)

DTIC Science & Technology

2004-12-01

Delft, The Netherlands Brassersplein 2, Delft, The Netherlands 33538 9 . SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES 10. SPONSORING/MONITORING...AGENCY REPORT NUMBER KCenGM Prins Bernhardkazeme, Barchman Wuytierslaan 198, Amersfoort, The Netherlands TD04-0463 11 . SUPPLEMENTARY NO TES Text in...perationeel-technische criteria ............................................................ 9 3. Wireless Local Area Networks (WLANs) en militaire

A synthesis of studies of access point density as a risk factor for road accidents.

PubMed

Elvik, Rune

2017-10-01

Studies of the relationship between access point density (number of access points, or driveways, per kilometre of road) and accident frequency or rate (number of accidents per unit of exposure) have consistently found that accident rate increases when access point density increases. This paper presents a formal synthesis of the findings of these studies. It was found that the addition of one access point per kilometre of road is associated with an increase of 4% in the expected number of accidents, controlling for traffic volume. Although studies consistently indicate an increase in accident rate as access point density increases, the size of the increase varies substantially between studies. In addition to reviewing studies of access point density as a risk factor, the paper discusses some issues related to formally synthesising regression coefficients by applying the inverse-variance method of meta-analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Public Exposure from Indoor Radiofrequency Radiation in the City of Hebron, West Bank-Palestine.

PubMed

Lahham, Adnan; Sharabati, Afefeh; ALMasri, Hussien

2015-08-01

This work presents the results of measured indoor exposure levels to radiofrequency (RF) radiation emitting sources in one of the major cities in the West Bank-the city of Hebron. Investigated RF emitters include FM, TV broadcasting stations, mobile telephony base stations, cordless phones [Digital Enhanced Cordless Telecommunications (DECT)], and wireless local area networks (WLAN). Measurements of power density were conducted in 343 locations representing different site categories in the city. The maximum total power density found at any location was about 2.3 × 10 W m with a corresponding exposure quotient of about 0.01. This value is well below unity, indicating compliance with the guidelines of the International Commission on Non-ionizing Radiation Protection (ICNIRP). The average total exposure from all RF sources was 0.08 × 10 W m. The relative contributions from different sources to the total exposure in terms of exposure quotient were evaluated and found to be 46% from FM radio, 26% from GSM900, 15% from DECT phones, 9% from WLAN, 3% from unknown sources, and 1% from TV broadcasting. RF sources located outdoors contribute about 73% to the population exposure indoors.

Advanced Resistive Exercise Device (ARED) Flight Software (FSW): A Unique Approach to Exercise in Long Duration Habitats

NASA Technical Reports Server (NTRS)

Mangieri, Mark

2005-01-01

ARED flight instrumentation software is associated with an overall custom designed resistive exercise system that will be deployed on the International Space Station (ISS). This innovative software application fuses together many diverse and new technologies into a robust and usable package. The software takes advantage of touchscreen user interface technology by providing a graphical user interface on a Windows based tablet PC, meeting a design constraint of keyboard-less interaction with flight crewmembers. The software interacts with modified commercial data acquisition (DAQ) hardware to acquire multiple channels of sensor measurment from the ARED device. This information is recorded on the tablet PC and made available, via International Space Station (ISS) Wireless LAN (WLAN) and telemetry subsystems, to ground based mission medics and trainers for analysis. The software includes a feature to accept electronically encoded prescriptions of exercises that guide crewmembers through a customized regimen of resistive weight training, based on personal analysis. These electronically encoded prescriptions are provided to the crew via ISS WLAN and telemetry subsystems. All personal data is securely associated with an individual crew member, based on a PIN ID mechanism.

AR.Drone: security threat analysis and exemplary attack to track persons

NASA Astrophysics Data System (ADS)

Samland, Fred; Fruth, Jana; Hildebrandt, Mario; Hoppe, Tobias; Dittmann, Jana

2012-01-01

In this article we illustrate an approach of a security threat analysis of the quadrocopter AR.Drone, a toy for augmented reality (AR) games. The technical properties of the drone can be misused for attacks, which may relate security and/or privacy aspects. Our aim is to sensitize for the possibility of misuses and the motivation for an implementation of improved security mechanisms of the quadrocopter. We focus primarily on obvious security vulnerabilities (e.g. communication over unencrypted WLAN, usage of UDP, live video streaming via unencrypted WLAN to the control device) of this quadrocopter. We could practically verify in three exemplary scenarios that this can be misused by unauthorized persons for several attacks: high-jacking of the drone, eavesdropping of the AR.Drones unprotected video streams, and the tracking of persons. Amongst other aspects, our current research focuses on the realization of the attack of tracking persons and objects with the drone. Besides the realization of attacks, we want to evaluate the potential of this particular drone for a "safe-landing" function, as well as potential security enhancements. Additionally, in future we plan to investigate an automatic tracking of persons or objects without the need of human interactions.

Revisiting Gaussian Process Regression Modeling for Localization in Wireless Sensor Networks

PubMed Central

Richter, Philipp; Toledano-Ayala, Manuel

2015-01-01

Signal strength-based positioning in wireless sensor networks is a key technology for seamless, ubiquitous localization, especially in areas where Global Navigation Satellite System (GNSS) signals propagate poorly. To enable wireless local area network (WLAN) location fingerprinting in larger areas while maintaining accuracy, methods to reduce the effort of radio map creation must be consolidated and automatized. Gaussian process regression has been applied to overcome this issue, also with auspicious results, but the fit of the model was never thoroughly assessed. Instead, most studies trained a readily available model, relying on the zero mean and squared exponential covariance function, without further scrutinization. This paper studies the Gaussian process regression model selection for WLAN fingerprinting in indoor and outdoor environments. We train several models for indoor/outdoor- and combined areas; we evaluate them quantitatively and compare them by means of adequate model measures, hence assessing the fit of these models directly. To illuminate the quality of the model fit, the residuals of the proposed model are investigated, as well. Comparative experiments on the positioning performance verify and conclude the model selection. In this way, we show that the standard model is not the most appropriate, discuss alternatives and present our best candidate. PMID:26370996

Design and Implementation of Low Profile Antenna for Dual-Band Applications Using Rotated E-Shaped Conductor-Backed Plane

PubMed Central

Jalali, Mahdi; Sedghi, Tohid; Shafei, Shahin

2014-01-01

A novel configuration of a printed monopole antenna with a very compact size for satisfying WLAN operations at the 5.2/5.8 GHz and also for X-band operations at the 10 GHz has been proposed. The antenna includes a simple square-shaped patch as the radiator, the rotated U-shaped conductor back plane element with embedded strip on it, and the partial rectangular ground surface. By using the rotated U-shaped conductor-backed plane with proper values, good impedance matching and improvement in bandwidth can be achieved, at the lower and upper bands. The impedance bandwidth for S 11 < −10 dB is about 1.15 GHz for 5 GHz band and 5.3 GHz for X-band. The measured peak gains are about 1.9 dBi at WLAN-band and 4.2 dBi at X-band. The experimental results represent that the realized antenna with good omnidirectional radiation characteristics, enough impedance bandwidth, and reasonable gains can be appropriate for various applications of the future developed technologies and handheld devices. PMID:24711732

Miniaturized printed K shaped monopole antenna with truncated ground plane for 2.4/5.2/5.5/5.8 wireless lan applications

NASA Astrophysics Data System (ADS)

Chandan, Bharti, Gagandeep; Srivastava, Toolika; Rai, B. S.

2018-04-01

A novel truncated ground plane monopole antenna is proposed for wide band wireless local area network (WLAN) applications. The antenna contains a rectangular patch with a rectangular ring, a circular slot and a truncated ground plane printed on opposite sides of a low cost substrate FR4. The operating frequency bands for the antenna are band1 (2.4-2.88 GHz) and band 2 (4.8-6.3 GHz) with ≤ - 10 dB return loss which covers 2.4/5.2/5.5/5.8 GHz WLAN bands. The antenna is compact with overall dimension 26×40×0.8 mmł and with the dimension of patch 16×16×0.8 mm3. The two bands of antenna is obtained by cutting a rectangular ring and a circular slot in the patch and return loss is improved by cutting two rectangular slot in the ground plane. Performance measures of the antenna are shown in terms of return loss, current distribution, radiation pattern and gain. To verify the simulated results, the antenna is also fabricated and tested. The simulated and fabricated results have been found in good agreement.

A Very Compact and Low Profile UWB Planar Antenna with WLAN Band Rejection

PubMed Central

Syed, Avez; Aldhaheri, Rabah W.

2016-01-01

A low-cost coplanar waveguide fed compact ultrawideband (UWB) antenna with band rejection characteristics for wireless local area network (WLAN) is proposed. The notch band characteristic is achieved by etching half wavelength C-shaped annular ring slot in the radiating patch. By properly choosing the radius and position of the slot, the notch band can be adjusted and controlled. With an overall size of 18.7 mm × 17.6 mm, the antenna turns out to be one of the smallest UWB antennas with band-notched characteristics. It has a wide fractional bandwidth of 130% (2.9–13.7 GHz) with VSWR < 2 and rejecting IEEE 802.11a and HIPERLAN/2 frequency band of 5.1–5.9 GHz. Stable omnidirectional radiation patterns in the H plane with an average gain of 4.4 dBi are obtained. The band-notch mechanism of the proposed antenna is examined by HFSS simulator. A good agreement is found between measured and simulated results indicating that the proposed antenna is well suited for integration into portable devices for UWB applications. PMID:27088125

Exposure caused by wireless technologies used for short-range indoor communication in homes and offices.

PubMed

Schmid, G; Lager, D; Preiner, P; Uberbacher, R; Cecil, S

2007-01-01

In order to estimate typical radio frequency exposures from indoor used wireless communication technologies applied in homes and offices, WLAN, Bluetooth and Digital Enhanced Cordless Telecommunications systems, as well as baby surveillance devices and wireless headphones for indoor usage, have been investigated by measurements and numerical computations. Based on optimised measurement methods, field distributions and resulting exposure were assessed on selected products and real exposure scenarios. Additionally, generic scenarios have been investigated on the basis of numerical computations. The obtained results demonstrate that under usual conditions the resulting spatially (over body dimensions) averaged and 6-min time-averaged exposure for persons in the radio frequency fields of the considered applications is below approximately 0.1% of the reference level for power density according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines published in 1998. Spatial and temporal peak values can be considerably higher by 2-3 orders of magnitude. In case of some transmitting devices operated in close proximity to the body (e.g. WLAN transmitters), local exposure can reach the same order of magnitude as the basic restriction; however, none of the devices considered in this study exceeded the limits according to the ICNIRP guidelines.

Open-source telemedicine platform for wireless medical video communication.

PubMed

Panayides, A; Eleftheriou, I; Pantziaris, M

2013-01-01

An m-health system for real-time wireless communication of medical video based on open-source software is presented. The objective is to deliver a low-cost telemedicine platform which will allow for reliable remote diagnosis m-health applications such as emergency incidents, mass population screening, and medical education purposes. The performance of the proposed system is demonstrated using five atherosclerotic plaque ultrasound videos. The videos are encoded at the clinically acquired resolution, in addition to lower, QCIF, and CIF resolutions, at different bitrates, and four different encoding structures. Commercially available wireless local area network (WLAN) and 3.5G high-speed packet access (HSPA) wireless channels are used to validate the developed platform. Objective video quality assessment is based on PSNR ratings, following calibration using the variable frame delay (VFD) algorithm that removes temporal mismatch between original and received videos. Clinical evaluation is based on atherosclerotic plaque ultrasound video assessment protocol. Experimental results show that adequate diagnostic quality wireless medical video communications are realized using the designed telemedicine platform. HSPA cellular networks provide for ultrasound video transmission at the acquired resolution, while VFD algorithm utilization bridges objective and subjective ratings.

Using Vegetation Barriers to Improving Wireless Network Isolation and Security

NASA Astrophysics Data System (ADS)

Cuiñas, Iñigo; Gómez, Paula; Sánchez, Manuel García; Alejos, Ana Vázquez

The increasing number of wireless LANs using the same spectrum allocation could induce multiple interferences and it also could force the active LANs to continuously retransmit data in order to solve this problem: this solution overloads the spectrum bands as well as collapses the LAN transmission capacity. This upcoming problem can be mitigated by using different techniques, being site shielding one of them. If radio systems could be safeguarded against radiation from transmitters out of the specific network, the frequency reuse is improved and, as a consequence, the number of WLANs sharing the same area may increase maintaining the required quality standards. The proposal of this paper is the use of bushes as a hurdle to attenuate signals from other networks and, so that, to defend the own wireless system from outer interferences. A measurement campaign has been performed in order to test this application of vegetal elements. This campaign was focused on determining the attenuation induced by several specimens of seven different vegetal species. Then, the relation between the induced attenuation and the interference from adjacent networks has been computed in terms of separation between networks. The network protection against outer unauthorized access could be also improved by means of the proposed technique.

Trial of real-time locating and messaging system with Bluetooth low energy.

PubMed

Arisaka, Naoya; Mamorita, Noritaka; Isonaka, Risa; Kawakami, Tadashi; Takeuchi, Akihiro

2016-09-14

Hospital real-time location systems (RTLS) are increasing efficiency and reducing operational costs, but room access tags are necessary. We developed three iPhone 5 applications for an RTLS and communications using Bluetooth low energy (BLE). The applications were: Peripheral device tags, Central beacons, and a Monitor. A Peripheral communicated with a Central using BLE. The Central communicated with a Monitor using sockets on TCP/IP (Transmission Control Protocol/Internet Protocol) via a WLAN (wireless local area network). To determine a BLE threshold level for the received signal strength indicator (RSSI), relationships between signal strength and distance were measured in our laboratory and on the terrace. The BLE RSSI threshold was set at -70 dB, about 10 m. While an individual with a Peripheral moved around in a concrete building, the Peripheral was captured in a few 10-sec units at about 10 m from a Central. The Central and Monitor showed and saved the approach events, location, and Peripheral's nickname sequentially in real time. Remote Centrals also interactively communicate with Peripherals by intermediating through Monitors that found the nickname in the event database. Trial applications using BLE on iPhones worked well for patient tracking, and messaging in indoor environments.

Open-Source Telemedicine Platform for Wireless Medical Video Communication

PubMed Central

Panayides, A.; Eleftheriou, I.; Pantziaris, M.

2013-01-01

An m-health system for real-time wireless communication of medical video based on open-source software is presented. The objective is to deliver a low-cost telemedicine platform which will allow for reliable remote diagnosis m-health applications such as emergency incidents, mass population screening, and medical education purposes. The performance of the proposed system is demonstrated using five atherosclerotic plaque ultrasound videos. The videos are encoded at the clinically acquired resolution, in addition to lower, QCIF, and CIF resolutions, at different bitrates, and four different encoding structures. Commercially available wireless local area network (WLAN) and 3.5G high-speed packet access (HSPA) wireless channels are used to validate the developed platform. Objective video quality assessment is based on PSNR ratings, following calibration using the variable frame delay (VFD) algorithm that removes temporal mismatch between original and received videos. Clinical evaluation is based on atherosclerotic plaque ultrasound video assessment protocol. Experimental results show that adequate diagnostic quality wireless medical video communications are realized using the designed telemedicine platform. HSPA cellular networks provide for ultrasound video transmission at the acquired resolution, while VFD algorithm utilization bridges objective and subjective ratings. PMID:23573082

A Middleware Based Approach to Dynamically Deploy Location Based Services onto Heterogeneous Mobile Devices Using Bluetooth in Indoor Environment

NASA Astrophysics Data System (ADS)

Sadhukhan, Pampa; Sen, Rijurekha; Das, Pradip K.

Several methods for providing location based service (LBS) to mobile devices in indoor environment using wireless technologies like WLAN, RFID and Bluetooth have been proposed, implemented and evaluated. However, most of them do not focus on heterogeneity of mobile platforms, memory constraint of mobile devices, the adaptability of client or device to the new services it discovers whenever it reaches a new location. In this paper, we have proposed a Middleware based approach of LBS provision in the indoor environment, where a Bluetooth enabled Base Station (BS) detects Bluetooth enabled mobile devices and pushes a proper client application only to those devices that belong to some registered subscriber of LBS. This dynamic deployment enables the mobile clients to access any new service without having preinstalled interface to that service beforehand and thus the client's memory consumption is reduced. Our proposed work also addresses the other issues like authenticating the clients before providing them LBSs and introducing paid services. We have evaluated its performance in term of file transfer time with respect to file size and throughput with respect to distance. Experimental results on service consumption time by the mobile client for different services are also presented.

Enhanced Handover Decision Algorithm in Heterogeneous Wireless Network

PubMed Central

Abdullah, Radhwan Mohamed; Zukarnain, Zuriati Ahmad

2017-01-01

Transferring a huge amount of data between different network locations over the network links depends on the network’s traffic capacity and data rate. Traditionally, a mobile device may be moved to achieve the operations of vertical handover, considering only one criterion, that is the Received Signal Strength (RSS). The use of a single criterion may cause service interruption, an unbalanced network load and an inefficient vertical handover. In this paper, we propose an enhanced vertical handover decision algorithm based on multiple criteria in the heterogeneous wireless network. The algorithm consists of three technology interfaces: Long-Term Evolution (LTE), Worldwide interoperability for Microwave Access (WiMAX) and Wireless Local Area Network (WLAN). It also employs three types of vertical handover decision algorithms: equal priority, mobile priority and network priority. The simulation results illustrate that the three types of decision algorithms outperform the traditional network decision algorithm in terms of handover number probability and the handover failure probability. In addition, it is noticed that the network priority handover decision algorithm produces better results compared to the equal priority and the mobile priority handover decision algorithm. Finally, the simulation results are validated by the analytical model. PMID:28708067

Collaborative Indoor Access Point Localization Using Autonomous Mobile Robot Swarm.

PubMed

Awad, Fahed; Naserllah, Muhammad; Omar, Ammar; Abu-Hantash, Alaa; Al-Taj, Abrar

2018-01-31

Localization of access points has become an important research problem due to the wide range of applications it addresses such as dismantling critical security threats caused by rogue access points or optimizing wireless coverage of access points within a service area. Existing proposed solutions have mostly relied on theoretical hypotheses or computer simulation to demonstrate the efficiency of their methods. The techniques that rely on estimating the distance using samples of the received signal strength usually assume prior knowledge of the signal propagation characteristics of the indoor environment in hand and tend to take a relatively large number of uniformly distributed random samples. This paper presents an efficient and practical collaborative approach to detect the location of an access point in an indoor environment without any prior knowledge of the environment. The proposed approach comprises a swarm of wirelessly connected mobile robots that collaboratively and autonomously collect a relatively small number of non-uniformly distributed random samples of the access point's received signal strength. These samples are used to efficiently and accurately estimate the location of the access point. The experimental testing verified that the proposed approach can identify the location of the access point in an accurate and efficient manner.

Capacity Estimation Model for Signalized Intersections under the Impact of Access Point

PubMed Central

Zhao, Jing; Li, Peng; Zhou, Xizhao

2016-01-01

Highway Capacity Manual 2010 provides various factors to adjust the base saturation flow rate for the capacity analysis of signalized intersections. No factors, however, is considered for the potential change of signalized intersections capacity caused by the access point closeing to the signalized intersection. This paper presented a theoretical model to estimate the lane group capacity at signalized intersections with the consideration of the effects of access points. Two scenarios of access point locations, upstream or downstream of the signalized intersection, and impacts of six types of access traffic flow are taken into account. The proposed capacity model was validated based on VISSIM simulation. Results of extensive numerical analysis reveal the substantial impact of access point on the capacity, which has an inverse correlation with both the number of major street lanes and the distance between the intersection and access point. Moreover, among the six types of access traffic flows, the access traffic flow 1 (right-turning traffic from major street), flow 4 (left-turning traffic from access point), and flow 5 (left-turning traffic from major street) cause a more significant effect on lane group capacity than others. Some guidance on the mitigation of the negative effect is provided for practitioners. PMID:26726998

Role-based access control permissions

DOEpatents

Staggs, Kevin P.; Markham, Thomas R.; Hull Roskos, Julie J.; Chernoguzov, Alexander

2017-04-25

Devices, systems, and methods for role-based access control permissions are disclosed. One method includes a policy decision point that receives up-to-date security context information from one or more outside sources to determine whether to grant access for a data client to a portion of the system and creates an access vector including the determination; receiving, via a policy agent, a request by the data client for access to the portion of the computing system by the data client, wherein the policy agent checks to ensure there is a session established with communications and user/application enforcement points; receiving, via communications policy enforcement point, the request from the policy agent, wherein the communications policy enforcement point determines whether the data client is an authorized node, based upon the access vector received from the policy decision point; and receiving, via the user/application policy enforcement point, the request from the communications policy enforcement point.

Three dimensional indoor positioning based on visible light with Gaussian mixture sigma-point particle filter technique

NASA Astrophysics Data System (ADS)

Gu, Wenjun; Zhang, Weizhi; Wang, Jin; Amini Kashani, M. R.; Kavehrad, Mohsen

2015-01-01

Over the past decade, location based services (LBS) have found their wide applications in indoor environments, such as large shopping malls, hospitals, warehouses, airports, etc. Current technologies provide wide choices of available solutions, which include Radio-frequency identification (RFID), Ultra wideband (UWB), wireless local area network (WLAN) and Bluetooth. With the rapid development of light-emitting-diodes (LED) technology, visible light communications (VLC) also bring a practical approach to LBS. As visible light has a better immunity against multipath effect than radio waves, higher positioning accuracy is achieved. LEDs are utilized both for illumination and positioning purpose to realize relatively lower infrastructure cost. In this paper, an indoor positioning system using VLC is proposed, with LEDs as transmitters and photo diodes as receivers. The algorithm for estimation is based on received-signalstrength (RSS) information collected from photo diodes and trilateration technique. By appropriately making use of the characteristics of receiver movements and the property of trilateration, estimation on three-dimensional (3-D) coordinates is attained. Filtering technique is applied to enable tracking capability of the algorithm, and a higher accuracy is reached compare to raw estimates. Gaussian mixture Sigma-point particle filter (GM-SPPF) is proposed for this 3-D system, which introduces the notion of Gaussian Mixture Model (GMM). The number of particles in the filter is reduced by approximating the probability distribution with Gaussian components.

The Security Aspects of Wireless Local Area Network (WLAN)

DTIC Science & Technology

2003-09-01

by wireless links to enable devices to communicate. In a Bluetooth network, mobile routers control the changing network topologies of these... Bluetooth Bluetooth is a simple peer-to-peer protocol created to connect multiple consumer mobile information devices (cellular phones, laptops...technology [Ref 2]. Bluetooth enables mobile devices to avoid interference from other signals by hopping to a new frequency after transmitting or

Collaborative Indoor Access Point Localization Using Autonomous Mobile Robot Swarm

PubMed Central

Awad, Fahed; Naserllah, Muhammad; Omar, Ammar; Abu-Hantash, Alaa; Al-Taj, Abrar

2018-01-01

Localization of access points has become an important research problem due to the wide range of applications it addresses such as dismantling critical security threats caused by rogue access points or optimizing wireless coverage of access points within a service area. Existing proposed solutions have mostly relied on theoretical hypotheses or computer simulation to demonstrate the efficiency of their methods. The techniques that rely on estimating the distance using samples of the received signal strength usually assume prior knowledge of the signal propagation characteristics of the indoor environment in hand and tend to take a relatively large number of uniformly distributed random samples. This paper presents an efficient and practical collaborative approach to detect the location of an access point in an indoor environment without any prior knowledge of the environment. The proposed approach comprises a swarm of wirelessly connected mobile robots that collaboratively and autonomously collect a relatively small number of non-uniformly distributed random samples of the access point’s received signal strength. These samples are used to efficiently and accurately estimate the location of the access point. The experimental testing verified that the proposed approach can identify the location of the access point in an accurate and efficient manner. PMID:29385042

CINAHL and MEDLINE: a comparison of indexing practices.

PubMed

Brenner, S H; McKinin, E J

1989-10-01

A random sample of fifty nursing articles indexed in both MEDLINE and CINAHL (NURSING & ALLIED HEALTH) during 1986 was used for comparing indexing practices. Indexing was analyzed by counting the number of major descriptors, the number of major and minor descriptors, the number of indexing access points, the number of common indexing access points, and the number and type of unique indexing access points. The study results indicate: there are few differences in the number of major descriptors used, MEDLINE uses almost twice as many descriptors, MEDLINE has almost twice as many indexing access points, and MEDLINE and CINAHL provide few common access points.

CINAHL and MEDLINE: a comparison of indexing practices.

PubMed Central

Brenner, S H; McKinin, E J

1989-01-01

A random sample of fifty nursing articles indexed in both MEDLINE and CINAHL (NURSING & ALLIED HEALTH) during 1986 was used for comparing indexing practices. Indexing was analyzed by counting the number of major descriptors, the number of major and minor descriptors, the number of indexing access points, the number of common indexing access points, and the number and type of unique indexing access points. The study results indicate: there are few differences in the number of major descriptors used, MEDLINE uses almost twice as many descriptors, MEDLINE has almost twice as many indexing access points, and MEDLINE and CINAHL provide few common access points. PMID:2676049

Development of True Time Delay Circuits

DTIC Science & Technology

2014-06-13

public release Distribution is unlimited DATA SHEET SKY65014-70LF: 0.1-7.0 GHz InGaP Cascadable Amplifier Applications • Wireless infrastructure: WLAN ...decoupling network out of band. For low frequency applications , R1 may be used to conveniently limit supply current on the Evaluation Board. The Evaluation...additional information, refer to the Skyworks Application Note, Solder Reflow Information, document number 200164. Care must be taken when attaching this

A hybrid stochastic approach for self-location of wireless sensors in indoor environments.

PubMed

Lloret, Jaime; Tomas, Jesus; Garcia, Miguel; Canovas, Alejandro

2009-01-01

Indoor location systems, especially those using wireless sensor networks, are used in many application areas. While the need for these systems is widely proven, there is a clear lack of accuracy. Many of the implemented applications have high errors in their location estimation because of the issues arising in the indoor environment. Two different approaches had been proposed using WLAN location systems: on the one hand, the so-called deductive methods take into account the physical properties of signal propagation. These systems require a propagation model, an environment map, and the position of the radio-stations. On the other hand, the so-called inductive methods require a previous training phase where the system learns the received signal strength (RSS) in each location. This phase can be very time consuming. This paper proposes a new stochastic approach which is based on a combination of deductive and inductive methods whereby wireless sensors could determine their positions using WLAN technology inside a floor of a building. Our goal is to reduce the training phase in an indoor environment, but, without an loss of precision. Finally, we compare the measurements taken using our proposed method in a real environment with the measurements taken by other developed systems. Comparisons between the proposed system and other hybrid methods are also provided.

A Hybrid Stochastic Approach for Self-Location of Wireless Sensors in Indoor Environments

PubMed Central

Lloret, Jaime; Tomas, Jesus; Garcia, Miguel; Canovas, Alejandro

2009-01-01

Indoor location systems, especially those using wireless sensor networks, are used in many application areas. While the need for these systems is widely proven, there is a clear lack of accuracy. Many of the implemented applications have high errors in their location estimation because of the issues arising in the indoor environment. Two different approaches had been proposed using WLAN location systems: on the one hand, the so-called deductive methods take into account the physical properties of signal propagation. These systems require a propagation model, an environment map, and the position of the radio-stations. On the other hand, the so-called inductive methods require a previous training phase where the system learns the received signal strength (RSS) in each location. This phase can be very time consuming. This paper proposes a new stochastic approach which is based on a combination of deductive and inductive methods whereby wireless sensors could determine their positions using WLAN technology inside a floor of a building. Our goal is to reduce the training phase in an indoor environment, but, without an loss of precision. Finally, we compare the measurements taken using our proposed method in a real environment with the measurements taken by other developed systems. Comparisons between the proposed system and other hybrid methods are also provided. PMID:22412334

Feasibility of Smartphone Based Photogrammetric Point Clouds for the Generation of Accessibility Maps

NASA Astrophysics Data System (ADS)

Angelats, E.; Parés, M. E.; Kumar, P.

2018-05-01

Accessible cities with accessible services are an old claim of people with reduced mobility. But this demand is still far away of becoming a reality as lot of work is required to be done yet. First step towards accessible cities is to know about real situation of the cities and its pavement infrastructure. Detailed maps or databases on street slopes, access to sidewalks, mobility in public parks and gardens, etc. are required. In this paper, we propose to use smartphone based photogrammetric point clouds, as a starting point to create accessible maps or databases. This paper analyses the performance of these point clouds and the complexity of the image acquisition procedure required to obtain them. The paper proves, through two test cases, that smartphone technology is an economical and feasible solution to get the required information, which is quite often seek by city planners to generate accessible maps. The proposed approach paves the way to generate, in a near term, accessibility maps through the use of point clouds derived from crowdsourced smartphone imagery.

A medical application integrating remote 3D visualization tools to access picture archiving and communication system on mobile devices.

PubMed

He, Longjun; Ming, Xing; Liu, Qian

2014-04-01

With computing capability and display size growing, the mobile device has been used as a tool to help clinicians view patient information and medical images anywhere and anytime. However, for direct interactive 3D visualization, which plays an important role in radiological diagnosis, the mobile device cannot provide a satisfactory quality of experience for radiologists. This paper developed a medical system that can get medical images from the picture archiving and communication system on the mobile device over the wireless network. In the proposed application, the mobile device got patient information and medical images through a proxy server connecting to the PACS server. Meanwhile, the proxy server integrated a range of 3D visualization techniques, including maximum intensity projection, multi-planar reconstruction and direct volume rendering, to providing shape, brightness, depth and location information generated from the original sectional images for radiologists. Furthermore, an algorithm that changes remote render parameters automatically to adapt to the network status was employed to improve the quality of experience. Finally, performance issues regarding the remote 3D visualization of the medical images over the wireless network of the proposed application were also discussed. The results demonstrated that this proposed medical application could provide a smooth interactive experience in the WLAN and 3G networks.

Wireless Local Area Network (WLAN) Vulnerability Assessment and Security

DTIC Science & Technology

2005-09-01

even that they have a Bluetooth device to begin with. Bluetooth attacks can permit network sniffing, device detection, data and services theft . Two...the Bluetooth v1.1 Foundation Specifications9. One major security issue is the fact that the Bluetooth standard allows a single device to communicate...simultaneously with multiple other devices . Many Bluetooth radios are embedded in devices and users often do not realize whether they are on or

On Ramps: Options and Issues in Accessing the Internet.

ERIC Educational Resources Information Center

Bocher, Bob

1995-01-01

Outlines the basic options that schools and libraries have for accessing the Internet, focusing on four models: direct connection; dial access using SLIP/PPP (Serial Line Internet Protocol/Point-to-Point Protocol); dial-up using terminal emulation mode; and dial access through commercial online services. Discusses access option issues such as…

An Indoor Pedestrian Positioning Method Using HMM with a Fuzzy Pattern Recognition Algorithm in a WLAN Fingerprint System

PubMed Central

Ni, Yepeng; Liu, Jianbo; Liu, Shan; Bai, Yaxin

2016-01-01

With the rapid development of smartphones and wireless networks, indoor location-based services have become more and more prevalent. Due to the sophisticated propagation of radio signals, the Received Signal Strength Indicator (RSSI) shows a significant variation during pedestrian walking, which introduces critical errors in deterministic indoor positioning. To solve this problem, we present a novel method to improve the indoor pedestrian positioning accuracy by embedding a fuzzy pattern recognition algorithm into a Hidden Markov Model. The fuzzy pattern recognition algorithm follows the rule that the RSSI fading has a positive correlation to the distance between the measuring point and the AP location even during a dynamic positioning measurement. Through this algorithm, we use the RSSI variation trend to replace the specific RSSI value to achieve a fuzzy positioning. The transition probability of the Hidden Markov Model is trained by the fuzzy pattern recognition algorithm with pedestrian trajectories. Using the Viterbi algorithm with the trained model, we can obtain a set of hidden location states. In our experiments, we demonstrate that, compared with the deterministic pattern matching algorithm, our method can greatly improve the positioning accuracy and shows robust environmental adaptability. PMID:27618053

7 CFR 1739.3 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... terrestrial technology having the capacity to provide transmission facilities that enable subscribers of the...) Computer Access Points and wireless access, that is used for the purposes of providing free access to and..., and after normal working hours and on Saturdays or Sunday. Computer Access Point means a new computer...

46 CFR 188.10-56 - Pilot boarding equipment and point of access.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Pilot boarding equipment and point of access. 188.10-56... VESSELS GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 188.10-56 Pilot boarding equipment and point of access. (a) Pilot boarding equipment means a pilot ladder, accomodation ladder, pilot...

Information Transfer Ion Wireless Networks

DTIC Science & Technology

2010-07-01

conferences with proceed- ings to be made available online in the IEEE Xplore database, namely IFIP Wireless Days (WD 2008) at Dubai, UAE, and the...Poland, May 2008, pp. 61-64, IEEE Xplore , DOI = 10.1109/INFTECH. 2008.4621591. 2. J. Konorski, IEEE 802.11 LAN Capacity: Incentives and Incentive...2008, Dubai, UAE, Nov. 2008, IEEE Xplore DOI = 10.1109/WD.2008.4812857. 4. J. Konorski, QoS Provision in an Ad Hoc IEEE 802.11 WLAN: A Bayesian War

Information Transfer in Wireless Networks

DTIC Science & Technology

2010-07-01

conferences with proceed- ings to be made available online in the IEEE Xplore database, namely IFIP Wireless Days (WD 2008) at Dubai, UAE, and the...Poland, May 2008, pp. 61-64, IEEE Xplore , DOI = 10.1109/INFTECH. 2008.4621591. 2. J. Konorski, IEEE 802.11 LAN Capacity: Incentives and Incentive...2008, Dubai, UAE, Nov. 2008, IEEE Xplore DOI = 10.1109/WD.2008.4812857. 4. J. Konorski, QoS Provision in an Ad Hoc IEEE 802.11 WLAN: A Bayesian War

Adaptive threshold determination for efficient channel sensing in cognitive radio network using mobile sensors

NASA Astrophysics Data System (ADS)

Morshed, M. N.; Khatun, S.; Kamarudin, L. M.; Aljunid, S. A.; Ahmad, R. B.; Zakaria, A.; Fakir, M. M.

2017-03-01

Spectrum saturation problem is a major issue in wireless communication systems all over the world. Huge number of users is joining each day to the existing fixed band frequency but the bandwidth is not increasing. These requirements demand for efficient and intelligent use of spectrum. To solve this issue, the Cognitive Radio (CR) is the best choice. Spectrum sensing of a wireless heterogeneous network is a fundamental issue to detect the presence of primary users' signals in CR networks. In order to protect primary users (PUs) from harmful interference, the spectrum sensing scheme is required to perform well even in low signal-to-noise ratio (SNR) environments. Meanwhile, the sensing period is usually required to be short enough so that secondary (unlicensed) users (SUs) can fully utilize the available spectrum. CR networks can be designed to manage the radio spectrum more efficiently by utilizing the spectrum holes in primary user's licensed frequency bands. In this paper, we have proposed an adaptive threshold detection method to detect presence of PU signal using free space path loss (FSPL) model in 2.4 GHz WLAN network. The model is designed for mobile sensors embedded in smartphones. The mobile sensors acts as SU while the existing WLAN network (channels) works as PU. The theoretical results show that the desired threshold range detection of mobile sensors mainly depends on the noise floor level of the location in consideration.

An efficient hexagonal switched beam antenna structure based on Fabry-Perot cavity leaky-wave antenna

NASA Astrophysics Data System (ADS)

Aymen El Cafsi, Mohamed; Nedil, Mourad; Osman, Lotfi; Gharsallah, Ali

2015-11-01

A novel design of switched beam antenna (SBA) system based on Fabry-Perot cavity leaky-wave antenna (FPC LWA) is designed and fabricated for base station operating in the unlicensed ISM central frequency band at 5.8 GHz of the wireless local area network (WLAN) standard. The proposed SBA is designed with hexagonal shape of FPC LWA Arrays in order to get 360° of coverage. The single element of FPC LWA array is composed of a patch antenna and covered by a Partially Reflective Surface (PRS), which is composed of a Metal Strip Grating and printed on a high permittivity Superstrate. First, the Transmission Line Model of FPC LWA is introduced to analyse and calculate the far-field components in E- and H planes by using the Transverse Equivalent Network. This approach is then compared with other full wave's commercial software such as Ansoft HFSS and CST Microwave Studio. Second, a parametric study is performed to evaluate the effect of the angle formed by the two successive FPC LWA on the radiation efficiency of the activate sector. To examine the performance of the proposed SBA, experimental prototype was fabricated and measured. As a result, multiple orthogonal beams (six beams) of 10 dBi of gain with low Side Lobes Level and 360° of coverage are produced. This SBA structure is suitable for WLAN communication systems.

Development of an RF-EMF Exposure Surrogate for Epidemiologic Research.

PubMed

Roser, Katharina; Schoeni, Anna; Bürgi, Alfred; Röösli, Martin

2015-05-22

Exposure assessment is a crucial part in studying potential effects of RF-EMF. Using data from the HERMES study on adolescents, we developed an integrative exposure surrogate combining near-field and far-field RF-EMF exposure in a single brain and whole-body exposure measure. Contributions from far-field sources were modelled by propagation modelling and multivariable regression modelling using personal measurements. Contributions from near-field sources were assessed from both, questionnaires and mobile phone operator records. Mean cumulative brain and whole-body doses were 1559.7 mJ/kg and 339.9 mJ/kg per day, respectively. 98.4% of the brain dose originated from near-field sources, mainly from GSM mobile phone calls (93.1%) and from DECT phone calls (4.8%). Main contributors to the whole-body dose were GSM mobile phone calls (69.0%), use of computer, laptop and tablet connected to WLAN (12.2%) and data traffic on the mobile phone via WLAN (6.5%). The exposure from mobile phone base stations contributed 1.8% to the whole-body dose, while uplink exposure from other people's mobile phones contributed 3.6%. In conclusion, the proposed approach is considered useful to combine near-field and far-field exposure to an integrative exposure surrogate for exposure assessment in epidemiologic studies. However, substantial uncertainties remain about exposure contributions from various near-field and far-field sources.

Development of an RF-EMF Exposure Surrogate for Epidemiologic Research

PubMed Central

Roser, Katharina; Schoeni, Anna; Bürgi, Alfred; Röösli, Martin

2015-01-01

Exposure assessment is a crucial part in studying potential effects of RF-EMF. Using data from the HERMES study on adolescents, we developed an integrative exposure surrogate combining near-field and far-field RF-EMF exposure in a single brain and whole-body exposure measure. Contributions from far-field sources were modelled by propagation modelling and multivariable regression modelling using personal measurements. Contributions from near-field sources were assessed from both, questionnaires and mobile phone operator records. Mean cumulative brain and whole-body doses were 1559.7 mJ/kg and 339.9 mJ/kg per day, respectively. 98.4% of the brain dose originated from near-field sources, mainly from GSM mobile phone calls (93.1%) and from DECT phone calls (4.8%). Main contributors to the whole-body dose were GSM mobile phone calls (69.0%), use of computer, laptop and tablet connected to WLAN (12.2%) and data traffic on the mobile phone via WLAN (6.5%). The exposure from mobile phone base stations contributed 1.8% to the whole-body dose, while uplink exposure from other people’s mobile phones contributed 3.6%. In conclusion, the proposed approach is considered useful to combine near-field and far-field exposure to an integrative exposure surrogate for exposure assessment in epidemiologic studies. However, substantial uncertainties remain about exposure contributions from various near-field and far-field sources. PMID:26006132

A New Ticket-Based Authentication Mechanism for Fast Handover in Mesh Network.

PubMed

Lai, Yan-Ming; Cheng, Pu-Jen; Lee, Cheng-Chi; Ku, Chia-Yi

2016-01-01

Due to the ever-growing popularity mobile devices of various kinds have received worldwide, the demands on large-scale wireless network infrastructure development and enhancement have been rapidly swelling in recent years. A mobile device holder can get online at a wireless network access point, which covers a limited area. When the client leaves the access point, there will be a temporary disconnection until he/she enters the coverage of another access point. Even when the coverages of two neighboring access points overlap, there is still work to do to make the wireless connection smoothly continue. The action of one wireless network access point passing a client to another access point is referred to as the handover. During handover, for security concerns, the client and the new access point should perform mutual authentication before any Internet access service is practically gained/provided. If the handover protocol is inefficient, in some cases discontinued Internet service will happen. In 2013, Li et al. proposed a fast handover authentication mechanism for wireless mesh network (WMN) based on tickets. Unfortunately, Li et al.'s work came with some weaknesses. For one thing, some sensitive information such as the time and date of expiration is sent in plaintext, which increases security risks. For another, Li et al.'s protocol includes the use of high-quality tamper-proof devices (TPDs), and this unreasonably high equipment requirement limits its applicability. In this paper, we shall propose a new efficient handover authentication mechanism. The new mechanism offers a higher level of security on a more scalable ground with the client's privacy better preserved. The results of our performance analysis suggest that our new mechanism is superior to some similar mechanisms in terms of authentication delay.

A New Ticket-Based Authentication Mechanism for Fast Handover in Mesh Network

PubMed Central

Lai, Yan-Ming; Cheng, Pu-Jen; Lee, Cheng-Chi; Ku, Chia-Yi

2016-01-01

Due to the ever-growing popularity mobile devices of various kinds have received worldwide, the demands on large-scale wireless network infrastructure development and enhancement have been rapidly swelling in recent years. A mobile device holder can get online at a wireless network access point, which covers a limited area. When the client leaves the access point, there will be a temporary disconnection until he/she enters the coverage of another access point. Even when the coverages of two neighboring access points overlap, there is still work to do to make the wireless connection smoothly continue. The action of one wireless network access point passing a client to another access point is referred to as the handover. During handover, for security concerns, the client and the new access point should perform mutual authentication before any Internet access service is practically gained/provided. If the handover protocol is inefficient, in some cases discontinued Internet service will happen. In 2013, Li et al. proposed a fast handover authentication mechanism for wireless mesh network (WMN) based on tickets. Unfortunately, Li et al.’s work came with some weaknesses. For one thing, some sensitive information such as the time and date of expiration is sent in plaintext, which increases security risks. For another, Li et al.’s protocol includes the use of high-quality tamper-proof devices (TPDs), and this unreasonably high equipment requirement limits its applicability. In this paper, we shall propose a new efficient handover authentication mechanism. The new mechanism offers a higher level of security on a more scalable ground with the client’s privacy better preserved. The results of our performance analysis suggest that our new mechanism is superior to some similar mechanisms in terms of authentication delay. PMID:27171160

A Clock Fingerprints-Based Approach for Wireless Transmitter Identification

NASA Astrophysics Data System (ADS)

Zhao, Caidan; Xie, Liang; Huang, Lianfen; Yao, Yan

Cognitive radio (CR) was proposed as one of the promising solutions for low spectrum utilization. However, security problems such as the primary user emulation (PUE) attack severely limit its applications. In this paper, we propose a clock fingerprints-based authentication approach to prevent PUE attacks in CR networks with the help of curve fitting and classifier. An experimental setup was constructed using the WLAN cards and software radio devices, and the corresponding results show that satisfied identification can be achieved for wireless transmitters.

elevatr: Access Elevation Data from Various APIs

EPA Science Inventory

Several web services are available that provide access to elevation data. This package provides access to several of those services and returns elevation data either as a SpatialPointsDataFrame from point elevation services or as a raster object from raster elevation services. ...

Saving energy for the data collection point in WBAN network

NASA Astrophysics Data System (ADS)

Nguyen-Duc, Toan; Kamioka, Eiji

2017-11-01

Wireless sensor networking (WSN) has been rapidly developed and become essential in various domains including health care systems. Such systems use WSN to collect real-time medical sensed data, aiming at improving the patient safety. For instance, patients suffered from adverse events, i.e., cardiac or respiratory arrests, are monitored so as to prevent them from getting harm. Sensors are placed on, in or near the patients' body to continuously collect sensing data such as the electrocardiograms, blood oxygenation, breathing, and heart rate. In this case, the sensors form a subcategory of WSN called wireless body area network (WBAN). In WBAN, sensing data are sent to one or more data collection points called personal server (PS). The role of PS is important since it forwards sensed data, to a medical server via a Bluetooth/WLAN connection in real time to support storage of information and real-time diagnosis, the device can also issue a notification of an emergency status. Since PS is a battery-based device, when its battery is empty, it will disconnect the sensed medical data with the rest network. To best of our knowledge, very few studies that focus on saving energy for the PS. To this end, this work investigates the trade-off between energy consumption for wireless communication and the amount of sensing data. An energy consumption model for wireless communication has been proposed based on direct measurement using real testbed. According to our findings, it is possible to save energy for the PS by selecting suitable wireless technology to be used based on the amount of data to be transmitted.

Behavioral study and design of a digital interpolator filter for wireless reconfigurable transmitters

NASA Astrophysics Data System (ADS)

Ferragina, V.; Frassone, A.; Ghittori, N.; Malcovati, P.; Vigna, A.

2005-06-01

The behavioral analysis and the design in a 0.13 μm CMOS technology of a digital interpolator filter for wireless applications are presented. The proposed block is designed to be embedded in the baseband part of a reconfigurable transmitter (WLAN 802.11a, UMTS) to operate as a sampling frequency boost between the digital signal processor (DSP) and the digital-to-analog converter (DAC). In recent trends the DAC of such transmitters usually operates at high conversion frequencies (to allow a relaxed implementation of the following analog reconstruction filter), while the DSP output flows at low frequencies (typically Nyquist rate). Thus a block able to increase the digital data rate, like the one proposed, is needed before the DAC. For example, in the WLAN case, an interpolation factor of 4 has been used, allowing the digital data frequency to raise from 20 MHz to 80 MHz. Using a time-domain model of the TX chain, a behavioral analysis has been performed to determine the impact of the filter performance on the quality of the signal at the antenna. This study has led to the evaluation of the z-domain filter transfer function, together with the specifications concerning a finite precision implementation. A VHDL description has allowed an automatic synthesis of the circuit in a 0.13 μm CMOS technology (with a supply voltage of 1.2 V). Post-synthesis simulations have confirmed the effectiveness of the proposed study.

Browsing for the Best Internet Access Provider?

ERIC Educational Resources Information Center

Weil, Marty

1996-01-01

Highlights points to consider when choosing an Internet Service Provider. Serial Line Internet Protocol (SLIP) and Point to Point Protocol (PPP) are compared regarding price, performance, bandwidth, speed, and technical support. Obtaining access via local, national, consumer online, and telephone-company providers is discussed. A pricing chart and…

Deficits in Young Men's Knowledge about Accessing Sexual and Reproductive Health Services

ERIC Educational Resources Information Center

Bersamin, Melina; Fisher, Deborah A.; Marcell, Arik V.; Finan, Laura J.

2017-01-01

Objective: The current study aimed to examine (1) gender differences in college students' knowledge of sexual and reproductive health care (K-SRHC) service access points, and (2) the relationship between demographic and psychosocial factors and college students' overall K-SRHC service access points. Methods and Participants: Self-report online…

Accurate 3D Positioning for a Mobile Platform in Non-Line-of-Sight Scenarios Based on IMU/Magnetometer Sensor Fusion.

PubMed

Hellmers, Hendrik; Kasmi, Zakaria; Norrdine, Abdelmoumen; Eichhorn, Andreas

2018-01-04

In recent years, a variety of real-time applications benefit from services provided by localization systems due to the advent of sensing and communication technologies. Since the Global Navigation Satellite System (GNSS) enables localization only outside buildings, applications for indoor positioning and navigation use alternative technologies. Ultra Wide Band Signals (UWB), Wireless Local Area Network (WLAN), ultrasonic or infrared are common examples. However, these technologies suffer from fading and multipath effects caused by objects and materials in the building. In contrast, magnetic fields are able to pass through obstacles without significant propagation errors, i.e. in Non-Line of Sight Scenarios (NLoS). The aim of this work is to propose a novel indoor positioning system based on artificially generated magnetic fields in combination with Inertial Measurement Units (IMUs). In order to reach a better coverage, multiple coils are used as reference points. A basic algorithm for three-dimensional applications is demonstrated as well as evaluated in this article. The established system is then realized by a sensor fusion principle as well as a kinematic motion model on the basis of a Kalman filter. Furthermore, a pressure sensor is used in combination with an adaptive filtering method to reliably estimate the platform's altitude.

Creating a mobile subject guide to improve access to point-of-care resources for medical students: a case study

PubMed Central

Boruff, Jill T; Bilodeau, Edward

2012-01-01

Question: Can a mobile optimized subject guide facilitate medical student access to mobile point-of-care tools? Setting: The guide was created at a library at a research-intensive university with six teaching hospital sites. Objectives: The team created a guide facilitating medical student access to point-of-care tools directly on mobile devices to provide information allowing them to access and set up resources with little assistance. Methods: Two librarians designed a mobile optimized subject guide for medicine and conducted a survey to test its usefulness. Results: Web analytics and survey results demonstrate that the guide is used and the students are satisfied. Conclusion: The library will continue to use the subject guide as its primary means of supporting mobile devices. It remains to be seen if the mobile guide facilitates access for those who do not need assistance and want direct access to the resources. Internet access in the hospitals remains an issue. PMID:22272160

Creating a mobile subject guide to improve access to point-of-care resources for medical students: a case study.

PubMed

Boruff, Jill T; Bilodeau, Edward

2012-01-01

Can a mobile optimized subject guide facilitate medical student access to mobile point-of-care tools? The guide was created at a library at a research-intensive university with six teaching hospital sites. The team created a guide facilitating medical student access to point-of-care tools directly on mobile devices to provide information allowing them to access and set up resources with little assistance. Two librarians designed a mobile optimized subject guide for medicine and conducted a survey to test its usefulness. Web analytics and survey results demonstrate that the guide is used and the students are satisfied. The library will continue to use the subject guide as its primary means of supporting mobile devices. It remains to be seen if the mobile guide facilitates access for those who do not need assistance and want direct access to the resources. Internet access in the hospitals remains an issue.

Securing Wireless Local Area Networks with GoC PKI

DTIC Science & Technology

2007-10-01

de réseau privé virtuel (RPV) sans fil sur un banc d’essai dans le laboratoire des Opérations d’information de réseau (OIR) pour des ...locaux sans fil (WLAN) dans les réseaux d’entreprise du gouvernement. Dans ce rapport, on présente les résultats de travaux complémentaires qui tirent...mutuelle, l’autorisation, la protection et l’intégrité des données, ainsi que la gestion et la diffusion des politiques sur les

Human movement activity classification approaches that use wearable sensors and mobile devices

NASA Astrophysics Data System (ADS)

Kaghyan, Sahak; Sarukhanyan, Hakob; Akopian, David

2013-03-01

Cell phones and other mobile devices become part of human culture and change activity and lifestyle patterns. Mobile phone technology continuously evolves and incorporates more and more sensors for enabling advanced applications. Latest generations of smart phones incorporate GPS and WLAN location finding modules, vision cameras, microphones, accelerometers, temperature sensors etc. The availability of these sensors in mass-market communication devices creates exciting new opportunities for data mining applications. Particularly healthcare applications exploiting build-in sensors are very promising. This paper reviews different approaches of human activity recognition.

Coexistence of Collocated IEEE 802.11 and Bluetooth Technologies in 2.4 GHz ISM Band

NASA Astrophysics Data System (ADS)

Xhafa, Ariton E.; Lu, Xiaolin; Shaver, Donald P.

In this paper, we investigate coexistence of collocated 802.11 and Bluetooth technologies in 2.4 GHz industrial, scientific, and medical (ISM) band. To that end, we show a time division multiplexing approach suffers from the “avalanche effect”. We then provide remedies to avoid this effect and improve the performance of the overall network. For example, it is shown that a simple request-to-send (RTS) / clear-to-send (CTS) frame handshake in WLAN can avoid “avalanche effect” and improve the performance of overall network.

Information infrastructure for emergency medical services.

PubMed

Orthner, Helmuth; Mishra, Ninad; Terndrup, Thomas; Acker, Joseph; Grimes, Gary; Gemmill, Jill; Battles, Marcie

2005-01-01

The pre-hospital emergency medical and public safety information environment is nearing a threshold of significant change. The change is driven in part by several emerging technologies such as secure, high-speed wireless communication in the local and wide area networks (wLAN, 3G), Geographic Information Systems (GIS), Global Positioning Systems (GPS), and powerful handheld computing and communication services, that are of sufficient utility to be more widely adopted. We propose a conceptual model to enable improved clinical decision making in the pre-hospital environment using these change agents.

76 FR 36154 - In the Matter of Certain Equipment for Communications Networks, Including Switches, Routers...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-21

... Communications Networks, Including Switches, Routers, Gateways, Bridges, Wireless Access Points, Cable Modems, IP... networks, including switches, routers, gateways, bridges, wireless access points, cable modems, IP phones... points, cable modems, IP phones, and products containing same that infringe one or more of claims 1, 5, 9...

77 FR 6601 - Facility Operating License Amendment From Nine Mile Point Nuclear Station, LLC.; Nine Mile Point...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-08

... (or its counsel or representative) to digitally sign documents and access the E-Submittal server for... Information (SGI) is necessary to respond to this notice must request document access by February 21, 2012... instructions on submitting comments and instructions on accessing documents related to this action, see [[Page...

Contextual view of Point Bonita Ridge, showing Bonita Ridge access ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Contextual view of Point Bonita Ridge, showing Bonita Ridge access road retaining wall and location of Signal Corps Radar (S.C.R.) 296 Station 5 Transmitter Building foundation (see stake at center left), camera facing north - Fort Barry, Signal Corps Radar 296, Station 5, Transmitter Building Foundation, Point Bonita, Marin Headlands, Sausalito, Marin County, CA

76 FR 30196 - Notice of Receipt of Complaint; Solicitation of Comments Relating to the Public Interest

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-24

... Access Points, Cable Modems, IP Phones, and Products Containing Same, DN 2807; the Commission is..., wireless, access points, cable modems, IP phones, and products containing same. The complaint names as...

elevatr: Access Elevation Data from Various APIs | Science ...

EPA Pesticide Factsheets

Several web services are available that provide access to elevation data. This package provides access to several of those services and returns elevation data either as a SpatialPointsDataFrame from point elevation services or as a raster object from raster elevation services. Currently, the package supports access to the Mapzen Elevation Service, Mapzen Terrain Service, and the USGS Elevation Point Query Service. The R language for statistical computing is increasingly used for spatial data analysis . This R package, elevatr, is in response to this and provides access to elevation data from various sources directly in R. The impact of `elevatr` is that it will 1) facilitate spatial analysis in R by providing access to foundational dataset for many types of analyses (e.g. hydrology, limnology) 2) open up a new set of users and uses for APIs widely used outside of R, and 3) provide an excellent example federal open source development as promoted by the Federal Source Code Policy (https://sourcecode.cio.gov/).

Experiences of registered nurses with regard to accessing health information at the point-of-care via mobile computing devices.

PubMed

Ricks, Esmeralda; Benjamin, Valencia; Williams, Margaret

2015-11-19

The volume of health information necessary to provide competent health care today has become overwhelming. Mobile computing devices are fast becoming an essential clinical tool for accessing health information at the point-of-care of patients. This study explored and described how registered nurses experienced accessing information at the point-of-care via mobile computing devices (MCDs). A qualitative, exploratory, descriptive and contextual design was used. Ten in-depth interviews were conducted with purposively sampled registered nurses employed by a state hospital in the Nelson Mandela Bay Municipality (NMBM). Interviews were recorded, transcribed verbatim and analysed using Tesch's data analysis technique. Ethical principles were adhered to throughout the study. Guba's model of trustworthiness was used to confirm integrity of the study. Four themes emerged which revealed that the registered nurses benefited from the training they received by enabling them to develop, and improve, their computer literacy levels. Emphasis was placed on the benefits that the accessed information had for educational purposes for patients and the public, for colleagues and students. Furthermore the ability to access information at the point-of-care was considered by registered nurses as valuable to improve patient care because of the wide range of accurate and readily accessible information available via the mobile computing device. The registered nurses in this study felt that being able to access information at the point-of-care increased their confidence and facilitated the provision of quality care because it assisted them in being accurate and sure of what they were doing.

Pin routability and pin access analysis on standard cells for layout optimization

NASA Astrophysics Data System (ADS)

Chen, Jian; Wang, Jun; Zhu, ChengYu; Xu, Wei; Li, Shuai; Lin, Eason; Ou, Odie; Lai, Ya-Chieh; Qu, Shengrui

2018-03-01

At advanced process nodes, especially at sub-28nm technology, pin accessibility and routability of standard cells has become one of the most challenging design issues due to the limited router tracks and the increased pin density. If this issue can't be found and resolved during the cell design stage, the pin access problem will be very difficult to be fixed in implementation stage and will make the low efficiency for routing. In this paper, we will introduce a holistic approach for the pin accessibility scoring and routability analysis. For accessibility, the systematic calculator which assigns score for each pin will search the available access points, consider the surrounded router layers, basic design rule and allowed via geometry. Based on the score, the "bad" pins can be found and modified. On pin routability analysis, critical pin points (placing via on this point would lead to failed via insertion) will be searched out for either layout optimization guide or set as OBS for via insertion blocking. By using this pin routability and pin access analysis flow, we are able to improve the library quality and performance.

A preliminary report on the genetic variation in pointed gourd (Trichosanthes dioica Roxb.) as assessed by random amplified polymorphic DNA.

PubMed

Adhikari, S; Biswas, A; Bandyopadhyay, T K; Ghosh, P D

2014-06-01

Pointed gourd (Trichosanthes dioica Roxb.) is an economically important cucurbit and is extensively propagated through vegetative means, viz vine and root cuttings. As the accessions are poorly characterized it is important at the beginning of a breeding programme to discriminate among available genotypes to establish the level of genetic diversity. The genetic diversity of 10 pointed gourd races, referred to as accessions was evaluated. DNA profiling was generated using 10 sequence independent RAPD markers. A total of 58 scorable loci were observed out of which 18 (31.03%) loci were considered polymorphic. Genetic diversity parameters [average and effective number of alleles, Shannon's index, percent polymorphism, Nei's gene diversity, polymorphic information content (PIC)] for RAPD along with UPGMA clustering based on Jaccard's coefficient were estimated. The UPGMA dendogram constructed based on RAPD analysis in 10 pointed gourd accessions were found to be grouped in a single cluster and may represent members of one heterotic group. RAPD analysis showed promise as an effective tool in estimating genetic polymorphism in different accessions of pointed gourd.

77 FR 21996 - Certain Equipment for Communications Networks, Including Switches, Routers, Gateways, Bridges...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-12

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-778] Certain Equipment for Communications Networks, Including Switches, Routers, Gateways, Bridges, Wireless Access Points, Cable Modems, IP Phones... networks, including switches, routers, gateways, bridges, wireless access points, cable modems, IP phones...

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

DOEpatents

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

DOEpatents

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.

A system for ubiquitous health monitoring in the bedroom via a Bluetooth network and wireless LAN.

PubMed

Choi, J M; Choi, B H; Seo, J W; Sohn, R H; Ryu, M S; Yi, W; Park, K S

2004-01-01

Advances in information technology have enabled ubiquitous health monitoring at home, which is particularly useful for patients, who have to live alone. We have focused on the automatic and unobtrusive measurement of biomedical signals and activities of patients. We have constructed wireless communication networks in order to transfer data. The networks consist of Bluetooth and Wireless Local Area Network (WLAN). In this paper, we present the concept of a ubiquitous-Bedroom (u-Bedroom) which is a part of a ubiquitous-House (u-House) and we present our systems for ubiquitous health monitoring.

Compact electromagnetic bandgap structures for notch band in ultra-wideband applications.

PubMed

Rotaru, Mihai; Sykulski, Jan

2010-01-01

This paper introduces a novel approach to create notch band filters in the front-end of ultra-wideband (UWB) communication systems based on electromagnetic bandgap (EBG) structures. The concept presented here can be implemented in any structure that has a microstrip in its configuration. The EBG structure is first analyzed using a full wave electromagnetic solver and then optimized to work at WLAN band (5.15-5.825 GHz). Two UWB passband filters are used to demonstrate the applicability and effectiveness of the novel EBG notch band feature. Simulation results are provided for two cases studied.

Left-handed compact MIMO antenna array based on wire spiral resonator for 5-GHz wireless applications

NASA Astrophysics Data System (ADS)

Alqadami, Abdulrahman Shueai Mohsen; Jamlos, Mohd Faizal; Soh, Ping Jack; Rahim, Sharul Kamal Abdul; Narbudowicz, Adam

2017-01-01

A compact coplanar waveguide-fed multiple-input multiple-output antenna array based on the left-handed wire loaded spiral resonators (SR) is presented. The proposed antenna consists of a 2 × 2 wire SR with two symmetrical microstrip feed lines, each line exciting a 1 × 2 wire SR. Left-handed metamaterial unit cells are placed on its reverse side and arranged in a 2 × 3 array. A reflection coefficient of less than -16 dB and mutual coupling of less than -28 dB are achieved at 5.15 GHz WLAN band.

Compact Electromagnetic Bandgap Structures for Notch Band in Ultra-Wideband Applications

PubMed Central

Rotaru, Mihai; Sykulski, Jan

2010-01-01

This paper introduces a novel approach to create notch band filters in the front-end of ultra-wideband (UWB) communication systems based on electromagnetic bandgap (EBG) structures. The concept presented here can be implemented in any structure that has a microstrip in its configuration. The EBG structure is first analyzed using a full wave electromagnetic solver and then optimized to work at WLAN band (5.15–5.825 GHz). Two UWB passband filters are used to demonstrate the applicability and effectiveness of the novel EBG notch band feature. Simulation results are provided for two cases studied. PMID:22163430

Miniaturized Pi (Π) - Slit monopole antenna for 2.4/5.2/5.8 applications

NASA Astrophysics Data System (ADS)

Chandan, Bharti, Gagandeep; Bharti, Pradutt Kumar; Rai, B. S.

2018-04-01

In present paper, two - shaped slots are inserted in a rectangular patch of a monopole antenna for dual band operation. The antenna design is very simple, compact and light weight with overall dimension 29×38×0.8 mm3. Prototype of the proposed antenna is constructed and tested to verify its usefulness for 2.4/5.2/5.8 ghz wlan/wimax applications. It has been observed that both simulated and measured results have good agreement and measured peak gain and radiation pattern are suitable as per the need of application.

Development of Curie point switching for thin film, random access, memory device

NASA Technical Reports Server (NTRS)

Lewicki, G. W.; Tchernev, D. I.

1967-01-01

Managanese bismuthide films are used in the development of a random access memory device of high packing density and nondestructive readout capability. Memory entry is by Curie point switching using a laser beam. Readout is accomplished by microoptical or micromagnetic scanning.

Accessing care summaries at point-of-care:Implementation of mobile devices for personal carers in aged care.

PubMed

Brimelow, Rachel E; Gibney, Annie; Meakin, Suzanne; Wollin, Judy A

2017-04-01

Continued development of mobile technology now allows access to information at the point-of-care. This study was conducted to evaluate the use of one such tool on a mobile device, from the carer perspective. Caregivers across 12 aged-care facilities were supplied mobile devices to access a Picture Care Plan (PCP), a specific tool designed around the role of the personal carer. An anonymous questionnaire was subsequently completed by 85 carers with questions relating to participants' experience. Perceived helpfulness of the PCP at the point-of-care was high (87%). A significant number of participants believed the use of the PCP increased resident safety and quality of care (76%). Practical components related to the carrying of the device, network speed and the requirement to maintain communication with senior members of staff to ascertain updates were also expressed by participants. Findings suggest that staff are receptive to adoption of mobile devices to access care directives at the point-of-care and that the technology is useful.

Performance of FORTRAN floating-point operations on the Flex/32 multicomputer

NASA Technical Reports Server (NTRS)

Crockett, Thomas W.

1987-01-01

A series of experiments has been run to examine the floating-point performance of FORTRAN programs on the Flex/32 (Trademark) computer. The experiments are described, and the timing results are presented. The time required to execute a floating-point operation is found to vary considerbaly depending on a number of factors. One factor of particular interest from an algorithm design standpoint is the difference in speed between common memory accesses and local memory accesses. Common memory accesses were found to be slower, and guidelines are given for determinig when it may be cost effective to copy data from common to local memory.

Evaluation of innovative devices to control traffic entering from low-volume access points within a land closure.

DOT National Transportation Integrated Search

2014-04-01

This report describes the methodology and results of analyses performed to identify and evaluate : alternative methods to control traffic entering a lane closure on a two-lane, two-way road from low-volume : access points. Researchers documented the ...

Achievable Rate Estimation of IEEE 802.11ad Visual Big-Data Uplink Access in Cloud-Enabled Surveillance Applications.

PubMed

Kim, Joongheon; Kim, Jong-Kook

2016-01-01

This paper addresses the computation procedures for estimating the impact of interference in 60 GHz IEEE 802.11ad uplink access in order to construct visual big-data database from randomly deployed surveillance camera sensing devices. The acquired large-scale massive visual information from surveillance camera devices will be used for organizing big-data database, i.e., this estimation is essential for constructing centralized cloud-enabled surveillance database. This performance estimation study captures interference impacts on the target cloud access points from multiple interference components generated by the 60 GHz wireless transmissions from nearby surveillance camera devices to their associated cloud access points. With this uplink interference scenario, the interference impacts on the main wireless transmission from a target surveillance camera device to its associated target cloud access point with a number of settings are measured and estimated under the consideration of 60 GHz radiation characteristics and antenna radiation pattern models.

Metasurface Reflector (MSR) Loading for High Performance Small Microstrip Antenna Design

PubMed Central

Ahsan, Md Rezwanul; Islam, Mohammad Tariqul; Ullah, Mohammad Habib; Singh, Mandeep Jit; Ali, Mohd Tarmizi

2015-01-01

A meander stripline feed multiband microstrip antenna loaded with metasurface reflector (MSR) structure has been designed, analyzed and constructed that offers the wireless communication services for UHF/microwave RFID and WLAN/WiMAX applications. The proposed MSR assimilated antenna comprises planar straight forward design of circular shaped radiator with horizontal slots on it and 2D metasurface formed by the periodic square metallic element that resembles the behavior of metamaterials. A custom made high dielectric bio-plastic substrate (ε r = 15) is used for fabricating the prototype of the MSR embedded planar monopole antenna. The details of the design progress through numerical simulations and experimental results are presented and discussed accordingly. The measured impedance bandwidth, radiation patterns and gain of the proposed MSR integrated antenna are compared with the obtained results from numerical simulation, and a good compliance can be observed between them. The investigation shows that utilization of MSR structure has significantly broadened the -10dB impedance bandwidth than the conventional patch antenna: from 540 to 632 MHz (17%), 467 to 606 MHz (29%) and 758 MHz to 1062 MHz (40%) for three distinct operating bands centered at 0.9, 3.5 and 5.5 GHz. Additionally, due to the assimilation of MSR, the overall realized gains have been upgraded to a higher value of 3.62 dBi, 6.09 dBi and 8.6 dBi for lower, middle and upper frequency band respectively. The measured radiation patterns, impedance bandwidths (S11<-10 dB) and gains from the MSR loaded antenna prototype exhibit reasonable characteristics that can satisfy the requirements of UHF/microwave (5.8 GHz) RFID, WiMAX (3.5/5.5 GHz) and WLAN (5.2/5.8 GHz) applications. PMID:26018795

Metasurface Reflector (MSR) Loading for High Performance Small Microstrip Antenna Design.

PubMed

Ahsan, Md Rezwanul; Islam, Mohammad Tariqul; Ullah, Mohammad Habib; Singh, Mandeep Jit; Ali, Mohd Tarmizi

2015-01-01

A meander stripline feed multiband microstrip antenna loaded with metasurface reflector (MSR) structure has been designed, analyzed and constructed that offers the wireless communication services for UHF/microwave RFID and WLAN/WiMAX applications. The proposed MSR assimilated antenna comprises planar straight forward design of circular shaped radiator with horizontal slots on it and 2D metasurface formed by the periodic square metallic element that resembles the behavior of metamaterials. A custom made high dielectric bio-plastic substrate (εr = 15) is used for fabricating the prototype of the MSR embedded planar monopole antenna. The details of the design progress through numerical simulations and experimental results are presented and discussed accordingly. The measured impedance bandwidth, radiation patterns and gain of the proposed MSR integrated antenna are compared with the obtained results from numerical simulation, and a good compliance can be observed between them. The investigation shows that utilization of MSR structure has significantly broadened the -10 dB impedance bandwidth than the conventional patch antenna: from 540 to 632 MHz (17%), 467 to 606 MHz (29%) and 758 MHz to 1062 MHz (40%) for three distinct operating bands centered at 0.9, 3.5 and 5.5 GHz. Additionally, due to the assimilation of MSR, the overall realized gains have been upgraded to a higher value of 3.62 dBi, 6.09 dBi and 8.6 dBi for lower, middle and upper frequency band respectively. The measured radiation patterns, impedance bandwidths (S11<-10 dB) and gains from the MSR loaded antenna prototype exhibit reasonable characteristics that can satisfy the requirements of UHF/microwave (5.8 GHz) RFID, WiMAX (3.5/5.5 GHz) and WLAN (5.2/5.8 GHz) applications.

An antenna-pointing mechanism for the ETS-6 K-band Single Access (KSA) antenna

NASA Technical Reports Server (NTRS)

Takada, Noboru; Amano, Takahiro; Ohhashi, Toshiro; Wachi, Shigeo

1991-01-01

Both the design philosophy for the Antenna Pointing Mechanism (APM) to be used for the K-band Single Access (KSA) antenna system and experimental results of the APM Engineering Model (EM) tests are described. The KSA antenna system will be flown on the Engineering Test Satellite 6 (ETS-6).

46 CFR 188.10-56 - Pilot boarding equipment and point of access.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Pilot boarding equipment and point of access. 188.10-56 Section 188.10-56 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 188.10-56 Pilot boarding...

46 CFR 188.10-56 - Pilot boarding equipment and point of access.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Pilot boarding equipment and point of access. 188.10-56 Section 188.10-56 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 188.10-56 Pilot boarding...

46 CFR 188.10-56 - Pilot boarding equipment and point of access.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Pilot boarding equipment and point of access. 188.10-56 Section 188.10-56 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 188.10-56 Pilot boarding...

46 CFR 188.10-56 - Pilot boarding equipment and point of access.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Pilot boarding equipment and point of access. 188.10-56 Section 188.10-56 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 188.10-56 Pilot boarding...

Public Internet Access Points (PIAPs) and Their Social Impact: A Case Study from Turkey

ERIC Educational Resources Information Center

Afacan, Gulgun; Er, Erkan; Arifoglu, Ali

2013-01-01

Building public Internet access points (PIAPs) is a significant contribution of governments towards achieving an information society. While many developing countries are investing great amounts to establish PIAPs today, people may not use PIAPs effectively. Yet, the successful implementation of PIAPs is the result of citizens' acceptance to use…

An Experimental Performance Measurement of Implemented Wireless Access Point for Interworking Wi-Fi and HSDPA Networks

NASA Astrophysics Data System (ADS)

Byun, Tae-Young

This paper presents a prototype of WAP(Wireless Access Point) that provides the wireless Internet access anywhere. Implemented WAP can be equipped with various wireless WAN interfaces such as WCDMA and HSDPA. WAP in the IP mechanism has to process connection setup procedure to one wireless WAN. Also, WAP can provide connection management procedures to reconnect interrupted connection automatically. By using WAP, several mobile devices such as netbook, UMPC and smart-phone in a moving vehicle can access to HSDPA network simultaneously. So, it has more convenient for using the WAP when there are needs to access wireless Internet more than two mobile devices in restricted spaces such as car, train and ship.

Evaluating the Impact of the Healthy Beverage Executive Order for City Agencies in Boston, Massachusetts, 2011-2013.

PubMed

Cradock, Angie L; Kenney, Erica L; McHugh, Anne; Conley, Lisa; Mozaffarian, Rebecca S; Reiner, Jennifer F; Gortmaker, Steven L

2015-09-10

Intake of sugar-sweetened beverages (SSBs) is associated with negative health effects. Access to healthy beverages may be promoted by policies such as the Healthy Beverage Executive Order (HBEO) established by former Boston mayor Thomas M. Menino, which directed city departments to eliminate the sale of SSBs on city property. Implementation consisted of "traffic-light signage" and educational materials at point of purchase. This study evaluates the impact of the HBEO on changes in beverage availability. Researchers collected data on price, brand, and size of beverages for sale in spring 2011 (899 beverage slots) and for sale in spring 2013, two years after HBEO implementation (836 beverage slots) at access points (n = 31) at city agency locations in Boston. Nutrient data, including calories and sugar content, from manufacturer websites were used to determine HBEO beverage traffic-light classification category. We used paired t tests to examine change in average calories and sugar content of beverages and the proportion of beverages by traffic-light classification at access points before and after HBEO implementation. Average beverage sugar grams and calories at access points decreased (sugar, -13.1 g; calories, -48.6 kcal; p<.001) following the implementation of the HBEO. The average proportion of high-sugar ("red") beverages available per access point declined (-27.8%, p<.001). Beverage prices did not change over time. City agencies were significantly more likely to sell only low-sugar beverages after the HBEO was implemented (OR = 4.88; 95% CI, 1.49-16.0). Policies such as the HBEO can promote community-wide changes that make healthier beverage options more accessible on city-owned properties.

Evaluating the Impact of the Healthy Beverage Executive Order for City Agencies in Boston, Massachusetts, 2011–2013

PubMed Central

Kenney, Erica L.; McHugh, Anne; Conley, Lisa; Mozaffarian, Rebecca S.; Reiner, Jennifer F.; Gortmaker, Steven L.

2015-01-01

Introduction Intake of sugar-sweetened beverages (SSBs) is associated with negative health effects. Access to healthy beverages may be promoted by policies such as the Healthy Beverage Executive Order (HBEO) established by former Boston mayor Thomas M. Menino, which directed city departments to eliminate the sale of SSBs on city property. Implementation consisted of “traffic-light signage” and educational materials at point of purchase. This study evaluates the impact of the HBEO on changes in beverage availability. Methods Researchers collected data on price, brand, and size of beverages for sale in spring 2011 (899 beverage slots) and for sale in spring 2013, two years after HBEO implementation (836 beverage slots) at access points (n = 31) at city agency locations in Boston. Nutrient data, including calories and sugar content, from manufacturer websites were used to determine HBEO beverage traffic-light classification category. We used paired t tests to examine change in average calories and sugar content of beverages and the proportion of beverages by traffic-light classification at access points before and after HBEO implementation. Results Average beverage sugar grams and calories at access points decreased (sugar, −13.1 g; calories, −48.6 kcal; p<.001) following the implementation of the HBEO. The average proportion of high-sugar (“red”) beverages available per access point declined (−27.8%, p<.001). Beverage prices did not change over time. City agencies were significantly more likely to sell only low-sugar beverages after the HBEO was implemented (OR = 4.88; 95% CI, 1.49–16.0). Discussion Policies such as the HBEO can promote community-wide changes that make healthier beverage options more accessible on city-owned properties. PMID:26355828

Trends in Disparities in Low-Income Children's Health Insurance Coverage and Access to Care by Family Immigration Status.

PubMed

Jarlenski, Marian; Baller, Julia; Borrero, Sonya; Bennett, Wendy L

2016-03-01

To examine time trends in disparities in low-income children's health insurance coverage and access to care by family immigration status. We used data from the National Survey of Children's Health in 2003 to 2011-2012, including 83,612 children aged 0 to 17 years with family incomes <200% of the federal poverty level. We examined 3 immigration status categories: citizen children with nonimmigrant parents; citizen children with immigrant parents; and immigrant children. We used multivariable regression analyses to obtain adjusted trends in health insurance coverage and access to care. All low-income children experienced gains in health insurance coverage and access to care from 2003 to 2011-2012, regardless of family immigration status. Relative to citizen children with nonimmigrant parents, citizen children with immigrant parents had a 5 percentage point greater increase in health insurance coverage (P = .06), a 9 percentage point greater increase in having a personal doctor or nurse (P < .01), and an 11 percentage point greater increase in having no unmet medical need (P < .01). Immigrant children had significantly lower health insurance coverage than other groups. However, the group had a 14 percentage point greater increase in having a personal doctor or nurse (P < .01) and a 26 percentage point greater increase in having no unmet medical need (P < .01) relative to citizen children with nonimmigrant parents. Some disparities in access to care related to family immigration status have lessened over time among children in low-income families, although large disparities still exist. Policy efforts are needed to ensure that children of immigrant parents and immigrant children are able to access health insurance and health care. Copyright © 2016 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

Investigation of RF Emissions From Wireless Networks as a Threat to Avionic Systems

NASA Technical Reports Server (NTRS)

Salud, Maria Theresa P.; Williams, Reuben A. (Technical Monitor)

2002-01-01

The paper focuses on understanding and obtaining preliminary measurements of radiated field (RF) emissions of laptop/wireless local area network (WLAN) systems. This work is part of a larger research project to measure radiated emissions of wireless devices to provide a better understanding for potential interference with crucial aircraft avionics systems. A reverberation chamber data collection process is included, as well as recommendations for additional tests. Analysis of measurements from devices under test (DUTs) proved inconclusive for addressing potential interference issues. Continued effort is expected to result in a complete easily reproducible test protocol. The data and protocol presented here are considered preliminary.

A compact planar multi-broad band monopole antenna for mobile devices

NASA Astrophysics Data System (ADS)

Zhong, Xiaoqing; Yao, Bin; Zheng, Qinhong; Yang, Jikong; Cao, Xiangqi

2015-10-01

A Multiple-frequency broadband planar monopole antenna is proposed in this Paper. The antenna is stimulated and numerically optimized by HFSS13.0 (High Frequency Structure Simulator). The size of it is 39mm×22mm×1.7mm. The antenna resonates at many frequencies. The parameter S11<=-6dB means the proposed antenna matches well with its feed-line and covers many useful operation frequency bands, including 2G(DCS1800 and PCS1900), 3G(UMTS), 4G(LTE2300 and LTE2500), ISM, WLAN. It is quiet appropriate for the present ultra-thin smart phones

Tactical Wireless Networking in Coalition Environments: Implementing an IEEE 802.20 Wireless End-User Network Utilizing FLASH-OFDM to Provide a Secure Mobile Extension to Existing WAN

DTIC Science & Technology

2005-09-01

consumption comparisons between 802.11 and 802.20 were conducted. The HP4700’s used a rechargeable 1800 mAh Lithium -ion internal battery and the expansion...jacket with 1840 mAh Lithium -ion internal rechargeable battery . The HP4700 has integrated WLAN 802.11b, Bluetooth®, Fast Infrared, IrDA, USB & Serial...weighs 1150 pounds and includes the weight of a 2 hour backup battery . [Ref 18] The power requirements for the RR are as follows: • +24VDC, -48VDC, 110

Multi-band phase shifter design using modified slotline configuration

NASA Astrophysics Data System (ADS)

Kulandhaisamy, Indhumathi; Rajendran, Dinesh Babu; Kanagasabai, Malathi; Gurusamy, Gunasekaran; Moorthy, Balaji; George, Jithila V.; Lawrance, Livya

2017-01-01

In this paper, an analog multiband phase shifter using slotline configuration is proposed. To implement the design, a pair of modified Split Ring Resonator (SRR) is employed. The periodic property of SRR provides multiband characteristics, whether the coupling slot gives the phase variations over the bands. The operation is well explained with an equivalent circuit model and its characteristics have been studied both in simulation and measurement. The prototype operates in 1.77-2.16, 3.5-3.97, 5.08-5.33, 6.43-6.93, and 8.01-8.59 GHz frequency bands which can be utilized for GSM, GPS, WLAN, C-band, and X-band applications, respectively.

An integrated set of UNIX based system tools at control room level

NASA Astrophysics Data System (ADS)

Potepan, F.; Scafuri, C.; Bortolotto, C.; Surace, G.

1994-12-01

The design effort of providing a simple point-and-click approach to the equipment access has led to the definition and realization of a modular set of software tools to be used at the ELETTRA control room level. Point-to-point equipment access requires neither programming nor specific knowledge of the control system architecture. The development and integration of communication, graphic, editing and global database modules are described in depth, followed by a report of their use in the first commissioning period.

47 CFR 64.5110 - Safeguards on the disclosure of customer proprietary network information.

Code of Federal Regulations, 2013 CFR

2013-10-01

... disclosing CPNI based on a customer-initiated telephone contact, TRS call, point-to-point call, online...) of this section. (c) Online access to CPNI. A TRS provider shall authenticate a customer without the... customer online access to CPNI related to his or her TRS account. Once authenticated, the customer may only...

47 CFR 64.5110 - Safeguards on the disclosure of customer proprietary network information.

Code of Federal Regulations, 2014 CFR

2014-10-01

... disclosing CPNI based on a customer-initiated telephone contact, TRS call, point-to-point call, online...) of this section. (c) Online access to CPNI. A TRS provider shall authenticate a customer without the... customer online access to CPNI related to his or her TRS account. Once authenticated, the customer may only...

Wireless Technology in K-12 Education

ERIC Educational Resources Information Center

Walery, Darrell

2004-01-01

Many schools begin implementing wireless technology slowly by creating wireless "hotspots" on the fly. This is accomplished by putting a wireless access point on a cart along with a set of wireless laptop computers. A teacher can then wheel the cart anywhere in the school that has a network drop, plug the access point in and have an…

Pulse oximeter based mobile biotelemetry application.

PubMed

Işik, Ali Hakan; Güler, Inan

2012-01-01

Quality and features of tele-homecare are improved by information and communication technologies. In this context, a pulse oximeter-based mobile biotelemetry application is developed. With this application, patients can measure own oxygen saturation and heart rate through Bluetooth pulse oximeter at home. Bluetooth virtual serial port protocol is used to send the test results from pulse oximeter to the smart phone. These data are converted into XML type and transmitted to remote web server database via smart phone. In transmission of data, GPRS, WLAN or 3G can be used. The rule based algorithm is used in the decision making process. By default, the threshold value of oxygen saturation is 80; the heart rate threshold values are 40 and 150 respectively. If the patient's heart rate is out of the threshold values or the oxygen saturation is below the threshold value, an emergency SMS is sent to the doctor. By this way, the directing of an ambulance to the patient can be performed by doctor. The doctor for different patients can change these threshold values. The conversion of the result of the evaluated data to SMS XML template is done on the web server. Another important component of the application is web-based monitoring of pulse oximeter data. The web page provides access to of all patient data, so the doctors can follow their patients and send e-mail related to the evaluation of the disease. In addition, patients can follow own data on this page. Eight patients have become part of the procedure. It is believed that developed application will facilitate pulse oximeter-based measurement from anywhere and at anytime.

Multi-tool accessibility assessment of government department websites:a case-study with JKGAD.

PubMed

Ismail, Abid; Kuppusamy, K S; Nengroo, Ab Shakoor

2017-08-02

Nature of being accessible to all categories of users is one of the primary factors for enabling the wider reach of the resources published through World Wide Web. The accessibility of websites has been analyzed through W3C guidelines with the help of various tools. This paper presents a multi-tool accessibility assessment of government department websites belonging to the Indian state of Jammu and Kashmir. A comparative analysis of six accessibility tools is also presented with 14 different parameters. The accessibility analysis tools used in this study for analysis are aChecker, Cynthia Says, Tenon, wave, Mauve, and Hera. These tools provide us the results of selected websites accessibility status on Web Content Accessibility Guidelines (WCAG) 1.0 and 2.0. It was found that there are variations in accessibility analysis results when using different accessibility metrics to measure the accessibility of websites. In addition to this, we have identified the guidelines which have frequently been violated. It was observed that there is a need for incorporating the accessibility component features among the selected websites. This paper presents a set of suggestions to improve the accessibility status of these sites so that the information and services provided by these sites shall reach a wider spectrum of audience without any barrier. Implications for rehabilitation The following points indicates that this case study of JKGAD websites comes under Rehabilitation focused on Visually Impaired users. Due to the universal nature of web, it should be accessible to all according to WCAG guidelines framed by World Wide Web Consortium. In this paper we have identified multiple accessibility barriers for persons with visual impairment while browsing the Jammu and Kashmir Government websites. Multi-tool analysis has been done to pin-point the potential barriers for persons with visually Impaired. Usability analysis has been performed to check whether these websites are suitable for persons with visual impairment. We provide some valuable suggestions which can be followed by developers and designers to minimize these potential accessibility barriers.Based on aforementioned key points, this article helps the persons with disability especially Visually Impaired Users to access the web resources better with the implementation of identified suggestions.

State Medicaid Coverage, ESRD Incidence, and Access to Care

PubMed Central

Goldstein, Benjamin A.; Hall, Yoshio N.; Mitani, Aya A.; Winkelmayer, Wolfgang C.

2014-01-01

The proportion of low-income nonelderly adults covered by Medicaid varies widely by state. We sought to determine whether broader state Medicaid coverage, defined as the proportion of each state’s low-income nonelderly adult population covered by Medicaid, associates with lower state-level incidence of ESRD and greater access to care. The main outcomes were incidence of ESRD and five indicators of access to care. We identified 408,535 adults aged 20–64 years, who developed ESRD between January 1, 2001, and December 31, 2008. Medicaid coverage among low-income nonelderly adults ranged from 12.2% to 66.0% (median 32.5%). For each additional 10% of the low-income nonelderly population covered by Medicaid, there was a 1.8% (95% confidence interval, 1.0% to 2.6%) decrease in ESRD incidence. Among nonelderly adults with ESRD, gaps in access to care between those with private insurance and those with Medicaid were narrower in states with broader coverage. For a 50-year-old white woman, the access gap to the kidney transplant waiting list between Medicaid and private insurance decreased by 7.7 percentage points in high (>45%) versus low (<25%) Medicaid coverage states. Similarly, the access gap to transplantation decreased by 4.0 percentage points and the access gap to peritoneal dialysis decreased by 3.8 percentage points in high Medicaid coverage states. In conclusion, states with broader Medicaid coverage had a lower incidence of ESRD and smaller insurance-related access gaps. PMID:24652791

The effect of access to contraceptive services on injectable use and demand for family planning in Malawi.

PubMed

Skiles, Martha Priedeman; Cunningham, Marc; Inglis, Andrew; Wilkes, Becky; Hatch, Ben; Bock, Ariella; Barden-O'Fallon, Janine

2015-03-01

Previous studies have identified positive relationships between geographic proximity to family planning services and contraceptive use, but have not accounted for the effect of contraceptive supply reliability or the diminishing influence of facility access with increasing distance. Kernel density estimation was used to geographically link Malawi women's use of injectable contraceptives and demand for birth spacing or limiting, as drawn from the 2010 Demographic and Health Survey, with contraceptive logistics data from family planning service delivery points. Linear probability models were run to identify associations between access to injectable services-measured by distance alone and by distance combined with supply reliability-and injectable use and family planning demand among rural and urban populations. Access to services was an important predictor of injectable use. The probability of injectable use among rural women with the most access by both measures was 7‒8 percentage points higher than among rural dwellers with the least access. The probability of wanting to space or limit births among urban women who had access to the most reliable supplies was 18 percentage points higher than among their counterparts with the least access. Product availability in the local service environment plays a critical role in women's demand for and use of contraceptive methods. Use of kernel density estimation in creating facility service environments provides a refined approach to linking women with services and accounts for both distance to facilities and supply reliability. Urban and rural differences should be considered when seeking to improve contraceptive access.

Evaluating Expected Costs and Benefits of Granting Access to New Treatments on the Basis of Progression-Free Survival in Non-Small-Cell Lung Cancer.

PubMed

Lakdawalla, Darius N; Chou, Jacquelyn W; Linthicum, Mark T; MacEwan, Joanna P; Zhang, Jie; Goldman, Dana P

2015-05-01

Surrogate end points may be used as proxy for more robust clinical end points. One prominent example is the use of progression-free survival (PFS) as a surrogate for overall survival (OS) in trials for oncologic treatments. Decisions based on surrogate end points may expedite regulatory approval but may not accurately reflect drug efficacy. Payers and clinicians must balance the potential benefits of earlier treatment access based on surrogate end points against the risks of clinical uncertainty. To present a framework for evaluating the expected net benefit or cost of providing early access to new treatments on the basis of evidence of PFS benefits before OS results are available, using non-small-cell lung cancer (NSCLC) as an example. A probabilistic decision model was used to estimate expected incremental social value of the decision to grant access to a new treatment on the basis of PFS evidence. The model analyzed a hypothetical population of patients with NSCLC who could be treated during the period between PFS and OS evidence publication. Estimates for delay in publication of OS evidence following publication of PFS evidence, expected OS benefit given PFS benefit, incremental cost of new treatment, and other parameters were drawn from the literature on treatment of NSCLC. Incremental social value of early access for each additional patient per month (in 2014 US dollars). For "medium-value" model parameters, early reimbursement of drugs with any PFS benefit yields an incremental social cost of more than $170,000 per newly treated patient per month. In contrast, granting early access on the basis of PFS benefit between 1 and 3.5 months produces more than $73,000 in incremental social value. Across the full range of model parameter values, granting access for drugs with PFS benefit between 3 and 3.5 months is robustly beneficial, generating incremental social value ranging from $38,000 to more than $1 million per newly treated patient per month, whereas access for all drugs with any PFS benefit is usually not beneficial. The value of providing access to new treatments on the basis of surrogate end points, and PFS in particular, likely varies considerably. Payers and clinicians should carefully consider how to use PFS data in balancing potential benefits against costs in each particular disease.

Point Clouds to Indoor/outdoor Accessibility Diagnosis

NASA Astrophysics Data System (ADS)

Balado, J.; Díaz-Vilariño, L.; Arias, P.; Garrido, I.

2017-09-01

This work presents an approach to automatically detect structural floor elements such as steps or ramps in the immediate environment of buildings, elements that may affect the accessibility to buildings. The methodology is based on Mobile Laser Scanner (MLS) point cloud and trajectory information. First, the street is segmented in stretches along the trajectory of the MLS to work in regular spaces. Next, the lower region of each stretch (the ground zone) is selected as the ROI and normal, curvature and tilt are calculated for each point. With this information, points in the ROI are classified in horizontal, inclined or vertical. Points are refined and grouped in structural elements using raster process and connected components in different phases for each type of previously classified points. At last, the trajectory data is used to distinguish between road and sidewalks. Adjacency information is used to classify structural elements in steps, ramps, curbs and curb-ramps. The methodology is tested in a real case study, consisting of 100 m of an urban street. Ground elements are correctly classified in an acceptable computation time. Steps and ramps also are exported to GIS software to enrich building models from Open Street Map with information about accessible/inaccessible entrances and their locations.

Subject Access Points in the MARC Record and Archival Finding Aid: Enough or Too Many?

ERIC Educational Resources Information Center

Cox, Elizabeth; Czechowski, Leslie

2007-01-01

In this research project, the authors set out to discover the current practice in both the archival and cataloging worlds for usage of access points in descriptive records and to learn how archival descriptive practices fit into long-established library cataloging procedures and practices. A sample of archival finding aids and MARC records at 123…

33 CFR 165.809 - Security Zones; Port of Port Lavaca-Point Comfort, Point Comfort, TX and Port of Corpus Christi...

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION AREAS AND LIMITED ACCESS AREAS Specific Regulated Navigation Areas and Limited Access Areas Eighth Coast Guard District § 165.809 Security Zones; Port of Port...) Location. The following area is designated as a security zone: all waters of the Corpus Christi Inner...

Assessing river recreation use and perceptions of environmental quality trends on Michigan's upper Manistee River

Treesearch

Charles Nelson; Brian Valentine

2003-01-01

Through vehicle counts and windshield surveys at 43 public access points and a mail questionnaire to shoreline property owners, Michigan State University researchers estimated the recreation effort on a 55-mile stretch of Michigan's upper Manistee River from April 28 - September 3, 2001. In addition, public access point user satisfaction, perceived trends in the...

A MAP fixed-point, packing-unpacking routine for the IBM 7094 computer

Treesearch

Robert S. Helfman

1966-01-01

Two MAP (Macro Assembly Program) computer routines for packing and unpacking fixed point data are described. Use of these routines with Fortran IV Programs provides speedy access to quantities of data which far exceed the normal storage capacity of IBM 7000-series computers. Many problems that could not be attempted because of the slow access-speed of tape...

Advanced mobility handover for mobile IPv6 based wireless networks.

PubMed

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

2014-01-01

We propose an Advanced Mobility Handover scheme (AMH) in this paper for seamless mobility in MIPv6-based wireless networks. In the proposed scheme, the mobile node utilizes a unique home IPv6 address developed to maintain communication with other corresponding nodes without a care-of-address during the roaming process. The IPv6 address for each MN during the first round of AMH process is uniquely identified by HA using the developed MN-ID field as a global permanent, which is identifying uniquely the IPv6 address of MN. Moreover, a temporary MN-ID is generated by access point each time an MN is associated with a particular AP and temporarily saved in a developed table inside the AP. When employing the AMH scheme, the handover process in the network layer is performed prior to its default time. That is, the mobility handover process in the network layer is tackled by a trigger developed AMH message to the next access point. Thus, a mobile node keeps communicating with the current access point while the network layer handover is executed by the next access point. The mathematical analyses and simulation results show that the proposed scheme performs better as compared with the existing approaches.

Passive serialization in a multitasking environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hennessey, J.P.; Osisek, D.L.; Seigh, J.W. II

1989-02-28

In a multiprocessing system having a control program in which data objects are shared among processes, this patent describes a method for serializing references to a data object by the processes so as to prevent invalid references to the data object by any process when an operation requiring exclusive access is performed by another process, comprising the steps of: permitting the processes to reference data objects on a shared access basis without obtaining a shared lock; monitoring a point of execution of the control program which is common to all processes in the system, which occurs regularly in the process'more » execution and across which no references to any data object can be maintained by any process, except references using locks; establishing a system reference point which occurs after each process in the system has passed the point of execution at least once since the last such system reference point; requesting an operation requiring exclusive access on a selected data object; preventing subsequent references by other processes to the selected data object; waiting until two of the system references points have occurred; and then performing the requested operation.« less

Assured Access/Mobile Computing Initiatives on Five University Campuses.

ERIC Educational Resources Information Center

Blurton, Craig; Chee, Yam San; Long, Phillip D.; Resmer, Mark; Runde, Craig

Mobile computing and assured access are becoming popular terms to describe a growing number of university programs which take advantage of ubiquitous network access points and the portability of notebook computers to ensure all students have access to digital tools and resources. However, the implementation of such programs varies widely from…

Tracking Human Mobility Using WiFi Signals.

PubMed

Sapiezynski, Piotr; Stopczynski, Arkadiusz; Gatej, Radu; Lehmann, Sune

2015-01-01

We study six months of human mobility data, including WiFi and GPS traces recorded with high temporal resolution, and find that time series of WiFi scans contain a strong latent location signal. In fact, due to inherent stability and low entropy of human mobility, it is possible to assign location to WiFi access points based on a very small number of GPS samples and then use these access points as location beacons. Using just one GPS observation per day per person allows us to estimate the location of, and subsequently use, WiFi access points to account for 80% of mobility across a population. These results reveal a great opportunity for using ubiquitous WiFi routers for high-resolution outdoor positioning, but also significant privacy implications of such side-channel location tracking.

Analysis of Airport Access - A Methods Review and Research Program

DOT National Transportation Integrated Search

1971-10-01

The report points up the differences and similarities between airport access travel and general urban trip making. Models and surveys developed for, or applicable, to airport access planning are reviewed. A research proram is proposed which would gen...

Rethinking Mobile Telephony with the IMP

DTIC Science & Technology

2011-01-01

in the telephony industry, and portions of it such as SS7 or SCTP signaling are packet-switched, deployed mobile telephony access infrastructure is...deployment of wireless LAN technology raises the question of how a mobile telephony system might instead be architected to use wireless LAN access ...and wireless access points has made universal Internet access increasingly convenient. There are clearly barriers to this vision of accessing a

Design and implementation of flexible TWDM-PON with PtP WDM overlay based on WSS for next-generation optical access networks

NASA Astrophysics Data System (ADS)

Wu, Bin; Yin, Hongxi; Qin, Jie; Liu, Chang; Liu, Anliang; Shao, Qi; Xu, Xiaoguang

2016-09-01

Aiming at the increasing demand of the diversification services and flexible bandwidth allocation of the future access networks, a flexible passive optical network (PON) scheme combining time and wavelength division multiplexing (TWDM) with point-to-point wavelength division multiplexing (PtP WDM) overlay is proposed for the next-generation optical access networks in this paper. A novel software-defined optical distribution network (ODN) structure is designed based on wavelength selective switches (WSS), which can implement wavelength and bandwidth dynamical allocations and suits for the bursty traffic. The experimental results reveal that the TWDM-PON can provide 40 Gb/s downstream and 10 Gb/s upstream data transmission, while the PtP WDM-PON can support 10 GHz point-to-point dedicated bandwidth as the overlay complement system. The wavelengths of the TWDM-PON and PtP WDM-PON are allocated dynamically based on WSS, which verifies the feasibility of the proposed structure.

Survey of Airport Access Analysis Techniques - Models, Data and a Research Program

DOT National Transportation Integrated Search

1972-06-01

The report points up the differences and similarities between airport access travel and general urban trip making. Models and surveys developed for, or applicable, to airport access planning are reviewed. A research program is proposed which would ge...

Frequency Reconfigurable Antenna for Deca-Band 5 G/LTE/WWAN Mobile Terminal Applications

NASA Astrophysics Data System (ADS)

Yang, Lingsheng; Cheng, Biyu; Jia, Hongting

2018-04-01

In this paper, a frequency reconfigurable antenna for 5 G/LTE/WWAN mobile terminal applications is presented. The proposed antenna consists of a radiation element which is folded on a dielectric cuboid. Four PIN diodes located on the antenna element are used for frequency reconfigration. By controlling the states of four PIN diodes with an 8-bit microcontroller, a broad band which can cover deca-band as LTE700/2300/2500, GSM850/900/1800/1900, UMTS 2100, WLAN2400 and the future 5 G or LTE3600 is obtained with a compacted size of 40×8×5mm3. The antenna gain, efficiency and radiation characteristics are also shown.

Specific absorption rate analysis of broadband mobile antenna with negative index metamaterial

NASA Astrophysics Data System (ADS)

Alam, Touhidul; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

2016-03-01

This paper presents a negative index metamaterial-inspired printed mobile wireless antenna that can support most mobile applications such as GSM, UMTS, Bluetooth and WLAN frequency bands. The antenna consists of a semi-circular patch, a 50Ω microstrip feed line and metamaterial ground plane. The antenna occupies a very small space of 37 × 47 × 0.508 mm3, making it suitable for mobile wireless application. The perceptible novelty shown in this proposed antenna is that reduction of specific absorption rate using the negative index metamaterial ground plane. The proposed antenna reduced 72.11 and 75.53 % of specific absorption rate at 1.8 and 2.4 GHz, respectively.

76 FR 35880 - Combined Notice of Filings #1

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-20

... Hemingway Point to Point Agreements to be effective 6/1/ 2011. Filed Date: 06/13/2011. Accession Number.... Applicants: PacifiCorp. Description: PacifiCorp submits tariff filing per 35.15: Idaho Power Hemingway Point...

Artificial Water Point for Livestock Influences Spatial Ecology of a Native Lizard Species

PubMed Central

Leu, Stephan T.; Bull, C. Michael

2016-01-01

Pastoralism is a major agricultural activity in drier environments, and can directly and indirectly impact native species in those areas. We investigated how the supply of an artificial watering point to support grazing livestock affected movement and activity patterns of the Australian sleepy lizard (Tiliqua rugosa) during a drought year. We observed 23 adult lizards; six had access to a dam, whereas 17 lizards did not. Lizards with access to the dam had larger home ranges, were substantially active on more days (days with >100 steps), and moved more steps per day compared to lizards that did not have access to the dam, both during the early and late period of our observation. Furthermore, while the two groups of lizards had similar body condition early in the season, they differed later in the season. Lizards with dam access retained, whereas lizards without access lost body condition. Local heterogeneity in access to an artificial water resource resulted in spatially dependent behavioural variation among sleepy lizard individuals. This suggests that sleepy lizards have flexible responses to changing climatic conditions, depending on the availability of water. Furthermore, while reducing activity appears a suitable short term strategy, if harsh conditions persist, then access to dams could be of substantial benefit and could support sustained lizard activity and movement and allow maintenance of body condition. Hence, artificial watering points, such as the dams constructed by pastoralists, may provide local higher quality refugia for sleepy lizards and other species during drought conditions. PMID:26800274

Trajectory data privacy protection based on differential privacy mechanism

NASA Astrophysics Data System (ADS)

Gu, Ke; Yang, Lihao; Liu, Yongzhi; Liao, Niandong

2018-05-01

In this paper, we propose a trajectory data privacy protection scheme based on differential privacy mechanism. In the proposed scheme, the algorithm first selects the protected points from the user’s trajectory data; secondly, the algorithm forms the polygon according to the protected points and the adjacent and high frequent accessed points that are selected from the accessing point database, then the algorithm calculates the polygon centroids; finally, the noises are added to the polygon centroids by the differential privacy method, and the polygon centroids replace the protected points, and then the algorithm constructs and issues the new trajectory data. The experiments show that the running time of the proposed algorithms is fast, the privacy protection of the scheme is effective and the data usability of the scheme is higher.

Accessing the exceptional points of parity-time symmetric acoustics

PubMed Central

Shi, Chengzhi; Dubois, Marc; Chen, Yun; Cheng, Lei; Ramezani, Hamidreza; Wang, Yuan; Zhang, Xiang

2016-01-01

Parity-time (PT) symmetric systems experience phase transition between PT exact and broken phases at exceptional point. These PT phase transitions contribute significantly to the design of single mode lasers, coherent perfect absorbers, isolators, and diodes. However, such exceptional points are extremely difficult to access in practice because of the dispersive behaviour of most loss and gain materials required in PT symmetric systems. Here we introduce a method to systematically tame these exceptional points and control PT phases. Our experimental demonstration hinges on an active acoustic element that realizes a complex-valued potential and simultaneously controls the multiple interference in the structure. The manipulation of exceptional points offers new routes to broaden applications for PT symmetric physics in acoustics, optics, microwaves and electronics, which are essential for sensing, communication and imaging. PMID:27025443

Tracking Human Mobility Using WiFi Signals

PubMed Central

Sapiezynski, Piotr; Stopczynski, Arkadiusz; Gatej, Radu; Lehmann, Sune

2015-01-01

We study six months of human mobility data, including WiFi and GPS traces recorded with high temporal resolution, and find that time series of WiFi scans contain a strong latent location signal. In fact, due to inherent stability and low entropy of human mobility, it is possible to assign location to WiFi access points based on a very small number of GPS samples and then use these access points as location beacons. Using just one GPS observation per day per person allows us to estimate the location of, and subsequently use, WiFi access points to account for 80% of mobility across a population. These results reveal a great opportunity for using ubiquitous WiFi routers for high-resolution outdoor positioning, but also significant privacy implications of such side-channel location tracking. PMID:26132115

Hospitalization among migrants in Italy: Access to health care as an opportunity for integration and inclusion.

PubMed

Barsanti, Sara

2018-03-30

This paper analyzes migrant access to health care by comparing hospitalizations of native and immigrant population with respect the Tuscany Region (Italy). In the analyses, a critical gap both for legal and undocumented migrant population is highlighted. Indeed, we found some key differences between the migrant and native populations related to the use of specific hospital services in Tuscany and, indirectly, of community and primary care services. Moreover, especially for undocumented migrants, hospitals seem to be the only point of access to the health-care system for migrant populations. The results suggest that the Italian health-care system is unable to ensure an equitable access to health services. In this context, maternity care could be a key point of access to the welfare system that allows participation in the health system not only for mothers but also for all migrant family members. Copyright © 2018 John Wiley & Sons, Ltd.

15 CFR Appendix E to Subpart M of... - Motorized Personal Watercraft Zones and Access Routes Within the Sanctuary

Code of Federal Regulations, 2011 CFR

2011-01-01

... access route southwest along a bearing of approximately 196° true (180° magnetic) to the red and white...° magnetic) to the red and white bell buoy at the eastern boundary of Zone Three bounded by: Point ID No...° true (0° magnetic) to the southern boundary of Zone Four bounded by: Point ID No. Latitude Longitude 1...

Advanced Mobility Handover for Mobile IPv6 Based Wireless Networks

PubMed Central

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

2014-01-01

We propose an Advanced Mobility Handover scheme (AMH) in this paper for seamless mobility in MIPv6-based wireless networks. In the proposed scheme, the mobile node utilizes a unique home IPv6 address developed to maintain communication with other corresponding nodes without a care-of-address during the roaming process. The IPv6 address for each MN during the first round of AMH process is uniquely identified by HA using the developed MN-ID field as a global permanent, which is identifying uniquely the IPv6 address of MN. Moreover, a temporary MN-ID is generated by access point each time an MN is associated with a particular AP and temporarily saved in a developed table inside the AP. When employing the AMH scheme, the handover process in the network layer is performed prior to its default time. That is, the mobility handover process in the network layer is tackled by a trigger developed AMH message to the next access point. Thus, a mobile node keeps communicating with the current access point while the network layer handover is executed by the next access point. The mathematical analyses and simulation results show that the proposed scheme performs better as compared with the existing approaches. PMID:25614890

Changes in Self-reported Insurance Coverage, Access to Care, and Health Under the Affordable Care Act.

PubMed

Sommers, Benjamin D; Gunja, Munira Z; Finegold, Kenneth; Musco, Thomas

2015-07-28

The Affordable Care Act (ACA) completed its second open enrollment period in February 2015. Assessing the law's effects has major policy implications. To estimate national changes in self-reported coverage, access to care, and health during the ACA's first 2 open enrollment periods and to assess differences between low-income adults in states that expanded Medicaid and in states that did not expand Medicaid. Analysis of the 2012-2015 Gallup-Healthways Well-Being Index, a daily national telephone survey. Using multivariable regression to adjust for pre-ACA trends and sociodemographics, we examined changes in outcomes for the nonelderly US adult population aged 18 through 64 years (n = 507,055) since the first open enrollment period began in October 2013. Linear regressions were used to model each outcome as a function of a linear monthly time trend and quarterly indicators. Then, pre-ACA (January 2012-September 2013) and post-ACA (January 2014-March 2015) changes for adults with incomes below 138% of the poverty level in Medicaid expansion states (n = 48,905 among 28 states and Washington, DC) vs nonexpansion states (n = 37,283 among 22 states) were compared using a differences-in-differences approach. Beginning of the ACA's first open enrollment period (October 2013). Self-reported rates of being uninsured, lacking a personal physician, lacking easy access to medicine, inability to afford needed care, overall health status, and health-related activity limitations. Among the 507,055 adults in this survey, pre-ACA trends were significantly worsening for all outcomes. Compared with the pre-ACA trends, by the first quarter of 2015, the adjusted proportions who were uninsured decreased by 7.9 percentage points (95% CI, -9.1 to -6.7); who lacked a personal physician, -3.5 percentage points (95% CI, -4.8 to -2.2); who lacked easy access to medicine, -2.4 percentage points (95% CI, -3.3 to -1.5); who were unable to afford care, -5.5 percentage points (95% CI, -6.7 to -4.2); who reported fair/poor health, -3.4 percentage points (95% CI, -4.6 to -2.2); and the percentage of days with activities limited by health, -1.7 percentage points (95% CI, -2.4 to -0.9). Coverage changes were largest among minorities; for example, the decrease in the uninsured rate was larger among Latino adults (-11.9 percentage points [95% CI, -15.3 to -8.5]) than white adults (-6.1 percentage points [95% CI, -7.3 to -4.8]). Medicaid expansion was associated with significant reductions among low-income adults in the uninsured rate (differences-in-differences estimate, -5.2 percentage points [95% CI, -7.9 to -2.6]), lacking a personal physician (-1.8 percentage points [95% CI, -3.4 to -0.3]), and difficulty accessing medicine (-2.2 percentage points [95% CI, -3.8 to -0.7]). The ACA's first 2 open enrollment periods were associated with significantly improved trends in self-reported coverage, access to primary care and medications, affordability, and health. Low-income adults in states that expanded Medicaid reported significant gains in insurance coverage and access compared with adults in states that did not expand Medicaid.

Access to and Accessibility of Education: An Analytic and Conceptual Approach to a Multidimensional Issue

ERIC Educational Resources Information Center

Stauber, Barbara; Parreira do Amaral, Marcelo

2015-01-01

This article presents analytical considerations for the discussion of issues of access to education and inequality. It first sharpens the concept of access and inequality by pointing to the interplay of structure and agency as well as to processes of social differentiation in which differences are constructed. This implies a critical view on…

Maintaining the Access Mission: Open Access Universities and the Challenges of Performance-Based Funding

ERIC Educational Resources Information Center

Mathuews, Katy; Pulcini, Brad

2017-01-01

For the purposes of this article, open access universities are defined as bachelor's degree-granting institutions that do not restrict admission on the basis of ACT/SAT scores, high school grade point average, and the like. Typically, the mission of an open access university is to provide all students with the opportunity to pursue a degree. The…

How To Modify a Trailer for Accessibility (Up to a Point) [and] Accessibility Considerations for Home Buyers. Key Notes.

ERIC Educational Resources Information Center

Access Group, Atlanta, GA.

Two brief fact sheets for people with disabilities provide information on: (1) modifying a trailer to make it accessible for persons with mobility impairments, especially those in wheelchairs, and (2) accessibility considerations for home buyers or home owners with mobility impairments. The first fact sheet identifies inherent problems in…

The Association of Health Insurance with institutional delivery and access to skilled birth attendants: evidence from the Kenya Demographic and health survey 2008-09.

PubMed

Were, Lawrence P O; Were, Edwin; Wamai, Richard; Hogan, Joseph; Galarraga, Omar

2017-07-03

Healthcare financing through health insurance is gaining traction as developing countries strive to achieve universal health coverage and address the limited access to critical health services for specific populations including pregnant women and their children. However, these reforms are taking place despite limited evaluation of impact of health insurance on maternal health in developing countries including Kenya. In this study we evaluate the association of health insurance with access and utilization of obstetric delivery health services for pregnant women in Kenya. Nationally representative data from the Kenya Demographic and Health Survey 2008-09 was used in this study. 4082 pregnant women with outcomes of interest - Institutional delivery (Yes/No - delivery at hospital, dispensary, maternity home, and clinic) and access to skilled birth attendants (help by a nurse, doctor, or trained midwife at delivery) were selected from 8444 women ages 15-49 years. Linear and logistic regression, and propensity score adjustment are used to estimate the causal association of enrollment in insurance on obstetric health outcomes. Mothers with insurance are 23 percentage points (p < 0.01) more likely to deliver at an institution and 20 percentages points (p < 0.01) more likely have access to skilled birth attendants compared to those not insured. In addition mothers of lower socio-economic status benefit more from enrollment in insurance compared to mothers of higher socio-economic status. For both institutional delivery and access to skilled birth attendants, the average difference of the association of insurance enrollment compared to not enrolling for those of low SES is 23 percentage points (p < 0.01), and 6 percentage points (p < 0.01) for those of higher SES. Enrolling in health insurance is associated with increased access and utilization of obstetric delivery health services for pregnant women. Notably, those of lower socio-economic status seem to benefit the most from enrollment in insurance.

Flushing ports of totally implantable venous access devices, and impact of the Huber point needle bevel orientation: experimental tests and numerical computation.

PubMed

Guiffant, Gérard; Durussel, Jean Jacques; Flaud, Patrice; Vigier, Jean Pierre; Merckx, Jacques

2012-01-01

The use of totally implantable venous access devices developed as a medical device allowing mid- and long-term, frequent, repeated, or continuous injection of therapeutic products, by vascular, cavitary, or perineural access. The effective flushing of these devices is a central element to assure long-lasting use. Our experimental work demonstrates that directing the Huber point needle opening in the diametrically opposite direction of the implantable port exit channel increases the flushing efficiency. These results are consolidated by numerical computations, which support recommendations not only for their maintenance, but also for their use.

Flushing ports of totally implantable venous access devices, and impact of the Huber point needle bevel orientation: experimental tests and numerical computation

PubMed Central

Guiffant, Gérard; Durussel, Jean Jacques; Flaud, Patrice; Vigier, Jean Pierre; Merckx, Jacques

2012-01-01

The use of totally implantable venous access devices developed as a medical device allowing mid- and long-term, frequent, repeated, or continuous injection of therapeutic products, by vascular, cavitary, or perineural access. The effective flushing of these devices is a central element to assure long-lasting use. Our experimental work demonstrates that directing the Huber point needle opening in the diametrically opposite direction of the implantable port exit channel increases the flushing efficiency. These results are consolidated by numerical computations, which support recommendations not only for their maintenance, but also for their use. PMID:23166455

Technical Note [cmUse of a Snare Wire to Perform Nephrostomy Access in the Presence of Obstructive Staghorn Calculi

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nosher, John L.; Siegel, Randall L.; Bodner, Leonard J.

1996-05-15

We describe a technique for gaining access to the central collecting system via a chosen calyx, utilizing an alternative entry point to that calyx. An Amplatz nitinol loop snare is then used to convert this access to a traditional approach.

Improving the Accessibility and Efficiency of Point-of-Care Diagnostics Services in Low- and Middle-Income Countries: Lean and Agile Supply Chain Management.

PubMed

Kuupiel, Desmond; Bawontuo, Vitalis; Mashamba-Thompson, Tivani P

2017-11-29

Access to point-of-care (POC) diagnostics services is essential for ensuring rapid disease diagnosis, management, control, and surveillance. POC testing services can improve access to healthcare especially where healthcare infrastructure is weak and access to quality and timely medical care is a challenge. Improving the accessibility and efficiency of POC diagnostics services, particularly in resource-limited settings, may be a promising route to improving healthcare outcomes. In this review, the accessibility of POC testing is defined as the distance/proximity to the nearest healthcare facility for POC diagnostics service. This review provides an overview of the impact of POC diagnostics on healthcare outcomes in low- and middle-income countries (LMICs) and factors contributing to the accessibility of POC testing services in LMICs, focusing on characteristics of the supply chain management and quality systems management, characteristics of the geographical location, health infrastructure, and an enabling policy framework for POC diagnostics services. Barriers and challenges related to the accessibility of POC diagnostics in LMICs were also discussed. Bearing in mind the reported barriers and challenges as well as the disease epidemiology in LMICs, we propose a lean and agile supply chain management framework for improving the accessibility and efficiency of POC diagnostics services in these settings.

Improving the Accessibility and Efficiency of Point-of-Care Diagnostics Services in Low- and Middle-Income Countries: Lean and Agile Supply Chain Management

PubMed Central

Kuupiel, Desmond; Bawontuo, Vitalis

2017-01-01

Access to point-of-care (POC) diagnostics services is essential for ensuring rapid disease diagnosis, management, control, and surveillance. POC testing services can improve access to healthcare especially where healthcare infrastructure is weak and access to quality and timely medical care is a challenge. Improving the accessibility and efficiency of POC diagnostics services, particularly in resource-limited settings, may be a promising route to improving healthcare outcomes. In this review, the accessibility of POC testing is defined as the distance/proximity to the nearest healthcare facility for POC diagnostics service. This review provides an overview of the impact of POC diagnostics on healthcare outcomes in low- and middle-income countries (LMICs) and factors contributing to the accessibility of POC testing services in LMICs, focusing on characteristics of the supply chain management and quality systems management, characteristics of the geographical location, health infrastructure, and an enabling policy framework for POC diagnostics services. Barriers and challenges related to the accessibility of POC diagnostics in LMICs were also discussed. Bearing in mind the reported barriers and challenges as well as the disease epidemiology in LMICs, we propose a lean and agile supply chain management framework for improving the accessibility and efficiency of POC diagnostics services in these settings. PMID:29186013

Creating a Web-accessible, point-of-care, team-based information system (PointTIS): the librarian as publisher.

PubMed

Burrows, S C; Moore, K M; Lemkau, H L

2001-04-01

The Internet has created new opportunities for librarians to develop information systems that are readily accessible at the point of care. This paper describes the multiyear process used to justify, fund, design, develop, promote, and evaluate a rehabilitation prototype of a point-of-care, team-based information system (PoinTIS) and train health care providers to use this prototype for their spinal cord injury and traumatic brain injury patient care and education activities. PoinTIS is a successful model for librarians in the twenty-first century to serve as publishers of information created or used by their parent organizations and to respond to the opportunities for information dissemination provided by recent technological advances.

Prospective Durability Testing of a Vascular Access Phantom

DTIC Science & Technology

2010-09-01

ultrasound guidance when obtaining central venous access.19,20 The increasing use of ultrasound guidance for vascular access has created an educational...with difficult intravenous access. Ann Emerg Med. 2005;46:456-61. 7. Gallieni M, Cozzolino M. Uncomplicated central vein catheterization of high risk...al. Randomized, controlled clinical trial of point-of-care limited ultrasonography assistance of central venous cannulation: The third sonography

Point Cloud Storage and Access on a Global Scale

DTIC Science & Technology

2015-01-01

coordinates. These Geodetic values are appended to the list of parameters and are re-projected into WGS84 Geocentric (ECEF X,Y,Z), replacing the original...Append Lon,Lat,Alt to point parameters Re-project point with Proj.4 from Geodetic (Lon,Lat,Alt) -> Geocentric (X,Y,Z) Insert point into

50 CFR 660.70 - Groundfish conservation areas.

Code of Federal Regulations, 2011 CFR

2011-10-01

... points for the RCAs. (1) Trawl (Limited Entry and Open Access Nongroundfish Trawl Gears) Rockfish....71 through 660.74. (2) Non-Trawl (Limited Entry Fixed Gear and Open Access Non-trawl Gears) Rockfish...

Advanced Stent Graft Treatment of Venous Stenosis Affecting Hemodialysis Vascular Access: Case Illustrations

PubMed Central

Patel, Darshan; Ray, Charles E.; Lokken, R. Peter; Bui, James T.; Lipnik, Andrew J.; Gaba, Ron C.

2016-01-01

Surgically placed dialysis access is an important component of dialysis replacement therapy. The vast majority of patients undergoing dialysis will have surgically placed accesses at some point in the course of their disease, and for many patients these accesses may represent their definitive renal replacement option. Most, if not all, arteriovenous fistulae and grafts will require interventions at some point in time. Percutaneous angioplasty is the typical first treatment performed for venous stenoses, with stents and stent grafts being reserved for patients in whom angioplasty and surgical options are exhausted. In some salvage situations, stent graft placement may be the only or best option for patients. This article describes, using case illustrations, placement of stent grafts in such patients; a focus will also be made on the techniques utilized in such salvage situations. PMID:27011426

Embedding a randomized clinical trial into an ongoing registry infrastructure: unique opportunities for efficiency in design of the Study of Access site For Enhancement of Percutaneous Coronary Intervention for Women (SAFE-PCI for Women).

PubMed

Hess, Connie N; Rao, Sunil V; Kong, David F; Aberle, Laura H; Anstrom, Kevin J; Gibson, C Michael; Gilchrist, Ian C; Jacobs, Alice K; Jolly, Sanjit S; Mehran, Roxana; Messenger, John C; Newby, L Kristin; Waksman, Ron; Krucoff, Mitchell W

2013-09-01

Women are at higher risk than men for bleeding and vascular complications after percutaneous coronary intervention (PCI). Compared with femoral access, radial access reduces these complications but may be more challenging in women because of higher rates of radial artery spasm, tortuosity, and occlusion as well as lower rates of procedure success. Whether the safety advantages of radial versus femoral access in women undergoing PCI are outweighed by reduced effectiveness has not been studied. The Study of Access site For Enhancement of PCI for Women is a prospective, randomized clinical trial comparing radial with femoral arterial access in women undergoing PCI. In conjunction with the US Food and Drug Administration's Critical Path Cardiac Safety Research Consortium, this study embeds the randomized clinical trial into the existing infrastructure of the National Cardiovascular Data Registry CathPCI Registry through the National Institute of Health's National Cardiovascular Research Infrastructure. The primary efficacy end point is a composite of bleeding (Bleeding Academic Research Consortium types 2, 3, or 5) or vascular complication requiring intervention occurring at 72 hours after PCI or by hospital discharge. The primary feasibility end point is procedure success. Secondary end points include procedure duration, contrast volume, radiation dose, quality of life, and a composite of 30-day death, vascular complication, or unplanned revascularization. © 2013.

Child Health and Access to Medical Care

ERIC Educational Resources Information Center

Leininger, Lindsey; Levy, Helen

2015-01-01

It might seem strange to ask whether increasing access to medical care can improve children's health. Yet Lindsey Leininger and Helen Levy begin by pointing out that access to care plays a smaller role than we might think, and that many other factors, such as those discussed elsewhere in this issue, strongly influence children's health.…

Multi-modal two-step floating catchment area analysis of primary health care accessibility.

PubMed

Langford, Mitchel; Higgs, Gary; Fry, Richard

2016-03-01

Two-step floating catchment area (2SFCA) techniques are popular for measuring potential geographical accessibility to health care services. This paper proposes methodological enhancements to increase the sophistication of the 2SFCA methodology by incorporating both public and private transport modes using dedicated network datasets. The proposed model yields separate accessibility scores for each modal group at each demand point to better reflect the differential accessibility levels experienced by each cohort. An empirical study of primary health care facilities in South Wales, UK, is used to illustrate the approach. Outcomes suggest the bus-riding cohort of each census tract experience much lower accessibility levels than those estimated by an undifferentiated (car-only) model. Car drivers' accessibility may also be misrepresented in an undifferentiated model because they potentially profit from the lower demand placed upon service provision points by bus riders. The ability to specify independent catchment sizes for each cohort in the multi-modal model allows aspects of preparedness to travel to be investigated. Copyright © 2016. Published by Elsevier Ltd.

Access Point Selection for Multi-Rate IEEE 802.11 Wireless LANs

DTIC Science & Technology

2014-05-16

Mobile Systems, Applications and Services, 2006. [2] S . Vasudevan, K. Papagiannaki, C . Diot, J. Kurose, and D. Towsley, “Facilitating Access Point...LANs 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7...PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) University of California at Berkeley,Electrical Engineering and Computer Sciences,Berkeley,CA,94720 8

Final Environmental Impact Statement Relating to the Operation and Maintenance of the Fox River, Wisconsin Navigation Project.

DTIC Science & Technology

1977-05-01

Department of Biology University of Wisconsin-Oshkosh Johnathon P. Ela Oshkosh, Wisconsin 54901 Sierra Club, Midwest Office 444 West Main, Rm 10 Water... Indiana and more distant are,a. Access points are fairly well distributed around the various lakes and pools and provide convenient access points for...Illinois and Indiana . Although U. S. Coast Guard statistics are not available for recreational boating accidents on Lake Winnebago, it is presumed that

A compact 5.5 GHz band-rejected UWB antenna using complementary split ring resonators.

PubMed

Islam, M M; Faruque, M R I; Islam, M T

2014-01-01

A band-removal property employing microwave frequencies using complementary split ring resonators (CSRRs) is applied to design a compact UWB antenna wishing for the rejection of some frequency band, which is meanwhile exercised by the existing wireless applications. The reported antenna comprises optimization of a circular radiating patch, in which slotted complementary SRRs are implanted. It is printed on low dielectric FR4 substrate material fed by a partial ground plane and a microstrip line. Validated results exhibit that the reported antenna shows a wide bandwidth covering from 3.45 to more than 12 GHz, with a compact dimension of 22 × 26 mm(2), and VSWR < 2, observing band elimination of 5.5 GHz WLAN band.

Semantically Enriched Data Access Policies in eHealth.

PubMed

Drozdowicz, Michał; Ganzha, Maria; Paprzycki, Marcin

2016-11-01

Internet of Things (IoT) requires novel solutions to facilitate autonomous, though controlled, resource access. Access policies have to facilitate interactions between heterogeneous entities (devices and humans). Here, we focus our attention on access control in eHealth. We propose an approach based on enriching policies, based on well-known and widely-used eXtensible Access Control Markup Language, with semantics. In the paper we describe an implementation of a Policy Information Point integrated with the HL7 Security and Privacy Ontology.

Performance evaluation of modulation and multiple access schemes in ultraviolet optical wireless connections for two atmosphere thickness cases.

PubMed

Raptis, Nikos; Pikasis, Evangelos; Syvridis, Dimitris

2016-08-01

The exploitation of optical wireless communication channels in a non-line-of-sight regime is studied for point-to-point and networking configurations considering the use of light-emitting diodes. Two environments with different scattering center densities are considered, assuming operation at 265 nm. The bit error rate performance of both pulsed and multicarrier modulation schemes is examined, using numerical approaches. In the networking scenario, a central node only receives data, one node transmits useful data, and the rest of them act as interferers. The performance of the desirable node's transmissions is evaluated. The access to the medium is controlled by a code division multiple access scheme.

Apollo: Giving application developers a single point of access to public health models using structured vocabularies and Web services

PubMed Central

Wagner, Michael M.; Levander, John D.; Brown, Shawn; Hogan, William R.; Millett, Nicholas; Hanna, Josh

2013-01-01

This paper describes the Apollo Web Services and Apollo-SV, its related ontology. The Apollo Web Services give an end-user application a single point of access to multiple epidemic simulators. An end user can specify an analytic problem—which we define as a configuration and a query of results—exactly once and submit it to multiple epidemic simulators. The end user represents the analytic problem using a standard syntax and vocabulary, not the native languages of the simulators. We have demonstrated the feasibility of this design by implementing a set of Apollo services that provide access to two epidemic simulators and two visualizer services. PMID:24551417

Apollo: giving application developers a single point of access to public health models using structured vocabularies and Web services.

PubMed

Wagner, Michael M; Levander, John D; Brown, Shawn; Hogan, William R; Millett, Nicholas; Hanna, Josh

2013-01-01

This paper describes the Apollo Web Services and Apollo-SV, its related ontology. The Apollo Web Services give an end-user application a single point of access to multiple epidemic simulators. An end user can specify an analytic problem-which we define as a configuration and a query of results-exactly once and submit it to multiple epidemic simulators. The end user represents the analytic problem using a standard syntax and vocabulary, not the native languages of the simulators. We have demonstrated the feasibility of this design by implementing a set of Apollo services that provide access to two epidemic simulators and two visualizer services.

Fixed-Rate Compressed Floating-Point Arrays.

PubMed

Lindstrom, Peter

2014-12-01

Current compression schemes for floating-point data commonly take fixed-precision values and compress them to a variable-length bit stream, complicating memory management and random access. We present a fixed-rate, near-lossless compression scheme that maps small blocks of 4(d) values in d dimensions to a fixed, user-specified number of bits per block, thereby allowing read and write random access to compressed floating-point data at block granularity. Our approach is inspired by fixed-rate texture compression methods widely adopted in graphics hardware, but has been tailored to the high dynamic range and precision demands of scientific applications. Our compressor is based on a new, lifted, orthogonal block transform and embedded coding, allowing each per-block bit stream to be truncated at any point if desired, thus facilitating bit rate selection using a single compression scheme. To avoid compression or decompression upon every data access, we employ a software write-back cache of uncompressed blocks. Our compressor has been designed with computational simplicity and speed in mind to allow for the possibility of a hardware implementation, and uses only a small number of fixed-point arithmetic operations per compressed value. We demonstrate the viability and benefits of lossy compression in several applications, including visualization, quantitative data analysis, and numerical simulation.

7 CFR 1739.3 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... building with at least ten (10) Computer Access Points, that is used for the purposes of providing free access to and/or instruction in the use of broadband Internet service, and is of the appropriate size to...

7 CFR 1739.3 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... building with at least ten (10) Computer Access Points, that is used for the purposes of providing free access to and/or instruction in the use of broadband Internet service, and is of the appropriate size to...

Safety Benefits of Access Spacing

DOT National Transportation Integrated Search

1997-01-01

The spacing of driveways and streets is an important element in roadway planning, design, and operation. Access points are the main source of accidents and congestion. Their location and spacing affects the safety and functional integrity of streets ...

Toxic Release Inventory (TRI) (2017 EIC)

EPA Pesticide Factsheets

Focusing on air releases, explore tried and true access points along with new ways to access the data including the new P2 tool (currently available) and the TRI Analyzer tool (schedule to go public summer 2015)

Effect of Pointing Error on the BER Performance of an Optical CDMA FSO Link with SIK Receiver

NASA Astrophysics Data System (ADS)

Nazrul Islam, A. K. M.; Majumder, S. P.

2017-12-01

An analytical approach is presented for an optical code division multiple access (OCDMA) system over free space optical (FSO) channel considering the effect of pointing error between the transmitter and the receiver. Analysis is carried out with an optical sequence inverse keying (SIK) correlator receiver with intensity modulation and direct detection (IM/DD) to find the bit error rate (BER) with pointing error. The results are evaluated numerically in terms of signal-to-noise plus multi-access interference (MAI) ratio, BER and power penalty due to pointing error. It is noticed that the OCDMA FSO system is highly affected by pointing error with significant power penalty at a BER of 10-6 and 10-9. For example, penalty at BER 10-9 is found to be 9 dB corresponding to normalized pointing error of 1.4 for 16 users with processing gain of 256 and is reduced to 6.9 dB when the processing gain is increased to 1,024.

Access to point-of-care tests reduces the prescription of antibiotics among antibiotic-requesting subjects with respiratory tract infections.

PubMed

Llor, Carl; Bjerrum, Lars; Munck, Anders; Cots, Josep M; Hernández, Silvia; Moragas, Ana

2014-12-01

General practitioners (GPs) often feel uncomfortable when patients request an antibiotic when there is likely little benefit. This study evaluates the effect of access to point-of-care tests on decreasing the prescription of antibiotics in respiratory tract infections in subjects who explicitly requested an antibiotic prescription. Spanish GPs registered all cases of respiratory tract infections over a 3-week period before and after an intervention undertaken in 2008 and 2009. Patients with acute sinusitis, pneumonia, and exacerbations of COPD were excluded. Two types of interventions were performed: the full intervention group received prescriber feedback with discussion of the results of the first registry, courses for GPs, guidelines, patient information leaflets, workshops, and access to point-of-care tests (rapid streptococcal antigen detection test and C-reactive protein test); and the partial intervention group underwent all of the above interventions except for the workshop and access to point-of-care tests. A total of 210 GPs were assigned to the full intervention group and 71 to the partial intervention group. A total of 25,479 subjects with respiratory tract infections were included, of whom 344 (1.4%) requested antibiotic prescribing. Antibiotics were more frequently prescribed to subjects requesting them compared with those who did not (49.1% vs 18.5%, P < .001). In the group of GPs assigned to the partial intervention group, 53.1% of subjects requesting antibiotics received a prescription before and 60% after the intervention, without statistical differences being observed. In the group of GPs assigned to the full intervention group, the percentages were 55.1% and 36.2%, respectively, with a difference of 18.9% (95% CI: 6.4%-30.6%, P < .05). Access to point-of-care tests reduces antibiotic use in subjects who explicitly request an antibiotic prescription. Copyright © 2014 by Daedalus Enterprises.

A Two-Wave Observational Study of Compliance With Youth Access and Tobacco Advertising Provisions of the Cigarettes and Other Tobacco Products Act in India.

PubMed

Mead, Erin L; Rimal, Rajiv N; Cohen, Joanna E; Turner, Monique M; Lumby, Elena C; Feighery, Ellen C; Shah, Vandana

2016-05-01

The Indian Cigarettes and Other Tobacco Products Act prohibits youths' access to tobacco products at points-of-sale and near educational institutions, requires signage stating these restrictions in these venues, and bans outdoor advertisements. This observational study examined compliance with these provisions, changes in compliance over 1 year, and factors associated with compliance. Data were collected in 2012 and 2013 from points-of-sale (n = 555 in 2012, n = 718 in 2013), educational institutions (n = 277 in 2012, n = 276 in 2013), and neighborhoods (n = 104 in 2012, n = 125 in 2013) in 25 urban and rural towns in five states. Compliance across years was compared using chi-square tests. Multilevel regression equations assessed factors associated with compliance at Wave 2 and change in compliance from Wave 1 to Wave 2. Most points-of-sale had no/low compliance, with little change over time (58% to 63%, P = .108). The proportion of educational institutions observing just 1-2 provisions increased (39% to 52%, P = .002). Most neighborhoods complied with the advertisement ban at both waves (91% to 96%, P = .172). In the multilevel analysis, point-of-sale compliance increased in small cities; compliance decreased at points-of-sale and increased at institutions in mid-sized cities. Changes in point-of-sale compliance were due to compliance with access restrictions and signage requirements; changes in educational institution compliance were due to compliance with the sales ban. Compliance with provisions regarding the sale and display of tobacco products is moderate, while compliance with the advertisement ban remains high in these five Indian states. Greater enforcement will further reduce youths' exposure to tobacco products. The study adds to the literature on compliance and changes in compliance with policy to prohibit youth access to tobacco products in India, a country that has large geographic disparities in youth smoking prevalence. The findings highlight several important areas on which efforts can focus to improve compliance among points-of-sale, educations institutions, and neighborhoods to limit youths' exposure and access to tobacco products. Rural areas and large cities in particular need more concerted efforts. © The Author 2015. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A Two-Wave Observational Study of Compliance With Youth Access and Tobacco Advertising Provisions of the Cigarettes and Other Tobacco Products Act in India

PubMed Central

Rimal, Rajiv N.; Cohen, Joanna E.; Turner, Monique M.; Lumby, Elena C.; Feighery, Ellen C.; Shah, Vandana

2016-01-01

Abstract Introduction: The Indian Cigarettes and Other Tobacco Products Act prohibits youths’ access to tobacco products at points-of-sale and near educational institutions, requires signage stating these restrictions in these venues, and bans outdoor advertisements. This observational study examined compliance with these provisions, changes in compliance over 1 year, and factors associated with compliance. Methods: Data were collected in 2012 and 2013 from points-of-sale ( n = 555 in 2012, n = 718 in 2013), educational institutions ( n = 277 in 2012, n = 276 in 2013), and neighborhoods ( n = 104 in 2012, n = 125 in 2013) in 25 urban and rural towns in five states. Compliance across years was compared using chi-square tests. Multilevel regression equations assessed factors associated with compliance at Wave 2 and change in compliance from Wave 1 to Wave 2. Results: Most points-of-sale had no/low compliance, with little change over time (58% to 63%, P = .108). The proportion of educational institutions observing just 1–2 provisions increased (39% to 52%, P = .002). Most neighborhoods complied with the advertisement ban at both waves (91% to 96%, P = .172). In the multilevel analysis, point-of-sale compliance increased in small cities; compliance decreased at points-of-sale and increased at institutions in mid-sized cities. Changes in point-of-sale compliance were due to compliance with access restrictions and signage requirements; changes in educational institution compliance were due to compliance with the sales ban. Conclusions: Compliance with provisions regarding the sale and display of tobacco products is moderate, while compliance with the advertisement ban remains high in these five Indian states. Greater enforcement will further reduce youths’ exposure to tobacco products. Implications: The study adds to the literature on compliance and changes in compliance with policy to prohibit youth access to tobacco products in India, a country that has large geographic disparities in youth smoking prevalence. The findings highlight several important areas on which efforts can focus to improve compliance among points-of-sale, educations institutions, and neighborhoods to limit youths’ exposure and access to tobacco products. Rural areas and large cities in particular need more concerted efforts. PMID:26610937

Global Access to Library of Congress' Digital Resources: National Digital Library and Internet Resources.

ERIC Educational Resources Information Center

Chen, Ching-chih

1996-01-01

Summarizes how the Library of Congress' digital library collections can be accessed globally via the Internet and World Wide Web. Outlines the resources found in each of the various access points: gopher, online catalog, library and legislative Web sites, legal and copyright databases, and FTP (file transfer protocol) sites. (LAM)

Publishing Accessible Materials on the Web and CD-ROM.

ERIC Educational Resources Information Center

Federal Resource Center for Special Education, Washington, DC.

While it is generally simple to make electronic content accessible, it is also easy inadvertently to make it inaccessible. This guide covers the many formats of electronic documents and points out what to keep in mind and what procedures to follow to make documents accessible to all when disseminating information via the World Wide Web and on…

System Design and Cataloging Meet the User: User Interfaces to Online Public Access Catalogs.

ERIC Educational Resources Information Center

Yee, Martha M.

1991-01-01

Discusses features of online public access catalogs: (1) demonstration of relationships between records; (2) provision of entry vocabularies; (3) arrangement of multiple entries on the screen; (4) provision of access points; (5) display of single records; and (6) division of catalogs into separate files or indexes. User studies and other research…

Starting Point: Pedagogic Resources for Teaching and Learning Economics

ERIC Educational Resources Information Center

Maier, Mark H.; McGoldrick, KimMarie; Simkins, Scott P.

2012-01-01

This article describes Starting Point: Teaching and Learning Economics, a Web-based portal that makes innovative pedagogic resources and effective teaching practices easily accessible to economists. Starting Point introduces economists to teaching innovations through 16 online modules, each containing a general description of a specific pedagogic…

Toxic Release Inventory Training Course (TRI) (2015 EIC)

EPA Pesticide Factsheets

Focusing on air releases, explore tried and true access points along with new ways to access the data including the new P2 tool (currently available) and the TRI Analyzer tool (schedule to go public summer 2015)

41 CFR 101-28.306-5 - Safeguards.

Code of Federal Regulations, 2013 CFR

2013-07-01

... will not change the ship-to location associated with the customer access code except upon receipt of a... these access codes that orders are accepted by the CSC and these codes determine the ship-to points for...

41 CFR 101-28.306-5 - Safeguards.

Code of Federal Regulations, 2012 CFR

2012-07-01

... will not change the ship-to location associated with the customer access code except upon receipt of a... these access codes that orders are accepted by the CSC and these codes determine the ship-to points for...

41 CFR 101-28.306-5 - Safeguards.

Code of Federal Regulations, 2014 CFR

2014-07-01

... will not change the ship-to location associated with the customer access code except upon receipt of a... these access codes that orders are accepted by the CSC and these codes determine the ship-to points for...

MyEnviroMapper

EPA Pesticide Factsheets

EnviroMapper for Envirofacts is a single point of access to select U.S. EPA environmental data. This Web site provides access to several EPA databases to provide you with information about environmental activities that may affect air, water, and l

Leveraging the U.S. Criminal Justice System to Access Women for HIV Interventions.

PubMed

Meyer, Jaimie P; Muthulingam, Dharushana; El-Bassel, Nabila; Altice, Frederick L

2017-12-01

The criminal justice (CJ) system can be leveraged to access women for HIV prevention and treatment programs. Research is lacking on effective implementation strategies tailored to the specific needs of CJ-involved women. We conducted a scoping review of published studies in English from the United States that described HIV interventions, involved women or girls, and used the CJ system as an access point for sampling or intervention delivery. We identified 350 studies and synthesized data from 42 unique interventions, based in closed (n = 26), community (n = 7), or multiple/other CJ settings (n = 9). A minority of reviewed programs incorporated women-specific content or conducted gender-stratified analyses. CJ systems are comprised of diverse access points, each with unique strengths and challenges for implementing HIV treatment and prevention programs for women. Further study is warranted to develop women-specific and trauma-informed content and evaluate program effectiveness.

Do open access data policies inhibit innovation?

USGS Publications Warehouse

Katzner, Todd E.

2015-01-01

There has been a great deal of attention paid recently to the idea of data sharing (Van Noorden 2014, Beardsley 2015, Nature Publishing Group2015, www.copdess.com). However, the vast majority of these arguments are in agreement and present as fait accompli the idea that data are a public good and that therefore, once published, they should become open access. In fact, although there are many good reasons for data sharing, there also are a number of cogent and coherent cases to be made against open-access policies (e.g., Fenichel and Skelly 2015). The goal of this piece is not to debate the relevance or accuracy of the points made in favor of data sharing but to elevate the discussion by pointing out key problems with open-access policies and to identify central issues that, if solved, will enhance the utility of data sharing to science and society.

Evidence-Based Practice Point-of-Care Resources: A Quantitative Evaluation of Quality, Rigor, and Content.

PubMed

Campbell, Jared M; Umapathysivam, Kandiah; Xue, Yifan; Lockwood, Craig

2015-12-01

Clinicians and other healthcare professionals need access to summaries of evidence-based information in order to provide effective care to their patients at the point-of-care. Evidence-based practice (EBP) point-of-care resources have been developed and are available online to meet this need. This study aimed to develop a comprehensive list of available EBP point-of-care resources and evaluate their processes and policies for the development of content, in order to provide a critical analysis based upon rigor, transparency and measures of editorial quality to inform healthcare providers and promote quality improvement amongst publishers of EBP resources. A comprehensive and systematic search (Pubmed, CINAHL, and Cochrane Central) was undertaken to identify available EBP point-of-care resources, defined as "web-based medical compendia specifically designed to deliver predigested, rapidly accessible, comprehensive, periodically updated, and evidence-based information (and possibly also guidance) to clinicians." A pair of investigators independently extracted information on general characteristics, content presentation, editorial quality, evidence-based methodology, and breadth and volume. Twenty-seven summary resources were identified, of which 22 met the predefined inclusion criteria for EBP point-of-care resources, and 20 could be accessed for description and assessment. Overall, the upper quartile of EBP point-of-care providers was assessed to be UpToDate, Nursing Reference Centre, Mosby's Nursing Consult, BMJ Best Practice, and JBI COnNECT+. The choice of which EBP point-of-care resources are suitable for an organization is a decision that depends heavily on the unique requirements of that organization and the resources it has available. However, the results presented in this study should enable healthcare providers to make that assessment in a clear, evidence-based manner, and provide a comprehensive list of the available options. © 2015 Sigma Theta Tau International.

1. Context view shows approach of access road to summit, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Context view shows approach of access road to summit, communication towers and NW corner of lookout tower at center right. Camera is pointed SE. - Chelan Butte Lookout, Summit of Chelan Butte, Chelan, Chelan County, WA

Decorrelation of the static and dynamic length scales in hard-sphere glass formers.

PubMed

Charbonneau, Patrick; Tarjus, Gilles

2013-04-01

We show that, in the equilibrium phase of glass-forming hard-sphere fluids in three dimensions, the static length scales tentatively associated with the dynamical slowdown and the dynamical length characterizing spatial heterogeneities in the dynamics unambiguously decorrelate. The former grow at a much slower rate than the latter when density increases. This observation is valid for the dynamical range that is accessible to computer simulations, which roughly corresponds to that accessible in colloidal experiments. We also find that, in this same range, no one-to-one correspondence between relaxation time and point-to-set correlation length exists. These results point to the coexistence of several relaxation mechanisms in the dynamically accessible regime of three-dimensional hard-sphere glass formers.

Beyond Section 508: The Spectrum of Legal Requirements for Accessible e-Government Web Sites in the United States

ERIC Educational Resources Information Center

Jaeger, Paul T.

2004-01-01

In the United States, a number of federal laws establish requirements that electronic government (e-government) information and services be accessible to individuals with disabilities. These laws affect e-government Web sites at the federal, state, and local levels. To this point, research about the accessibility of e-government Web sites has…

Who Gets What? Is Improved Access to Basic Education Pro-Poor in Sub-Saharan Africa?

ERIC Educational Resources Information Center

Lewin, Keith M.; Sabates, Ricardo

2012-01-01

This paper explores changing patterns of access to basic education in six Sub-Saharan Africa countries using data from Demographic and Health Surveys at two points in time. In general the analysis confirms that participation of children in schooling has increased over the last decade. However, access to education remains strongly associated with…

New Technology and Digital Worlds: Analyzing Evidence of Equity in Access, Use, and Outcomes

ERIC Educational Resources Information Center

Warschauer, Mark; Matuchniak, Tina

2010-01-01

In this chapter, the authors take a broad perspective on how to analyze issues of technology and equity for youth in the United States. They begin with "access" as a starting point, but consider not only whether diverse groups of youth have digital media available to them but also how that access is supported or constrained by…

On-line access to geoscience bibliographic citations

USGS Publications Warehouse

Wild, Emily C.

2012-01-01

On-line geoscience bibliographic citations and access points to citations are exponentially increasing as commercial, non-profit, and government agencies worldwide publish materials electronically. On-line bibliographic tools capture cited works, and open access content allows for freely obtained citations and documents. For this newsletter, citations from the numerous journals and books listed in the "Recent Papers" section of the EXPLORE newsletters from 2008-2011 were used to provide freely-accessible web sites to determine the availability of bibliographic information.

Household water insecurity and its cultural dimensions: preliminary results from Newtok, Alaska.

PubMed

Eichelberger, Laura

2017-06-21

Using a relational approach, I examine several cultural dimensions involved in household water access and use in Newtok, Alaska. I describe the patterns that emerge around domestic water access and use, as well as the subjective lived experiences of water insecurity including risk perceptions, and the daily work and hydro-social relationships involved in accessing water from various sources. I found that Newtok residents haul water in limited amounts from a multitude of sources, both treated and untreated, throughout the year. Household water access is tied to hydro-social relationships predicated on sharing and reciprocity, particularly when the primary treated water access point is unavailable. Older boys and young men are primarily responsible for hauling water, and this role appears to be important to male Yupik identity. Many interviewees described preferring to drink untreated water, a practice that appears related to cultural constructions of natural water sources as pure and self-purifying, as well as concerns about the safety of treated water. Concerns related to the health consequences of low water access appear to differ by gender and age, with women and elders expressing greater concern than men. These preliminary results point to the importance of understanding the cultural dimensions involved in household water access and use. I argue that institutional responses to water insecurity need to incorporate such cultural dimensions into solutions aimed at increasing household access to and use of water.

Latin Hypercube Sampling (LHS) at variable resolutions for enhanced watershed scale Soil Sampling and Digital Soil Mapping.

NASA Astrophysics Data System (ADS)

Hamalainen, Sampsa; Geng, Xiaoyuan; He, Juanxia

2017-04-01

Latin Hypercube Sampling (LHS) at variable resolutions for enhanced watershed scale Soil Sampling and Digital Soil Mapping. Sampsa Hamalainen, Xiaoyuan Geng, and Juanxia, He. AAFC - Agriculture and Agr-Food Canada, Ottawa, Canada. The Latin Hypercube Sampling (LHS) approach to assist with Digital Soil Mapping has been developed for some time now, however the purpose of this work was to complement LHS with use of multiple spatial resolutions of covariate datasets and variability in the range of sampling points produced. This allowed for specific sets of LHS points to be produced to fulfil the needs of various partners from multiple projects working in the Ontario and Prince Edward Island provinces of Canada. Secondary soil and environmental attributes are critical inputs that are required in the development of sampling points by LHS. These include a required Digital Elevation Model (DEM) and subsequent covariate datasets produced as a result of a Digital Terrain Analysis performed on the DEM. These additional covariates often include but are not limited to Topographic Wetness Index (TWI), Length-Slope (LS) Factor, and Slope which are continuous data. The range of specific points created in LHS included 50 - 200 depending on the size of the watershed and more importantly the number of soil types found within. The spatial resolution of covariates included within the work ranged from 5 - 30 m. The iterations within the LHS sampling were run at an optimal level so the LHS model provided a good spatial representation of the environmental attributes within the watershed. Also, additional covariates were included in the Latin Hypercube Sampling approach which is categorical in nature such as external Surficial Geology data. Some initial results of the work include using a 1000 iteration variable within the LHS model. 1000 iterations was consistently a reasonable value used to produce sampling points that provided a good spatial representation of the environmental attributes. When working within the same spatial resolution for covariates, however only modifying the desired number of sampling points produced, the change of point location portrayed a strong geospatial relationship when using continuous data. Access to agricultural fields and adjacent land uses is often "pinned" as the greatest deterrent to performing soil sampling for both soil survey and soil attribute validation work. The lack of access can be a result of poor road access and/or difficult geographical conditions to navigate for field work individuals. This seems a simple yet continuous issue to overcome for the scientific community and in particular, soils professionals. The ability to assist with the ease of access to sampling points will be in the future a contribution to the Latin Hypercube Sampling (LHS) approach. By removing all locations in the initial instance from the DEM, the LHS model can be restricted to locations only with access from the adjacent road or trail. To further the approach, a road network geospatial dataset can be included within spatial Geographic Information Systems (GIS) applications to access already produced points using a shortest-distance network method.

FTTH: the overview of existing technologies

NASA Astrophysics Data System (ADS)

Nowak, Dawid; Murphy, John

2005-06-01

The growing popularity of the Internet is the key driver behind the development of new access methods which would enable a customer to experience a true broadband. Amongst various technologies, the access methods based on the optical fiber are getting more and more attention as they offer the ultimate solution in delivering different services to the customers' premises. Three different architectures have been proposed that facilitate the roll out of Fiber-to-the-Home (FTTH) infrastructure. Point-to-point Ethernet networks are the most straightforward and already matured solution. Different flavors of Passive Optical Networks (PONs) with Time Division Multiplexing Access (TDMA) are getting more widespread as necessary equipment is becoming available on the market. The third main contender are PONs withWavelength DivisionMultiplexing Access (WDMA). Although still in their infancy, the laboratory tests show that they have many advantages over present solutions. In this paper we show a brief comparison of these three access methods. In our analysis the architecture of each solution is presented. The applicability of each system is looked at from different viewpoint and their advantages and disadvantages are highlighted.

Wlan-Based Indoor Localization Using Neural Networks

NASA Astrophysics Data System (ADS)

Saleem, Fasiha; Wyne, Shurjeel

2016-07-01

Wireless indoor localization has generated recent research interest due to its numerous applications. This work investigates Wi-Fi based indoor localization using two variants of the fingerprinting approach. Specifically, we study the application of an artificial neural network (ANN) for implementing the fingerprinting approach and compare its localization performance with a probabilistic fingerprinting method that is based on maximum likelihood estimation (MLE) of the user location. We incorporate spatial correlation of fading into our investigations, which is often neglected in simulation studies and leads to erroneous location estimates. The localization performance is quantified in terms of accuracy, precision, robustness, and complexity. Multiple methods for handling the case of missing APs in online stage are investigated. Our results indicate that ANN-based fingerprinting outperforms the probabilistic approach for all performance metrics considered in this work.

A Compact 5.5 GHz Band-Rejected UWB Antenna Using Complementary Split Ring Resonators

PubMed Central

Islam, M. M.; Faruque, M. R. I.; Islam, M. T.

2014-01-01

A band-removal property employing microwave frequencies using complementary split ring resonators (CSRRs) is applied to design a compact UWB antenna wishing for the rejection of some frequency band, which is meanwhile exercised by the existing wireless applications. The reported antenna comprises optimization of a circular radiating patch, in which slotted complementary SRRs are implanted. It is printed on low dielectric FR4 substrate material fed by a partial ground plane and a microstrip line. Validated results exhibit that the reported antenna shows a wide bandwidth covering from 3.45 to more than 12 GHz, with a compact dimension of 22 × 26 mm2, and VSWR < 2, observing band elimination of 5.5 GHz WLAN band. PMID:24971379

Low-SAR metamaterial-inspired printed monopole antenna

NASA Astrophysics Data System (ADS)

Hossain, M. I.; Faruque, M. R. I.; Islam, M. T.; Ali, M. T.

2017-01-01

In this paper, a low-SAR metamaterial-embedded planar monopole antenna is introduced for a wireless communication system. A printed monopole antenna is designed for modern mobile, which operates in GSM, UMTS, LTE, WLAN, and Bluetooth frequency bands. A metamaterial structure is designed to use in the mobile handset with a multi-band printed monopole antenna. The finite integration technique of the CST microwave studio is used in this study. The measurement of antenna performances is taken in an anechoic chamber, and the SAR values are measured using COMOSAR system. The results indicate that metamaterial structure leads to reduce SAR without affecting antenna performance significantly. According to the measured results, the metamaterial attachment leads to reduce 87.7% peak SAR, 68.2% 1-g SAR, and 46.78% 10-g SAR compared to antenna without metamaterial.

77 FR 31851 - Privacy Act System of Records

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-30

... identification, U.S. visa number, FCC point of contact, visitor signature, professional title, organizational... pertinent records, or to another public authority or professional organization, if necessary to obtain... secured by limited access card readers. The computer servers themselves are password-protected. Access to...

What's in Your Techno-Future? Vendors Share Their Views.

ERIC Educational Resources Information Center

Gerber, Carole

1995-01-01

Examines vendors' views on the future of CD-ROM technology. Topics include the library role, single point access, costs, tape backup, user-friendly library automation systems and databases, improved quality, the growth of Internet access, and perspectives on technology in schools. (AEF)

Self-Reported Barriers to Healthcare Access for Rheumatoid Arthritis Patients in Rural and Northern Saskatchewan: A Mixed Methods Study.

PubMed

Nair, B V; Schuler, R; Stewart, S; Taylor-Gjevre, R M

2016-12-01

The aim of the present study was to identify potential barriers for access to medical and allied health services from the perspective of rural and Northern Saskatchewan rheumatoid arthritis (RA) patients. A total of 100 adults with established RA, residing in rural and Northern Saskatchewan, were recruited from two rheumatology practices. Structured interviews with standardized scripts solicited patient perspectives on appointment waiting times, travel required to access medical services and satisfaction with healthcare provision. Thematic analysis was employed for qualitative data. Patients-reported concerns regarding waiting time for their first rheumatology appointment. There was reduced access to allied health professionals, with only 53% of the participants having seen a physiotherapist (PT), and only 26% an occupational therapist (OT). Patients had similar driving distances to their family physician, PT, pharmacy and laboratory services but commuted significantly further for rheumatologist and OT services. There were high levels of satisfaction with their rheumatologist and family physician appointments (8.96 and 8.04 on a ten-point scale). Patients with longer travel times had higher satisfaction with their health care appointments: Patients who travelled one, two and more than two hours had satisfaction scores of 0.93, 0.88 and 1.32 points higher on a ten-point scale (p < 0.03). Access to medical services is a concern for this population. Patients were dissatisfied with the waiting time for their first specialist appointment and with decreased access to allied health professionals. Patients travelling longer distances were more satisfied with their health care provider's care, suggesting that good patient-care giver relationships helped to ameliorate the difficulties of travelling to their appointments. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Real-time video streaming in mobile cloud over heterogeneous wireless networks

NASA Astrophysics Data System (ADS)

Abdallah-Saleh, Saleh; Wang, Qi; Grecos, Christos

2012-06-01

Recently, the concept of Mobile Cloud Computing (MCC) has been proposed to offload the resource requirements in computational capabilities, storage and security from mobile devices into the cloud. Internet video applications such as real-time streaming are expected to be ubiquitously deployed and supported over the cloud for mobile users, who typically encounter a range of wireless networks of diverse radio access technologies during their roaming. However, real-time video streaming for mobile cloud users across heterogeneous wireless networks presents multiple challenges. The network-layer quality of service (QoS) provision to support high-quality mobile video delivery in this demanding scenario remains an open research question, and this in turn affects the application-level visual quality and impedes mobile users' perceived quality of experience (QoE). In this paper, we devise a framework to support real-time video streaming in this new mobile video networking paradigm and evaluate the performance of the proposed framework empirically through a lab-based yet realistic testing platform. One particular issue we focus on is the effect of users' mobility on the QoS of video streaming over the cloud. We design and implement a hybrid platform comprising of a test-bed and an emulator, on which our concept of mobile cloud computing, video streaming and heterogeneous wireless networks are implemented and integrated to allow the testing of our framework. As representative heterogeneous wireless networks, the popular WLAN (Wi-Fi) and MAN (WiMAX) networks are incorporated in order to evaluate effects of handovers between these different radio access technologies. The H.264/AVC (Advanced Video Coding) standard is employed for real-time video streaming from a server to mobile users (client nodes) in the networks. Mobility support is introduced to enable continuous streaming experience for a mobile user across the heterogeneous wireless network. Real-time video stream packets are captured for analytical purposes on the mobile user node. Experimental results are obtained and analysed. Future work is identified towards further improvement of the current design and implementation. With this new mobile video networking concept and paradigm implemented and evaluated, results and observations obtained from this study would form the basis of a more in-depth, comprehensive understanding of various challenges and opportunities in supporting high-quality real-time video streaming in mobile cloud over heterogeneous wireless networks.

Assessment and validation of managed lanes weaving and access guidelines.

DOT National Transportation Integrated Search

2010-06-01

The goal of this project was to establish spacing requirements for access points to managed lanes : with respect to the location of entrance and exit ramps on the general purpose lanes of the freeway. Traffic : entering the freeway destined for the m...

Testing new technology to restrict wildlife access to highways : phase 1.

DOT National Transportation Integrated Search

2016-06-01

Wildlife mitigation systems are as good as the weakest link. Often this is the wildlife exclusion barriers at vehicle access points in wildlife exclusion fencing (8 feet, 2.4 m high). The objective of this research was to find new technology solution...

Testing new technology to restrict wildlife access to highways : phase 2.

DOT National Transportation Integrated Search

2016-06-01

In wildlife mitigation systems, the weakest link is often the wildlife exclusion barriers at vehicle access points in wildlife exclusion fence (8 feet, 2.4 m high). The objective of this research was to evaluate the ability of electric pavement insta...

Information Retrieval Systems Retrieved? An Alternative to Present Dial Access Systems

ERIC Educational Resources Information Center

Hofmann, Norbert

1976-01-01

The expense of a dial access information retrieval system (DIARS) is weighed against its benefits. Problems of usage and efficacy for the student are outlined. A fully automated system is proposed instead, and its cost-saving features are pointed out. (MS)

Health information needs of professional nurses required at the point of care.

PubMed

Ricks, Esmeralda; ten Ham, Wilma

2015-06-11

Professional nurses work in dynamic environments and need to keep up to date with relevant information for practice in nursing to render quality patient care. Keeping up to date with current information is often challenging because of heavy workload, diverse information needs and the accessibility of the required information at the point of care. The aim of the study was to explore and describe the information needs of professional nurses at the point of care in order to make recommendations to stakeholders to develop a mobile library accessible by means of smart phones when needed. The researcher utilised a quantitative, descriptive survey design to conduct this study. The target population comprised 757 professional nurses employed at a state hospital. Simple random sampling was used to select a sample of the wards, units and departments for inclusion in the study. A convenience sample of 250 participants was selected. Two hundred and fifty structured self-administered questionnaires were distributed amongst the participants. Descriptive statistics were used to analyse the data. A total of 136 completed questionnaires were returned. The findings highlighted the types and accessible sources of information. Information needs of professional nurses were identified such as: extremely drug-resistant tuberculosis, multi-drug-resistant tuberculosis, HIV, antiretrovirals and all chronic lifestyle diseases. This study has enabled the researcher to identify the information needs required by professional nurses at the point of care to enhance the delivery of patient care. The research results were used to develop a mobile library that could be accessed by professional nurses.

Skull registration for prone patient position using tracked ultrasound

NASA Astrophysics Data System (ADS)

Underwood, Grace; Ungi, Tamas; Baum, Zachary; Lasso, Andras; Kronreif, Gernot; Fichtinger, Gabor

2017-03-01

PURPOSE: Tracked navigation has become prevalent in neurosurgery. Problems with registration of a patient and a preoperative image arise when the patient is in a prone position. Surfaces accessible to optical tracking on the back of the head are unreliable for registration. We investigated the accuracy of surface-based registration using points accessible through tracked ultrasound. Using ultrasound allows access to bone surfaces that are not available through optical tracking. Tracked ultrasound could eliminate the need to work (i) under the table for registration and (ii) adjust the tracker between surgery and registration. In addition, tracked ultrasound could provide a non-invasive method in comparison to an alternative method of registration involving screw implantation. METHODS: A phantom study was performed to test the feasibility of tracked ultrasound for registration. An initial registration was performed to partially align the pre-operative computer tomography data and skull phantom. The initial registration was performed by an anatomical landmark registration. Surface points accessible by tracked ultrasound were collected and used to perform an Iterative Closest Point Algorithm. RESULTS: When the surface registration was compared to a ground truth landmark registration, the average TRE was found to be 1.6+/-0.1mm and the average distance of points off the skull surface was 0.6+/-0.1mm. CONCLUSION: The use of tracked ultrasound is feasible for registration of patients in prone position and eliminates the need to perform registration under the table. The translational component of error found was minimal. Therefore, the amount of TRE in registration is due to a rotational component of error.

Assessment of exposure to electromagnetic fields from wireless computer networks (wi-fi) in schools; results of laboratory measurements.

PubMed

Peyman, A; Khalid, M; Calderon, C; Addison, D; Mee, T; Maslanyj, M; Mann, S

2011-06-01

Laboratory measurements have been carried out with examples of Wi-Fi devices used in UK schools to evaluate the radiofrequency power densities around them and the total emitted powers. Unlike previous studies, a 20 MHz bandwidth signal analyzer was used, enabling the whole Wi-Fi signal to be captured and monitored. The radiation patterns of the laptops had certain similarities, including a minimum toward the torso of the user and two maxima symmetrically opposed across a vertical plane bisecting the screen and keyboard. The maxima would have resulted from separate antennas mounted behind the top left and right corners of the laptop screens. The patterns for access points were more symmetrical with generally higher power densities at a given distance. The spherically-integrated radiated power (IRP) ranged from 5 to 17 mW for 15 laptops in the 2.45 GHz band and from 1 to 16 mW for eight laptops in the 5 GHz band. For practical reasons and because access points are generally wall-mounted with beams directed into the rooms, their powers were integrated over a hemisphere. These ranged from 3 to 28 mW for 12 access points at 2.4 GHz and from 3 to 29 mW for six access points at 5 GHz. In addition to the spherical measurements of IRP, power densities were measured at distances of 0.5 m and greater from the devices, and consistent with the low radiated powers, these were all much lower than the ICNIRP reference level.

A Point to Share: Streamlining Access Services Workflow through Online Collaboration, Communication, and Storage with Microsoft SharePoint

ERIC Educational Resources Information Center

Diffin, Jennifer; Chirombo, Fanuel; Nangle, Dennis; de Jong, Mark

2010-01-01

This article explains how the document management team (circulation and interlibrary loan) at the University of Maryland University College implemented Microsoft's SharePoint product to create a central hub for online collaboration, communication, and storage. Enhancing the team's efficiency, organization, and cooperation was the primary goal.…

Extended access to methamphetamine self-administration up-regulates dopamine transporter levels 72 hours after withdrawal in rats.

PubMed

D'Arcy, Christina; Luevano, Joe E; Miranda-Arango, Manuel; Pipkin, Joseph A; Jackson, Jonathan A; Castañeda, Eddie; Gosselink, Kristin L; O'Dell, Laura E

2016-01-01

Previous studies have demonstrated that there are persistent changes in dopamine systems following withdrawal from methamphetamine (METH). This study examined changes in striatal dopamine transporter (DAT), tyrosine hydroxylase (TH) and dopamine receptor 2 (D2) 72 h after withdrawal from METH intravenous self- administration (IVSA). Rats were given limited (1h) or extended (6h) access to METH IVSA (0.05 mg/kg/0.1 ml infusion) for 22 days. Controls did not receive METH IVSA. The rats given extended access to IVSA displayed higher METH intake during the first hour of drug access compared to rats given limited access. Extended access to METH also produced a concomitant increase in striatal DAT levels relative to drug-naïve controls. There were no changes in TH or D2 levels across groups. Previous studies have reported a decrease in striatal DAT levels during protracted periods (>7 days) of withdrawal from METH IVSA. This study extends previous work by showing an increase in striatal DAT protein expression during an earlier time point of withdrawal from this drug. These results are an important step toward understanding the dynamic changes in dopamine systems that occur during different time points of withdrawal from METH IVSA. Copyright © 2015 Elsevier B.V. All rights reserved.

Association of State Access Standards With Accessibility to Specialists for Medicaid Managed Care Enrollees.

PubMed

Ndumele, Chima D; Cohen, Michael S; Cleary, Paul D

2017-10-01

Medicaid recipients have consistently reported less timely access to specialists than patients with other types of coverage. By 2018, state Medicaid agencies will be required by the Center for Medicare and Medicaid Services (CMS) to enact time and distance standards for managed care organizations to ensure an adequate supply of specialist physicians for enrollees; however, there have been no published studies of whether these policies have significant effects on access to specialty care. To compare ratings of access to specialists for adult Medicaid and commercial enrollees before and after the implementation of specialty access standards. We used Consumer Assessment of Healthcare Providers and Systems survey data to conduct a quasiexperimental difference-in-differences (DID) analysis of 20 163 nonelderly adult Medicaid managed care (MMC) enrollees and 54 465 commercially insured enrollees in 5 states adopting access standards, and 37 290 MMC enrollees in 5 matched states that previously adopted access standards. Reported access to specialty care in the previous 6 months. Seven thousand six hundred ninety-eight (69%) Medicaid enrollees and 28 423 (75%) commercial enrollees reported that it was always or usually easy to get an appointment with a specialist before the policy implementation (or at baseline) compared with 11 889 (67%) of Medicaid enrollees in states that had previously implemented access standards. Overall, there was no significant improvement in timely access to specialty services for MMC enrollees in the period following implementation of standard(s) (adjusted difference-in-differences, -1.2 percentage points; 95% CI, -2.7 to 0.1), nor was there any impact of access standards on insurance-based disparities in access (0.6 percentage points; 95% CI, -4.3 to 5.4). There was heterogeneity across states, with 1 state that implemented both time and distance standards demonstrating significant improvements in access and reductions in disparities. Specialty access standards did not lead to widespread improvements in access to specialist physicians. Meaningful improvements in access to specialty care for Medicaid recipients may require additional interventions.

Antibiotic susceptibility profiling and virulence potential of Campylobacter jejuni isolates from different sources in Pakistan.

PubMed

Siddiqui, Fariha Masood; Akram, Muhammad; Noureen, Nighat; Noreen, Zobia; Bokhari, Habib

2015-03-01

To determine antibiotic resistance patterns and virulence potential of Campylobacter jejuni (C. jejuni) isolates from clinical human diarrheal infections, cattle and healthy broilers. Antibiotic sensitivity patterns of C. jejuni isolates were determined by Kirby Bauer Disc Diffusion assay. These isolates were then subjected to virulence profiling for the detection of mapA (membrane-associated protein), cadF (fibronectin binding protein), wlaN (beta-l,3-galactosyltransferase) and neuAB (sialic acid biosynthesis gene). Further C. jejuni isolates were grouped by random amplification of polymorphic DNA (RAPD) profiling. A total of 436 samples from poultry (n=88), cattle (n=216) and humans (n=132) from different locations were collected. Results revealed percentage of C. jejuni isolates were 35.2% (31/88), 25.0% (54/216) and 11.3% (15/132) among poultry, cattle and clinical human samples respectively. Antibiotic susceptibility results showed that similar resistance patterns to cephalothin was ie. 87.0%, 87.1% and 89%among humans, poultry and cattle respectively, followed by sulfamethoxazole+trimethoprim 40.0%, 38.7% and 31.0% in humans, poultry and cattle and Ampicillin 40%, 32% and 20% in humans, poultry and cattle respectively. Beta-lactamase activity was detected in 40.00% humans, 20.37% cattle and 32.25% in poultry C. jejuni isolates. CadF and mapA were present in all poultry, cattle and human C. jejuni isolates, wlaN was not detected in any isolate and neuAB was found in 9/31 (36%) poultry isolates. RAPD profiling results suggested high diversity of C. jejuni isolates. Detection of multidrug resistant C. jejuni strains from poultry and cattle is alarming as they can be potential hazard to humans. Moreover, predominant association of virulence factors, cadF and mapA (100% each) in C. jejuni isolates from all sources and neuAB (36%) with poultry isolates suggest the potential source of transmission of diverse types of C. jejuni to humans. Copyright © 2015 Hainan Medical College. Production and hosting by Elsevier B.V. All rights reserved.

Investing in Digital

ERIC Educational Resources Information Center

Grogg, Jill E.

2007-01-01

Librarians face two very pressing charges: make voluminous numbers of electronic resources as visible as possible in a landscape with multiple access points, and simultaneously manage all the technology, tasks, and data necessary to facilitate such ubiquitous access. In the past ten years, solutions have emerged and become commonplace in many…

When open access might not work: Understanding patient attitudes in appointment scheduling.

PubMed

Finkelstein, Stacey R; Liu, Nan; Rosenthal, David; Poghosyan, Lusine

2017-01-25

Open-access (OA) systems aim to reduce delays to care. However, recent evidence suggests that OA systems might reduce patient satisfaction and result in poorer patient experiences due to patients' inability to obtain appointments with their usual care provider. We conducted a series of experiments to explore the role of risk attitudes, an individual difference variable that measures preferences for risky options, in patients' perception of OA systems. The aim of the study was to investigate the relationship between patient's risk attitudes and attitudes toward OA systems and demonstrate whether patients' attitudes toward OA systems will vary as a function of their risk attitudes. Three separate experiments were conducted to assess the relationship between patient risk attitudes and their attitudes about OA systems. Study 1 (patient population) explored the aforementioned relationship. We explored two potential moderators for this effect: how salient the tradeoff is between delays to care and quality of care (Study 2; online population) and the severity of the patient's health condition (Study 3; patient population). Compared to risk-averse patients, risk-seeking patients have more favorable attitudes toward OA systems (a 1-point increase in risk attitudes on a 7-point scale resulted in a 0.44-point boost in attitudes toward OA systems on a 7-point scale). This relationship holds even when the tradeoff between access to care and quality of care is made salient (e.g., a practice informs patients they can have a same-day appointment but are unlikely to see their regular provider) and when people consider having a minor health condition. This relationship is attenuated when patients imagine having a serious medical condition because speedy access to care becomes a top priority. Risk-seeking patients have more favorable attitudes toward OA systems. Risk-seeking patients are primarily driven by speed to access at the potential expense of continuity of care. Organizations that better understand patient motives in scheduling medical appointments can introduce more effective interventions and positively impact patient experiences of care.

Proximity to Fast-Food Outlets and Supermarkets as Predictors of Fast-Food Dining Frequency.

PubMed

Athens, Jessica K; Duncan, Dustin T; Elbel, Brian

2016-08-01

This study used cross-sectional data to test the independent relationship of proximity to chain fast-food outlets and proximity to full-service supermarkets on the frequency of mealtime dining at fast-food outlets in two major urban areas, using three approaches to define access. Interactions between presence of a supermarket and presence of fast-food outlets as predictors of fast-food dining were also tested. Residential intersections for respondents in point-of-purchase and random-digit-dial telephone surveys of adults in Philadelphia, PA, and Baltimore, MD, were geocoded. The count of fast-food outlets and supermarkets within quarter-mile, half-mile, and 1-mile street network buffers around each respondent's intersection was calculated, as well as distance to the nearest fast-food outlet and supermarket. These variables were regressed on weekly fast-food dining frequency to determine whether proximity to fast food and supermarkets had independent and joint effects on fast-food dining. The effect of access to supermarkets and chain fast-food outlets varied by study population. Among telephone survey respondents, supermarket access was the only significant predictor of fast-food dining frequency. Point-of-purchase respondents were generally unaffected by proximity to either supermarkets or fast-food outlets. However, ≥1 fast-food outlet within a 1-mile buffer was an independent predictor of consuming more fast-food meals among point-of-purchase respondents. At the quarter-mile distance, ≥1 supermarket was predictive of fewer fast-food meals. Supermarket access was associated with less fast-food dining among telephone respondents, whereas access to fast-food outlets were associated with more fast-food visits among survey respondents identified at point-of-purchase. This study adds to the existing literature on geographic determinants of fast-food dining behavior among urban adults in the general population and those who regularly consume fast food. Copyright © 2016 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

Utilizing Fission Technology to Enable Rapid and Affordable Access to any Point in the Solar System

NASA Technical Reports Server (NTRS)

Houts, Mike; Bonometti, Joe; Morton, Jeff; Hrbud, Ivana; Bitteker, Leo; VanDyke, Melissa; Godfroy, T.; Pedersen, K.; Dobson, C.; Patton, B.;

Systems and methods for processing irradiation targets through a nuclear reactor

DOEpatents

Dayal, Yogeshwar; Saito, Earl F.; Berger, John F.; Brittingham, Martin W.; Morales, Stephen K.; Hare, Jeffrey M.

2016-05-03

Apparatuses and methods produce radioisotopes in instrumentation tubes of operating commercial nuclear reactors. Irradiation targets may be inserted and removed from instrumentation tubes during operation and converted to radioisotopes otherwise unavailable during operation of commercial nuclear reactors. Example apparatuses may continuously insert, remove, and store irradiation targets to be converted to useable radioisotopes or other desired materials at several different origin and termination points accessible outside an access barrier such as a containment building, drywell wall, or other access restriction preventing access to instrumentation tubes during operation of the nuclear plant.

Access and Quality of HIV-Related Point-of-Care Diagnostic Testing in Global Health Programs.

PubMed

Fonjungo, Peter N; Boeras, Debrah I; Zeh, Clement; Alexander, Heather; Parekh, Bharat S; Nkengasong, John N

2016-02-01

Access to point-of-care testing (POCT) improves patient care, especially in resource-limited settings where laboratory infrastructure is poor and the bulk of the population lives in rural settings. However, because of challenges in rolling out the technology and weak quality assurance measures, the promise of human immunodeficiency virus (HIV)-related POCT in resource-limited settings has not been fully exploited to improve patient care and impact public health. Because of these challenges, the Joint United Nations Programme on HIV/AIDS (UNAIDS), in partnership with other organizations, recently launched the Diagnostics Access Initiative. Expanding HIV programs, including the "test and treat" strategies and the newly established UNAIDS 90-90-90 targets, will require increased access to reliable and accurate POCT results. In this review, we examine various components that could improve access and uptake of quality-assured POC tests to ensure coverage and public health impact. These components include evaluation, policy, regulation, and innovative approaches to strengthen the quality of POCT. © The Author 2015. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

Combining survey and administrative data using state space models

Treesearch

Stephen Horn; Ray Czaplewski

2013-01-01

Even as access to transactional data has been transformed by harnessing electronic flows, use of satellite imagery, research access to linked customer level records, and harmonising collections across jurisdictions, official statisticians are under pressure to detect significant turning points within response times and resolutions that cannot be handled by present...

SUSTAINABILITY OF THE FILTR&OACUTE;N FOR MICROBIAL DISINFECTION

EPA Science Inventory

A significant portion, ~20%, of the world's population lives without access to safe water. Point of use (POU) devices for disinfection have been under-utilized as a tool to provide access to safe water. One such effective POU for producing potable water is the Filtr&oacut...

Current Approaches to Assessment in Self-Access Language Learning

ERIC Educational Resources Information Center

Reinders, Hayo; Lázaro, Noemí

2007-01-01

Assessment is generally seen as one of the key challenges in the field of self-access learning (Gardner & Miller, 1999; Champagne et al., 2001; Lai, 2001; Kinoshita Thomson, 1996). Many researchers and practitioners point to difficulties with assessing language gains in an environment in which variables cannot comprehensively be controlled…

An Evaluation of Online Help for the NOTIS OPAC.

ERIC Educational Resources Information Center

White, Frank

1994-01-01

Discussion of online help systems in online public access catalogs (OPACs) focuses on a study that evaluated the online help system for the NOTIS (Northwestern Online Total Integrated System) OPAC. Features of the system reviewed include online functions; training features; general interface features; access points; and message content and display…

Web OPAC Interfaces: An Overview.

ERIC Educational Resources Information Center

Babu, B. Ramesh; O'Brien, Ann

2000-01-01

Discussion of Web-based online public access catalogs (OPACs) focuses on a review of six Web OPAC interfaces in use in academic libraries in the United Kingdom. Presents a checklist and guidelines of important features and functions that are currently available, including search strategies, access points, display, links, and layout. (Author/LRW)

Taming the Wireless Frontier: PDAs, Tablets, and Laptops at Home on the Range.

ERIC Educational Resources Information Center

Williams, Joe

2003-01-01

Explains how Texas A&M University libraries developed a wireless network, including problems encountered, and describes three wireless services currently being delivered using Personal Digital Assistants (PDAs), tablet PCs, and wireless laptop computers. Topics include costs versus value; data security and access; wireless access points;…

A Didactical Framework for Studying Students' and Teachers' Activities when Learning and Teaching Mathematics

ERIC Educational Resources Information Center

Robert, Aline

2012-01-01

This paper draws an Activity Theoretical frame specific to mathematics at school with reference to both Vygotskian and Piagetian approaches. At a local point of view, the frame is oriented toward analysis of students' mathematical activities in the classroom. This local point of view is extended to a global point of view, to gain access to what…

Does lack of resources impair access to breast and cervical cancer screening in Japan?

PubMed

Sano, Hiroshi; Goto, Rei; Hamashima, Chisato

2017-01-01

To assess the impact of the quantity of resources for breast and cervical cancer screening on the participation rates in screening in clinical settings in municipalities, as well as to clarify whether lack of resources impairs access to cancer screening in Japan. Of the 1,746 municipalities in 2010, 1,443 (82.6%) and 1,469 (84.1%) were included in the analyses for breast and cervical cancer screening, respectively. In order to estimate the effects of the number of mammography units and of gynecologists on the participation rates in breast and cervical cancer screening in clinical settings, multiple regression analyses were performed using the interaction term for urban municipalities. The average participation rate in screening in clinical settings was 6.01% for breast cancer, and was 8.93% for cervical cancer. The marginal effect of the number of mammography units per 1,000 women was significantly positive in urban municipalities (8.20 percent point). The marginal effect of the number of gynecologists per 1,000 women was significantly positive in all municipalities (2.54 percent point) and rural municipalities (3.68 percent point). Lack of mammography units in urban areas and of gynecologists particularly in rural areas impaired access to breast and cervical cancer screening. Strategies are required that quickly improve access for the residents and increase their participation rates in cancer screening.

Does lack of resources impair access to breast and cervical cancer screening in Japan?

PubMed Central

Goto, Rei; Hamashima, Chisato

2017-01-01

Objectives To assess the impact of the quantity of resources for breast and cervical cancer screening on the participation rates in screening in clinical settings in municipalities, as well as to clarify whether lack of resources impairs access to cancer screening in Japan. Methods Of the 1,746 municipalities in 2010, 1,443 (82.6%) and 1,469 (84.1%) were included in the analyses for breast and cervical cancer screening, respectively. In order to estimate the effects of the number of mammography units and of gynecologists on the participation rates in breast and cervical cancer screening in clinical settings, multiple regression analyses were performed using the interaction term for urban municipalities. Results The average participation rate in screening in clinical settings was 6.01% for breast cancer, and was 8.93% for cervical cancer. The marginal effect of the number of mammography units per 1,000 women was significantly positive in urban municipalities (8.20 percent point). The marginal effect of the number of gynecologists per 1,000 women was significantly positive in all municipalities (2.54 percent point) and rural municipalities (3.68 percent point). Conclusions Lack of mammography units in urban areas and of gynecologists particularly in rural areas impaired access to breast and cervical cancer screening. Strategies are required that quickly improve access for the residents and increase their participation rates in cancer screening. PMID:28704430

An Optimal Delivery Format for Presentations Targeting Older Adults.

ERIC Educational Resources Information Center

Austin-Wells, Vonnette; Zimmerman, Teena; McDougall, Graham J., Jr.

2003-01-01

African-American, Hispanic, and white older adults (n=34) attended three information sessions presented via flipcharts, transparencies, and PowerPoint (one format per session). In focus groups, participants rated accessibility, novelty, and efficiency. They overwhelmingly preferred PowerPoint on all dimensions. (SK)

The Julia sets of basic uniCremer polynomials of arbitrary degree

NASA Astrophysics Data System (ADS)

Blokh, Alexander; Oversteegen, Lex

Let P be a polynomial of degree d with a Cremer point p and no repelling or parabolic periodic bi-accessible points. We show that there are two types of such Julia sets J_P . The red dwarf J_P are nowhere connected im kleinen and such that the intersection of all impressions of external angles is a continuum containing p and the orbits of all critical images. The solar J_P are such that every angle with dense orbit has a degenerate impression disjoint from other impressions and J_P is connected im kleinen at its landing point. We study bi-accessible points and locally connected models of J_P and show that such sets J_P appear through polynomial-like maps for generic polynomials with Cremer points. Since known tools break down for d>2 (if d>2 , it is not known if there are small cycles near p , while if d=2 , this result is due to Yoccoz), we introduce wandering ray continua in J_P and provide a new application of Thurston laminations.

Full impact of laboratory information system requires direct use by clinical staff: cluster randomized controlled trial.

PubMed

Blaya, Joaquín A; Shin, Sonya; Contreras, Carmen; Yale, Gloria; Suarez, Carmen; Asencios, Luis; Kim, Jihoon; Rodriguez, Pablo; Cegielski, Peter; Fraser, Hamish S F

2011-01-01

To evaluate the time to communicate laboratory results to health centers (HCs) between the e-Chasqui web-based information system and the pre-existing paper-based system. Cluster randomized controlled trial in 78 HCs in Peru. In the intervention group, 12 HCs had web access to results via e-Chasqui (point-of-care HCs) and forwarded results to 17 peripheral HCs. In the control group, 22 point-of-care HCs received paper results directly and forwarded them to 27 peripheral HCs. Baseline data were collected for 15 months. Post-randomization data were collected for at least 2 years. Comparisons were made between intervention and control groups, stratified by point-of-care versus peripheral HCs. For point-of-care HCs, the intervention group took less time to receive drug susceptibility tests (DSTs) (median 9 vs 16 days, p<0.001) and culture results (4 vs 8 days, p<0.001) and had a lower proportion of 'late' DSTs taking >60 days to arrive (p<0.001) than the control. For peripheral HCs, the intervention group had similar communication times for DST (median 22 vs 19 days, p=0.30) and culture (10 vs 9 days, p=0.10) results, as well as proportion of 'late' DSTs (p=0.57) compared with the control. Only point-of-care HCs with direct access to the e-Chasqui information system had reduced communication times and fewer results with delays of >2 months. Peripheral HCs had no benefits from the system. This suggests that health establishments should have point-of-care access to reap the benefits of electronic laboratory reporting.

Full impact of laboratory information system requires direct use by clinical staff: cluster randomized controlled trial

PubMed Central

Shin, Sonya; Contreras, Carmen; Yale, Gloria; Suarez, Carmen; Asencios, Luis; Kim, Jihoon; Rodriguez, Pablo; Cegielski, Peter; Fraser, Hamish S F

2010-01-01

Objective To evaluate the time to communicate laboratory results to health centers (HCs) between the e-Chasqui web-based information system and the pre-existing paper-based system. Methods Cluster randomized controlled trial in 78 HCs in Peru. In the intervention group, 12 HCs had web access to results via e-Chasqui (point-of-care HCs) and forwarded results to 17 peripheral HCs. In the control group, 22 point-of-care HCs received paper results directly and forwarded them to 27 peripheral HCs. Baseline data were collected for 15 months. Post-randomization data were collected for at least 2 years. Comparisons were made between intervention and control groups, stratified by point-of-care versus peripheral HCs. Results For point-of-care HCs, the intervention group took less time to receive drug susceptibility tests (DSTs) (median 9 vs 16 days, p<0.001) and culture results (4 vs 8 days, p<0.001) and had a lower proportion of ‘late’ DSTs taking >60 days to arrive (p<0.001) than the control. For peripheral HCs, the intervention group had similar communication times for DST (median 22 vs 19 days, p=0.30) and culture (10 vs 9 days, p=0.10) results, as well as proportion of ‘late’ DSTs (p=0.57) compared with the control. Conclusions Only point-of-care HCs with direct access to the e-Chasqui information system had reduced communication times and fewer results with delays of >2 months. Peripheral HCs had no benefits from the system. This suggests that health establishments should have point-of-care access to reap the benefits of electronic laboratory reporting. PMID:21113076

Access to Liver Transplantation in Different ABO-Blood Groups and "Exceptions Points" in a Model for End-Stage Liver Disease Allocation System: A Brazilian Single-Center Study.

PubMed

Martino, R B; Waisberg, D R; Dias, A P M; Inoue, V B S; Arantes, R M; Haddad, L B P; Rocha-Santos, V; Pinheiro, R S N; Nacif, L S; D'Albuquerque, L A C

2018-04-01

In the Model for End-Stage Liver Disease (MELD) system, patients with "MELD exceptions" points may have unfair privilege in the competition for liver grafts. Furthermore, organ distribution following identical ABO blood types may also result in unjust organ allocation. The aim of this study was to investigate access to liver transplantation in a tertiary Brazilian center, regarding "MELD exceptions" situations and among ABO-blood groups. A total of 465 adult patients on the liver waitlist from August 2015 to August 2016 were followed up until August 2017. Patients were divided into groups according to ABO-blood type and presence of "exceptions points." No differences in outcomes were observed among ABO-blood groups. However, patients from B and AB blood types spent less time on the list than patients from A and O groups (median, 46, 176, 415, and 401 days, respectively; P = .03). "Exceptions points" were granted for 141 patients (30.1%), hepatocellular carcinoma being the most common reason (52.4%). Patients with "exceptions points" showed higher transplantation rate, lower mortality on the list, and lower delta-MELD than non-exceptions patients (56.7% vs 19.1% [P < .01]; 18.4% vs 38.5% [P < .01], and 2.0 ± 2.6 vs 6.9 ± 7.0 [P < .01], respectively). Patients with refractory ascites had a higher mortality rate than those with other "exceptions" or without (48%). The MELD system provides equal access to liver transplantation among ABO-blood types, despite shorter time on the waitlist for AB and B groups. The current MELD exception system provides advantages for candidates with "exception points," resulting in superior outcomes compared with those without exceptions. Copyright © 2018 Elsevier Inc. All rights reserved.

Robotic percutaneous access to the kidney: comparison with standard manual access.

PubMed

Su, Li-Ming; Stoianovici, Dan; Jarrett, Thomas W; Patriciu, Alexandru; Roberts, William W; Cadeddu, Jeffrey A; Ramakumar, Sanjay; Solomon, Stephen B; Kavoussi, Louis R

2002-09-01

To evaluate the efficiency, accuracy, and safety of robotic percutaneous access to the kidney (PAKY) for percutaneous nephrolithotomy in comparison with conventional manual techniques. We compared the intraoperative access variables (number of access attempts, time to successful access, estimated blood loss, complications) of 23 patients who underwent robotic PAKY with the remote center of motion device (PAKY-RCM) with the same data from a contemporaneous series of 23 patients who underwent conventional manual percutaneous access to the kidney. The PAKY-RCM incorporates a robotic arm and a friction transmission with axial loading system to accurately position and insert a standard 18-gauge needle percutaneously into the kidney. The blood loss during percutaneous access was estimated on a four-point scale (1 = minimal to 4 = large). The color of effluent urine was graded on a four-point scale (1 = clear to 4 = red). The mean target calix width was 13.5 +/- 9.2 mm in the robotic group and 12.2 +/- 4.5 mm in the manual group (P = 0.57). When comparing PAKY-RCM with standard manual techniques, the mean number of attempts was 2.2 +/- 1.6 v 3.2 +/- 2.5 (P = 0.14), time to access was 10.4 +/- 6.5 minutes v 15.1 +/- 8.8 minutes (P = 0.06), estimated blood loss score was 1.3 +/- 0.49 v 1.7 +/- 0.66 (P = 0.14), and color of effluent urine following access was 2.0 +/- 0.90 v 2.1 +/- 0.7 (P = 0.82). The PAKY-RCM was successful in obtaining access in 87% (20 of 23) of cases. The other three patients (13%) required conversion to manual techniques. There were no major intraoperative complications in either group. Robotic PAKY is a feasible, safe, and efficacious method of obtaining renal access for nephrolithotomy. The number of attempts and time to access were comparable to those of standard manual percutaneous access techniques. These findings provide the groundwork for the development of a completely automated robot-assisted percutaneous renal access device.

Genetic divergence among Psidium accessions based on single nucleotide polymorphisms developed for Eucalyptus.

PubMed

Costa, S R; Santos, C A F

2017-05-04

The goal of this study was to analyze the genetic divergence among Psidium species accessions based on SNPs developed for Eucalyptus. Fifty-three Psidium accessions, including 47 P. guajava, were genotyped with EUCHIP60K. The dendrogram similarity ranged from 0.58 to 1.00, with a cophenetic value of 0.97. Five groups were identified at dendrogram cut point of 0.7: the first with 44 guava accessions, the second with 1 guava accession, the third with 3 P. guineense accessions, the forth with 2 guava accessions, and the fifth with 3 P. cattleianum accessions. The Bayesian analyses suggested seven subpopulations, with formation of two additional groups with guava accessions. Primers designed with Eucalyptus SNP sequences resulted in reliable Psidium amplicons on 6% polyacrylamide gels. In general, the SNP dendrogram agreed with biological genus structure, since different species were not grouped, indicating that transferability among Myrtaceae genus was possible and reliable.

Frequency Reconfigurable Quasi-Yagi Antenna with a Novel Balun Loading Four PIN Diodes

NASA Astrophysics Data System (ADS)

Xie, Peng; Wang, Guang-Ming; Li, Hai-Peng; Wen, Tong; Kong, Xiangxin

2018-04-01

A novel frequency reconfigurable Quasi-Yagi antenna is proposed. The antenna has two dipoles on different layers of the substrate and they are fed by two coplanar striplines. Four PIN diodes, loading inside the coplanar striplines, are used as the switches. By switching the states of the four diodes, the antenna can work in three modes with different working bands around 3.5 GHz (cover the band of WiMAX), 5.2 GHz (cover the band of WLAN) and 7 GHz respectively. In addition, the working bands can be independently tuned by adjusting several parameters of the antenna. A prototype antenna was fabricated and tested. Good agreement between the simulation and the measurement is achieved. The results prove that the antenna can realize frequency reconfiguration effectively while maintaining the pattern characteristic of Yagi antenna at all frequency.

Adaptive threshold control for auto-rate fallback algorithm in IEEE 802.11 multi-rate WLANs

NASA Astrophysics Data System (ADS)

Wu, Qilin; Lu, Yang; Zhu, Xiaolin; Ge, Fangzhen

2012-03-01

The IEEE 802.11 standard supports multiple rates for data transmission in the physical layer. Nowadays, to improve network performance, a rate adaptation scheme called auto-rate fallback (ARF) is widely adopted in practice. However, ARF scheme suffers performance degradation in multiple contending nodes environments. In this article, we propose a novel rate adaptation scheme called ARF with adaptive threshold control. In multiple contending nodes environment, the proposed scheme can effectively mitigate the frame collision effect on rate adaptation decision by adaptively adjusting rate-up and rate-down threshold according to the current collision level. Simulation results show that the proposed scheme can achieve significantly higher throughput than the other existing rate adaptation schemes. Furthermore, the simulation results also demonstrate that the proposed scheme can effectively respond to the varying channel condition.

Design and Analysis of a Triple Stop-band Filter Using Ratioed Periodical Defected Microstrip Structure

NASA Astrophysics Data System (ADS)

Jiang, Tao; Wang, Yanyan; Li, Yingsong

2017-07-01

In this paper, a triple stop-band filter with a ratioed periodical defected microstrip structure is proposed for wireless communication applications. The proposed ratioed periodical defected microstrip structures are spiral slots, which are embedded into a 50 Ω microstrip line to obtain multiple stop-bands. The performance of the proposed triple stop-band filter is investigated numerically and experimentally. Moreover, the equivalent circuit model of the proposed filter is also established and discussed. The results are given to verify that the proposed triple stop-band filter has three stop bands at 3.3 GHz, 5.2 GHz, 6.8 GHz to reject the unwanted signals, which is promising for integrating into UWB communication systems to efficiently prevent the potential interferences from unexpected narrowband signals such as WiMAX, WLAN and RFID communication systems.

Portable Wireless Device Threat Assessment for Aircraft Navigation Radios

NASA Technical Reports Server (NTRS)

Nguyen, Truong X.; Koppen, Sandra V.; Ely, Jay J.; Williams, Reuben A.; Smith, Laura J.; Salud, Maria Theresa P.

2004-01-01

This paper addresses the concern for Wireless Local Area Network devices and two-way radios to cause electromagnetic interference to aircraft navigation radio systems. Spurious radiated emissions from various IEEE 802.11a, 802.11b, and Bluetooth devices are characterized using reverberation chambers. The results are compared with baseline emissions from standard laptop computer and personal digital assistants (PDAs) that are currently allowed for use on aircraft. The results indicate that the WLAN devices tested are not more of a threat to aircraft navigation radios than standard laptop computers and PDAs in most aircraft bands. In addition, spurious radiated emission data from seven pairs of two-way radios are provided. These two-way radios emit at much higher levels in the bands considered. A description of the measurement process, device modes of operation and the measurement results are reported.

Beamforming transmission in IEEE 802.11ac under time-varying channels.

PubMed

Yu, Heejung; Kim, Taejoon

2014-01-01

The IEEE 802.11ac wireless local area network (WLAN) standard has adopted beamforming (BF) schemes to improve spectral efficiency and throughput with multiple antennas. To design the transmit beam, a channel sounding process to feedback channel state information (CSI) is required. Due to sounding overhead, throughput increases with the amount of transmit data under static channels. Under practical channel conditions with mobility, however, the mismatch between the transmit beam and the channel at transmission time causes performance loss when transmission duration after channel sounding is too long. When the fading rate, payload size, and operating signal-to-noise ratio are given, the optimal transmission duration (i.e., packet length) can be determined to maximize throughput. The relationship between packet length and throughput is also investigated for single-user and multiuser BF modes.

Beamforming Transmission in IEEE 802.11ac under Time-Varying Channels

PubMed Central

2014-01-01

The IEEE 802.11ac wireless local area network (WLAN) standard has adopted beamforming (BF) schemes to improve spectral efficiency and throughput with multiple antennas. To design the transmit beam, a channel sounding process to feedback channel state information (CSI) is required. Due to sounding overhead, throughput increases with the amount of transmit data under static channels. Under practical channel conditions with mobility, however, the mismatch between the transmit beam and the channel at transmission time causes performance loss when transmission duration after channel sounding is too long. When the fading rate, payload size, and operating signal-to-noise ratio are given, the optimal transmission duration (i.e., packet length) can be determined to maximize throughput. The relationship between packet length and throughput is also investigated for single-user and multiuser BF modes. PMID:25152927

Compact Dual-Band Bandpass Filter Using Stubs Loaded Ring Resonator

NASA Astrophysics Data System (ADS)

Xu, Jin

2016-01-01

This paper presents a novel second-order dual-band bandpass filter (BPF) by using proposed stubs loaded ring resonator. The resonant behavior of proposed stubs loaded ring resonator is analyzed by even-/odd-mode method, which shows its multiple-mode resonant characteristic. Parameters sweep is done so as to give the design guidelines. As an example, a second-order dual-band BPF operating at 1.8/5.2 GHz for GSM and WLAN applications is designed, fabricated and measured. The fabricated filter has a very compact size of 0.05λg×0.15λg. Measured results also show that the proposed dual-band BPF has a better than 20 dB rejection upper stopband from 5.47 GHz to 12.56 GHz. Good agreement is shown between the simulated and measured results.

Design of Compact Flower Shape Dual Notched-Band Monopole Antenna for Extended UWB Wireless Applications

NASA Astrophysics Data System (ADS)

Sharma, Manish; Awasthi, Y. K.; Singh, Himanshu; Kumar, Raj; Kumari, Sarita

2016-11-01

In this letter, a compact monopole antenna for ultra wideband (UWB) applications is proposed with small size of 18×20=360 mm2. Antenna consist of a flower shape radiating patch with a pair of C-shaped slots which offer two notch bands for WiMAX (3.04-3.68 GHz) & WLAN (4.73-5.76 GHz) and two rectangular shaped slots in the ground plane which provides a wide measured usable fractional extended bandwidth of 163 % (2.83-14.0 GHz) with improved VSWR. Moreover, it is also convenient for other wireless application as close range radar, 8-12 GHz in X-band. Measured radiation patterns exhibits nearly omnidirectional in H-plane and dipole like pattern in E-plane across the bandwidth and furthermore exhibits good time domain performance.

Fractal Based Triple Band High Gain Monopole Antenna

NASA Astrophysics Data System (ADS)

Pandey, Shashi Kant; Pandey, Ganga Prasad; Sarun, P. M.

2017-10-01

A novel triple-band microstrip fed planar monopole antenna is proposed and investigated. A fractal antenna is created by iterating a narrow pulse (NP) generator model at upper side of modified ground plane, which has a rhombic patch, for enhancing the bandwidth and gain. Three iterations are carried out to study the effects of fractal geometry on the antenna performance. The proposed antenna can operate over three frequency ranges viz, 3.34-4.8 GHz, 5.5-10.6 GHz and 13-14.96 GHz suitable for WLAN 5.2/5.8 GHz, WiMAX 3.5/5.5 GHz and X band applications respectively. Simulated and measured results are in good agreements with each others. Results show that antenna provides wide/ultra wide bandwidths, monopole like radiation patterns and very high antenna gains over the operating frequency bands.

Randomized comparison of operator radiation exposure comparing transradial and transfemoral approach for percutaneous coronary procedures: rationale and design of the minimizing adverse haemorrhagic events by TRansradial access site and systemic implementation of angioX - RAdiation Dose study (RAD-MATRIX).

PubMed

Sciahbasi, Alessandro; Calabrò, Paolo; Sarandrea, Alessandro; Rigattieri, Stefano; Tomassini, Francesco; Sardella, Gennaro; Zavalloni, Dennis; Cortese, Bernardo; Limbruno, Ugo; Tebaldi, Matteo; Gagnor, Andrea; Rubartelli, Paolo; Zingarelli, Antonio; Valgimigli, Marco

2014-06-01

Radiation absorbed by interventional cardiologists is a frequently under-evaluated important issue. Aim is to compare radiation dose absorbed by interventional cardiologists during percutaneous coronary procedures for acute coronary syndromes comparing transradial and transfemoral access. The randomized multicentre MATRIX (Minimizing Adverse Haemorrhagic Events by TRansradial Access Site and Systemic Implementation of angioX) trial has been designed to compare the clinical outcome of patients with acute coronary syndromes treated invasively according to the access site (transfemoral vs. transradial) and to the anticoagulant therapy (bivalirudin vs. heparin). Selected experienced interventional cardiologists involved in this study have been equipped with dedicated thermoluminescent dosimeters to evaluate the radiation dose absorbed during transfemoral or right transradial or left transradial access. For each access we evaluate the radiation dose absorbed at wrist, at thorax and at eye level. Consequently the operator is equipped with three sets (transfemoral, right transradial or left transradial access) of three different dosimeters (wrist, thorax and eye dosimeter). Primary end-point of the study is the procedural radiation dose absorbed by operators at thorax. An important secondary end-point is the procedural radiation dose absorbed by operators comparing the right or left radial approach. Patient randomization is performed according to the MATRIX protocol for the femoral or radial approach. A further randomization for the radial approach is performed to compare right and left transradial access. The RAD-MATRIX study will probably consent to clarify the radiation issue for interventional cardiologist comparing transradial and transfemoral access in the setting of acute coronary syndromes. Copyright © 2014 Elsevier Inc. All rights reserved.

Intraosseous access can be taught to medical students using the four-step approach.

PubMed

Afzali, Monika; Kvisselgaard, Ask Daffy; Lyngeraa, Tobias Stenbjerg; Viggers, Sandra

2017-03-02

The intraosseous (IO) access is an alternative route for vascular access when peripheral intravascular catheterization cannot be obtained. In Denmark the IO access is reported as infrequently trained and used. The aim of this pilot study was to investigate if medical students can obtain competencies in IO access when taught by a modified Walker and Peyton's four-step approach. Nineteen students attended a human cadaver course in emergency procedures. A lecture was followed by a workshop. Fifteen students were presented with a case where IO access was indicated and their performance was evaluated by an objective structured clinical examination (OSCE) and rated using a weighted checklist. To evaluate the validity of the checklist, three raters rated performance and Cohen's kappa was performed to assess inter-rater reliability (IRR). To examine the strength of the overall IRR, Randolph's free-marginal multi rater kappa was used. A maximum score of 15 points was obtained by nine (60%) of the participants and two participants (13%) scored 13 points with all three raters. Only one participant failed more than one item on the checklist. The expert rater rated lower with a mean score of 14.2 versus the non-expert raters with mean 14.6 and 14.3. The overall IRR calculated with Randolph's free-marginal multi rater kappa was 0.71. The essentials of the IO access procedure can be taught to medical students using a modified version of the Walker and Peyton's four-step approach and the checklist used was found reliable.

33 CFR 137.65 - Visual inspections of the facility, the real property on which the facility is located, and...

Code of Federal Regulations, 2010 CFR

2010-07-01

... rights-of-way, or other vantage point (e.g., aerial photography), including a visual inspection of areas... the facility is located from the nearest accessible vantage point, such as the property line or public...

Internet Connections: Understanding Your Access Options.

ERIC Educational Resources Information Center

Notess, Greg R.

1994-01-01

Describes levels of Internet connectivity, physical connections, and connection speeds. Compares options for connecting to the Internet, including terminal accounts, dial-up terminal accounts, direct connections through a local area network, and direct connections using SLIP (Serial Line Internet Protocol) or PPP (Point-to-Point Protocol). (eight…

40 CFR 60.691 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... collection point for stormwater runoff received directly from refinery surfaces and for refinery wastewater... chamber in a stationary manner and which does not move with fluctuations in wastewater levels. Floating... separator. Junction box means a manhole or access point to a wastewater sewer system line. No detectable...

Linking Advanced Visualization and MATLAB for the Analysis of 3D Gene Expression Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruebel, Oliver; Keranen, Soile V.E.; Biggin, Mark

Three-dimensional gene expression PointCloud data generated by the Berkeley Drosophila Transcription Network Project (BDTNP) provides quantitative information about the spatial and temporal expression of genes in early Drosophila embryos at cellular resolution. The BDTNP team visualizes and analyzes Point-Cloud data using the software application PointCloudXplore (PCX). To maximize the impact of novel, complex data sets, such as PointClouds, the data needs to be accessible to biologists and comprehensible to developers of analysis functions. We address this challenge by linking PCX and Matlab via a dedicated interface, thereby providing biologists seamless access to advanced data analysis functions and giving bioinformatics researchersmore » the opportunity to integrate their analysis directly into the visualization application. To demonstrate the usefulness of this approach, we computationally model parts of the expression pattern of the gene even skipped using a genetic algorithm implemented in Matlab and integrated into PCX via our Matlab interface.« less

A New Regulatory Policy for FTTx-Based Next-Generation Access Networks

NASA Astrophysics Data System (ADS)

Makarovič, Boštjan

2013-07-01

This article critically assesses the latest European Commission policies in relation to next-generation access investment that put focus on regulated prices and relaxing of wholesale access obligations. Pointing at the vital socio-legal and economic arguments, it further challenges the assumptions of the current EU regulatory framework and calls for a more contractual utility-based model of regulation instead of the current system that overly relies on market-driven infrastructure-based competition.

The use of online information resources by nurses.

PubMed

Wozar, Jody A; Worona, Paul C

2003-04-01

Based on the results of an informal needs assessment, the Usage of Online Information Resources by Nurses Project was designed to provide clinical nurses with accurate medical information at the point of care by introducing them to existing online library resources through instructional classes. Actual usage of the resources was then monitored for a set period of time. A two-hour hands-on class was developed for interested nurses. Participants were instructed in the content and use of several different online resources. A special Web page was designed for this project serving as an access point to the resources. Using a password system and WebTrends trade mark software, individual participant's usage of the resources was monitored for a thirty-day period following the class. At the end of the thirty days, usage results were tabulated, and participants were sent general evaluation forms. Eight participants accessed the project page thirty-nine times in a thirty-day period. The most accessed resource was Primary Care Online (PCO), accessed thirty-three times. PCO was followed by MD Consult (17), Ovid (8), NLM resources (5), and electronic journals (1). The individual with the highest usage accessed the project page thirteen times. Practicing clinical nurses will use online medical information resources if they are first introduced to them and taught how to access and use them. Health sciences librarians can play an important role in providing instruction to this often overlooked population.

Custom-made raster method for fistula and graft.

PubMed

Blokker, C

2005-01-01

Unfamiliarity with fistula and graft characteristics can lead to failed punctures, haematomas and sometimes access occlusion. The Custom-made Raster Method provides detailed shunt visualisation and angiographic images by using photo-editing software. Access veins of an individual shunt and an adapted raster are projected on a digital picture of the arm. During angiography the shunt arm is fixated and a digital picture is taken from a fixed vertical angle and distance. Reference points are marked on the shunt arm, which serves as a fixation to draw a raster with coordination points. In this way a picture is created similar to a roadmap with veins. There is complete integration of digital and radiological images by using software programmes Adobe Photoshop + Illustrator or Agfa Web 1000 under Windows XP. All illustrations fit 1:1 by scaling up or down without distortion. Editing with Photoshop gives a precise projection of shunt veins on the real coloured background of the digital photograph. In this projection the grey angiography background is made completely transparent. The system can contain more detailed information in combination with echo (duplex) images of depth and diameter. This visualisation method is a useful tool for multi disciplinary access meetings with intervention radiologists, access surgeons and nephrologists. Access malfunction, aneurysms and stenosis can be projected at the exact location. The system leads to clear and concrete puncture advice. Transfer of access information and communication to other dialysis centres is facilitated.

Competency-Based Education: What Is the Issue and Why Does It Matter? Policy Snapshot

ERIC Educational Resources Information Center

Anderson, Lexi

2017-01-01

The increasing need for highly-skilled employees in the workplace has policymakers and higher education leaders focused on innovative ways for students to access postsecondary education. These access points can include online programs, prior learning assessments and, the subject of this snapshot, competency-based education. The National Center for…

Drafted: I Want You to Deliver E-Government

ERIC Educational Resources Information Center

Bertot, John Carlo; Jaeger, Paul T.; Langa, Lesley A.; McClure, Charles R.

2006-01-01

Public access to the Internet and computers is transforming public libraries into de facto e-government access points, for such disparate services as disaster relief, Medicare drug plans, and even benefits for children and families. This new role for public libraries is not just user-initiated. Government agencies now refer people to public…

20 CFR 1010.300 - What processes are to be implemented to identify covered persons?

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false What processes are to be implemented to identify covered persons? 1010.300 Section 1010.300 Employees' Benefits OFFICE OF THE ASSISTANT SECRETARY... processes to identify covered persons who physically access service delivery points or who access virtual...

Multi-component access to a commercially available weight loss program: A randomized controlled trial

USDA-ARS?s Scientific Manuscript database

This study examined weight loss between a community-based, intensive behavioral counseling program (Weight Watchers PointsPlus that included three treatment access modes and a self-help condition. A total of 292 participants were randomized to a Weight Watchers (WW; n=147) or a self-help condition (...

78 FR 5505 - Turkey Point, Units 3 and 4; Application and Amendment to Facility Operating License Involving...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-25

...: You may access information and comment submissions related to this document, which the NRC possesses... access information related to this document, which the NRC possesses and are publicly available, by any... generation and the potential for stainless steel stress corrosion cracking is reduced. Therefore, the...

Access to Microsoft Windows 95 for Persons with Low Vision: An Overview.

ERIC Educational Resources Information Center

Shragai, Y.

1995-01-01

This article examines Windows 95, pointing out differences and improvements from Windows 3.1 for persons with low vision. Windows 95 is seen as providing substantially greater accessibility than Windows 3.1, though the graphical user interface may still pose serious problems for some users with low vision. (DB)

Multi-component access to a community-based weight loss program: 12 week results

USDA-ARS?s Scientific Manuscript database

The current study examined weight loss between a comprehensive lifestyle modification program (Weight Watchers PointsPlus program) that included three ways to access and a self-help (SH) condition. A total of 293 participants were randomized to either a Weight Watchers condition (WW) (n=148) or a SH...

9. Acircuit weather cover in foreground, personnel access hatch, transporter/erector ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. A-circuit weather cover in foreground, personnel access hatch, transporter/erector grounding points at right center - Ellsworth Air Force Base, Delta Flight, Launch Facility D-6, 4 miles north of Badlands National Park Headquarters, 4.5 miles east of Jackson County line on county road, Interior, Jackson County, SD

Wireless Computing Architecture III

DTIC Science & Technology

2013-09-01

MIMO Multiple-Input and Multiple-Output MIMO /CON MIMO with concurrent hannel access and estimation MU- MIMO Multiuser MIMO OFDM Orthogonal...compressive sensing \\; a design for concurrent channel estimation in scalable multiuser MIMO networking; and novel networking protocols based on machine...Network, Antenna Arrays, UAV networking, Angle of Arrival, Localization MIMO , Access Point, Channel State Information, Compressive Sensing 16

Examining Heterogeneity in the Effect of Taking Algebra in Eighth Grade

ERIC Educational Resources Information Center

Rickles, Jordan H.

2013-01-01

Increased access to algebra was a focal point of the National Mathematics Advisory Panel's 2008 report on improving mathematics learning in the United States. Past research found positive effects for early access to algebra, but the focus on average effects may mask important variation across student subgroups. The author addresses whether these…

Improving Student Attainment in Community Colleges: Institutional Characteristics and Policies

ERIC Educational Resources Information Center

Bailey, Thomas; Alfonso, Mariana; Calcagno, Juan Carlos; Jenkins, Davis; Kienzl, Gregory; Leinbach, Tim

2004-01-01

Community colleges are a crucial point of access to higher education for low-income, minority, and other underserved students. These groups are overrepresented (with respect to their share of undergraduate enrollment) in two year and less than two year post secondary institutions. The community college access mission is built on low tuition, …

Mental Health Referrals: A Survey of Practicing School Psychologists

ERIC Educational Resources Information Center

Villarreal, Victor

2018-01-01

Schools are the most common entry point for accessing mental health services for school-age children. Children may access school-based services as part of a multitiered system of supports or other service models, such as school-based health centers. However, limitations associated with school-based services (e.g., lack of time, inability to…

Where We Stand: Early Childhood Education.

ERIC Educational Resources Information Center

American Federation of Teachers, Washington, DC.

This document details the position of the American Federation of Teachers (AFT) regarding universal access to early childhood education as represented in a resolution of the AFT convention in 2003. The document points out that the lack of access to high-quality preschool programs is a major problem affecting nearly every working family, and as the…

Pan European Phenological database (PEP725): a single point of access for European data.

PubMed

Templ, Barbara; Koch, Elisabeth; Bolmgren, Kjell; Ungersböck, Markus; Paul, Anita; Scheifinger, Helfried; Rutishauser, This; Busto, Montserrat; Chmielewski, Frank-M; Hájková, Lenka; Hodzić, Sabina; Kaspar, Frank; Pietragalla, Barbara; Romero-Fresneda, Ramiro; Tolvanen, Anne; Vučetič, Višnja; Zimmermann, Kirsten; Zust, Ana

2018-06-01

The Pan European Phenology (PEP) project is a European infrastructure to promote and facilitate phenological research, education, and environmental monitoring. The main objective is to maintain and develop a Pan European Phenological database (PEP725) with an open, unrestricted data access for science and education. PEP725 is the successor of the database developed through the COST action 725 "Establishing a European phenological data platform for climatological applications" working as a single access point for European-wide plant phenological data. So far, 32 European meteorological services and project partners from across Europe have joined and supplied data collected by volunteers from 1868 to the present for the PEP725 database. Most of the partners actively provide data on a regular basis. The database presently holds almost 12 million records, about 46 growing stages and 265 plant species (including cultivars), and can be accessed via http://www.pep725.eu/ . Users of the PEP725 database have studied a diversity of topics ranging from climate change impact, plant physiological question, phenological modeling, and remote sensing of vegetation to ecosystem productivity.

Pan European Phenological database (PEP725): a single point of access for European data

NASA Astrophysics Data System (ADS)

Templ, Barbara; Koch, Elisabeth; Bolmgren, Kjell; Ungersböck, Markus; Paul, Anita; Scheifinger, Helfried; Rutishauser, This; Busto, Montserrat; Chmielewski, Frank-M.; Hájková, Lenka; Hodzić, Sabina; Kaspar, Frank; Pietragalla, Barbara; Romero-Fresneda, Ramiro; Tolvanen, Anne; Vučetič, Višnja; Zimmermann, Kirsten; Zust, Ana

2018-02-01

The Pan European Phenology (PEP) project is a European infrastructure to promote and facilitate phenological research, education, and environmental monitoring. The main objective is to maintain and develop a Pan European Phenological database (PEP725) with an open, unrestricted data access for science and education. PEP725 is the successor of the database developed through the COST action 725 "Establishing a European phenological data platform for climatological applications" working as a single access point for European-wide plant phenological data. So far, 32 European meteorological services and project partners from across Europe have joined and supplied data collected by volunteers from 1868 to the present for the PEP725 database. Most of the partners actively provide data on a regular basis. The database presently holds almost 12 million records, about 46 growing stages and 265 plant species (including cultivars), and can be accessed via http://www.pep725.eu/. Users of the PEP725 database have studied a diversity of topics ranging from climate change impact, plant physiological question, phenological modeling, and remote sensing of vegetation to ecosystem productivity.

Using speech recognition to enhance the Tongue Drive System functionality in computer access.

PubMed

Huo, Xueliang; Ghovanloo, Maysam

2011-01-01

Tongue Drive System (TDS) is a wireless tongue operated assistive technology (AT), which can enable people with severe physical disabilities to access computers and drive powered wheelchairs using their volitional tongue movements. TDS offers six discrete commands, simultaneously available to the users, for pointing and typing as a substitute for mouse and keyboard in computer access, respectively. To enhance the TDS performance in typing, we have added a microphone, an audio codec, and a wireless audio link to its readily available 3-axial magnetic sensor array, and combined it with a commercially available speech recognition software, the Dragon Naturally Speaking, which is regarded as one of the most efficient ways for text entry. Our preliminary evaluations indicate that the combined TDS and speech recognition technologies can provide end users with significantly higher performance than using each technology alone, particularly in completing tasks that require both pointing and text entry, such as web surfing.

76 FR 76713 - California Independent System Operator Corporation; Notice of Technical Conference

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-08

...) proposal to eliminate convergence bidding at intertie scheduling points. Take notice that such conference...'s proposal to eliminate convergence bidding at intertie scheduling points. A subsequent notice... Act of 1973. For accessibility accommodations please send an email to [email protected] or call...

Animals as Mobile Biological Sensors for Forest Fire Detection.

PubMed

Sahin, Yasar Guneri

2007-12-04

This paper proposes a mobile biological sensor system that can assist in earlydetection of forest fires one of the most dreaded natural disasters on the earth. The main ideapresented in this paper is to utilize animals with sensors as Mobile Biological Sensors(MBS). The devices used in this system are animals which are native animals living inforests, sensors (thermo and radiation sensors with GPS features) that measure thetemperature and transmit the location of the MBS, access points for wireless communicationand a central computer system which classifies of animal actions. The system offers twodifferent methods, firstly: access points continuously receive data about animals' locationusing GPS at certain time intervals and the gathered data is then classified and checked tosee if there is a sudden movement (panic) of the animal groups: this method is called animalbehavior classification (ABC). The second method can be defined as thermal detection(TD): the access points get the temperature values from the MBS devices and send the datato a central computer to check for instant changes in the temperatures. This system may beused for many purposes other than fire detection, namely animal tracking, poachingprevention and detecting instantaneous animal death.

Design and FPGA implementation for MAC layer of Ethernet PON

NASA Astrophysics Data System (ADS)

Zhu, Zengxi; Lin, Rujian; Chen, Jian; Ye, Jiajun; Chen, Xinqiao

2004-04-01

Ethernet passive optical network (EPON), which represents the convergence of low-cost, high-bandwidth and supporting multiple services, appears to be one of the best candidates for the next-generation access network. The work of standardizing EPON as a solution for access network is still underway in the IEEE802.3ah Ethernet in the first mile (EFM) task force. The final release is expected in 2004. Up to now, there has been no standard application specific integrated circuit (ASIC) chip available which fulfills the functions of media access control (MAC) layer of EPON. The MAC layer in EPON system has many functions, such as point-to-point emulation (P2PE), Ethernet MAC functionality, multi-point control protocol (MPCP), network operation, administration and maintenance (OAM) and link security. To implement those functions mentioned above, an embedded real-time operating system (RTOS) and a flexible programmable logic device (PLD) with an embedded processor are used. The software and hardware functions in MAC layer are realized through programming embedded microprocessor and field programmable gate array(FPGA). Finally, some experimental results are given in this paper. The method stated here can provide a valuable reference for developing EPON MAC layer ASIC.

Animals as Mobile Biological Sensors for Forest Fire Detection

PubMed Central

2007-01-01

This paper proposes a mobile biological sensor system that can assist in early detection of forest fires one of the most dreaded natural disasters on the earth. The main idea presented in this paper is to utilize animals with sensors as Mobile Biological Sensors (MBS). The devices used in this system are animals which are native animals living in forests, sensors (thermo and radiation sensors with GPS features) that measure the temperature and transmit the location of the MBS, access points for wireless communication and a central computer system which classifies of animal actions. The system offers two different methods, firstly: access points continuously receive data about animals' location using GPS at certain time intervals and the gathered data is then classified and checked to see if there is a sudden movement (panic) of the animal groups: this method is called animal behavior classification (ABC). The second method can be defined as thermal detection (TD): the access points get the temperature values from the MBS devices and send the data to a central computer to check for instant changes in the temperatures. This system may be used for many purposes other than fire detection, namely animal tracking, poaching prevention and detecting instantaneous animal death. PMID:28903281

Unbundling in Current Broadband and Next-Generation Ultra-Broadband Access Networks

NASA Astrophysics Data System (ADS)

Gaudino, Roberto; Giuliano, Romeo; Mazzenga, Franco; Valcarenghi, Luca; Vatalaro, Francesco

2014-05-01

This article overviews the methods that are currently under investigation for implementing multi-operator open-access/shared-access techniques in next-generation access ultra-broadband architectures, starting from the traditional "unbundling-of-the-local-loop" techniques implemented in legacy twisted-pair digital subscriber line access networks. A straightforward replication of these copper-based unbundling-of-the-local-loop techniques is usually not feasible on next-generation access networks, including fiber-to-the-home point-to-multipoint passive optical networks. To investigate this issue, the article first gives a concise description of traditional copper-based unbundling-of-the-local-loop solutions, then focalizes on both next-generation access hybrid fiber-copper digital subscriber line fiber-to-the-cabinet scenarios and on fiber to the home by accounting for the mix of regulatory and technological reasons driving the next-generation access migration path, focusing mostly on the European situation.

Leveraging Open Standards and Technologies to Enhance Community Access to Earth Science Lidar Data

NASA Astrophysics Data System (ADS)

Crosby, C. J.; Nandigam, V.; Krishnan, S.; Cowart, C.; Baru, C.; Arrowsmith, R.

2011-12-01

Lidar (Light Detection and Ranging) data, collected from space, airborne and terrestrial platforms, have emerged as an invaluable tool for a variety of Earth science applications ranging from ice sheet monitoring to modeling of earth surface processes. However, lidar present a unique suite of challenges from the perspective of building cyberinfrastructure systems that enable the scientific community to access these valuable research datasets. Lidar data are typically characterized by millions to billions of individual measurements of x,y,z position plus attributes; these "raw" data are also often accompanied by derived raster products and are frequently terabytes in size. As a relatively new and rapidly evolving data collection technology, relevant open data standards and software projects are immature compared to those for other remote sensing platforms. The NSF-funded OpenTopography Facility project has developed an online lidar data access and processing system that co-locates data with on-demand processing tools to enable users to access both raw point cloud data as well as custom derived products and visualizations. OpenTopography is built on a Service Oriented Architecture (SOA) in which applications and data resources are deployed as standards compliant (XML and SOAP) Web services with the open source Opal Toolkit. To develop the underlying applications for data access, filtering and conversion, and various processing tasks, OpenTopography has heavily leveraged existing open source software efforts for both lidar and raster data. Operating on the de facto LAS binary point cloud format (maintained by ASPRS), open source libLAS and LASlib libraries provide OpenTopography data ingestion, query and translation capabilities. Similarly, raster data manipulation is performed through a suite of services built on the Geospatial Data Abstraction Library (GDAL). OpenTopography has also developed our own algorithm for high-performance gridding of lidar point cloud data, Points2Grid, and have released the code as an open source project. An emerging conversation that the lidar community and OpenTopography are actively engaged in is the need for open, community supported standards and metadata for both full waveform and terrestrial (waveform and discrete return) lidar data. Further, given the immature nature of many lidar data archives and limited online access to public domain data, there is an opportunity to develop interoperable data catalogs based on an open standard such as the OGC CSW specification to facilitate discovery and access to Earth science oriented lidar data.

Increasing equity of access to point-of-use water treatment products through social marketing and entrepreneurship: a case study in western Kenya.

PubMed

Freeman, Matthew C; Quick, Robert E; Abbott, Daniel P; Ogutu, Paul; Rheingans, Richard

2009-09-01

Point-of-use water chlorination reduces diarrhoea risk by 25-85%. Social marketing has expanded access to inexpensive sodium hypochlorite for water treatment, at a cost of less than US$0.01 per day, in Kenya. To increase product access, women's groups in western Kenya were trained to educate neighbours and sell health products to generate income. We evaluated this programme's impact on equity of access to water treatment products in a cross-sectional survey. We surveyed 487 randomly selected households in eight communities served by the women's groups. Overall, 20% (range 5-39%) of households in eight communities purchased and used chlorine, as confirmed by residual chlorine observed in stored water. Multivariate models using illiteracy and the poorest socioeconomic status as a referent showed that persons with at least some primary education (OR 2.5, 95% CI 1.8, 3.5) or secondary education (OR 5.4, 95% CI 1.6, 17.5) and persons in the four wealthiest quintiles (OR 2.5, 95% CI 1.0, 6.0) were more likely to chlorinate stored water. While this implementation model was associated with good product penetration and use, barriers to access to inexpensive water treatment remained among the very poor and less educated.

76 FR 79676 - California Independent System Operator Corporation; Supplemental Notice of Agenda and Discussion...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-22

... Operator Corporation's (CAISO) proposal to eliminate convergence bidding at intertie scheduling points.\\1... proposal to eliminate convergence bidding at intertie scheduling points in detail. No formal presentations... 1973. For accessibility accommodations please send an email to [email protected] or call toll free...

77 FR 4989 - Turning Point Solar LLC: Notice of Availability of an Environmental Assessment

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-01

... constructing a 49.9 megawatt (MW) ground- mounted solar photovoltaic generating facility in Noble County, Ohio... monocrystalline photovoltaic panels mounted on fixed solar racking equipment and the construction of access roads... DEPARTMENT OF AGRICULTURE Rural Utilities Service Turning Point Solar LLC: Notice of Availability...

The Lagrange Points

ERIC Educational Resources Information Center

Lovell, M.S.

2007-01-01

This paper presents a derivation of all five Lagrange points by methods accessible to sixth-form students, and provides a further opportunity to match Newtonian gravity with centripetal force. The predictive powers of good scientific theories are also discussed with regard to the philosophy of science. Methods for calculating the positions of the…

Water Quality vs. Sanitation Accessibility: What is the most effective intervention point for preventing cholera in Dhaka, Bangladesh?

NASA Astrophysics Data System (ADS)

Majumder, M. S.; Gute, D.; Faruque, A. S.

2011-12-01

Every year, 3 to 5 million individuals contract cholera, an acute diarrheal infection that is caused by the ingestion of food or water containing the Vibrio cholerae bacterium. Because cholera is a waterborne disease, it can be transmitted quickly in environments with inadequate water and sanitation systems where infected waste can easily pollute drinking water. Today, Bangladesh continues to struggle with endemic cholera. Donor organizations address water and sanitation via localized initiatives, including the installation of community water collection sites (i.e. tubewells; water-boiling points; etc.). At this small-scale level, water quality and sanitation accessibility can be improved independently of one another, and when resources are limited, donors must invest in the most effective disease prevention options. This study used laboratory-confirmed cholera incidence data (2000-2009) collected by the International Centre of Diarrheal Disease Research, Bangladesh at their on-site hospital to compare the efficacy of interventions addressing water quality versus sanitation accessibility in Dhaka, Bangladesh. Data regarding use of sanitary latrines and boiling of drinking water were extracted from sequential patient interviews conducted at the Dhaka facility and used as surrogate variables for sanitation accessibility and water quality respectively. Our analysis indicates that boiling water is 10 times more effective at preventing cholera than the use of a sanitary latrine. This finding suggests that regulating water quality is perhaps more critical to cholera prevention than increasing sanitation accessibility in an urban environment like that of Dhaka. At present, WaterAid - one of Bangladesh's most significant water and sanitation donor organizations - invests the majority of its budget on improving sanitation accessibility. The World Health Organization and the United Nations Millennium Development Goals also prioritize sanitation accessibility. However, in Bangladesh, water quality must be given greater attention. As the nation's most prevalent diarrheal disease, cholera outbreaks result in incalculable lost wages and treatment expenses, taken from the pockets of an already impoverished society. Bangladesh cannot afford cholera; prevention is the only sustainable control option, and water quality is the most effective intervention point for Dhaka, Bangladesh.

Biological research on a Space Station

NASA Technical Reports Server (NTRS)

Krikorian, A. D.; Johnson, Catherine C.

1990-01-01

A Space Station can provide reliable, long duration access to ug environments for basic and applied biological research. The uniqueness of access to near-weightless environments to probe fundamental questions of significance to gravitational and Space biologists can be exploited from many vantage points. Access to centrifuge facilities that can provide 1 g and hypo-g controls will permit identification of gravity-dependent or primary effects. Understanding secondary effects of the ug environment as well will allow a fuller exploitation of the Space environment.

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

NASA Astrophysics Data System (ADS)

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.

Addressing Point of Need in Interactive Multimedia Instruction: A Conceptual Review and Evaluation

DTIC Science & Technology

2013-11-01

classroom setting, ability grouping refers to the practice of putting students into groups on the basis of individual group members’ ability levels...presentation of elaborated/basic vs. advanced material, color cuing, pretesting and modifying learning presentation based on performance) ...learners’ points of need. The point of need concept is focused both on the accessibility of information to support the learning process as well as

Topographic and location map of Bonita Point Coast Guard and ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Topographic and location map of Bonita Point Coast Guard and lighthouse station, June 1940, this drawing shows the Bonita Ridge access road retaining wall and general conditions at Fort Barry and Bonita Ridge (upper left) before the construction of Signal Corps Radar (S.C.R.) 296 Station 5 - Fort Barry, Signal Corps Radar 296, Station 5, Transmitter Building Foundation, Point Bonita, Marin Headlands, Sausalito, Marin County, CA

Understanding differences in access to water fountains and sugar-sweetened beverages in children׳s environments: a pilot study in high and low deprivation neighbourhoods.

PubMed

Pearson, Amber L; de Latour, Phillip; Kemp, Gabrielle; Findlay, Nohoana; Halim, Angela; Atkinson, Nicola; Chong, Mark; Cameron, Rose; Brown, Courtney; Kim, Grace; Campbell, Paul; Hills, Toby; Jayawant, Aditya; Chae, Matthew; Bhagavan, Chiranth; French, Claire; Jenkin, Gabrielle; Smith, Moira; Signal, Louise

2014-11-01

Access to water fountains and sugar-sweetened beverages (SSBs) in children׳s environments may impact on child obesity and may vary with neighbourhood deprivation. Our pilot analyses of access to water fountains and SSBs in Wellington, New Zealand revealed that water fountain access was high in school environments and low in recreational environments. There were also differences in water fountain and SSB access points by neighbourhood deprivation. The methods piloted in this study could be translated in a larger study, more capable of detecting significant differences in access and allowing for more sophisticated analyses. Such future studies may provide important evidence for the improvement of children׳s health and well-being. Copyright © 2014 Elsevier Ltd. All rights reserved.

Web based information on clinical toxicology for the United Kingdom: uptake and utilization of TOXBASE in 2000

PubMed Central

Nicholas Bateman, D; Good, Alison M; Kelly, Catherine A; Laing, William J

2002-01-01

Aims To examine the use and uptake of TOXBASE, an Internet database for point of care provision of poisons information in the United Kingdom during its first calendar year of web-based access. Methods Interrogation of the database software to examine: use by different types of user and geographical origin; profile of ingredient and product access; time of access to the system; profile of access to other parts of the database. Results Registered users of the system increased in the first full year of operation (1224 new users) and usage of the system increased to 111 410 sessions with 190 223 product monograph accesses in 2000. Major users were hospitals, in particular accident and emergency departments. NHS Direct, a public access information service staffed by nurses, also made increasing use of the system. Usage per head of population was highest in Northern Ireland and Scotland, and least in southern England. Ingredients accessed most frequently were similar in all four countries of the UK. Times of use of the system reflect clinical activity, with hospitals making many accesses during night-time hours. The most popular parts of the database other than poisons information were those dealing with childhood poisoning, information on decontamination procedures, teratology information and slang terms for drugs of abuse. Conclusions This Internet system has been widely used in its first full year of operation. The provision of clinically relevant, up to date, information at the point of delivery of patient care is now possible using this approach. It has wide implications for the provision of other types of therapeutic information in clinical areas. Web-based technology represents an opportunity for clinical pharmacologists to provide therapeutic information for clinical colleagues at the bedside. PMID:12100219

Unrealized Promises: Unequal Access, Affordability, and Excellence at Community Colleges in Southern California

ERIC Educational Resources Information Center

Martinez-Wenzl, Mary; Marquez, Rigoberto

2012-01-01

California community colleges are, by design, the only entry point to four-year institutions for the majority of students in the state. Yet, many of these institutions perpetuate racial and class segregation, thus disrupting the California Master Plan for Higher Education's promise of access, equity, and excellence in higher education. This report…

Accessibility Considerations for e-Learning in Ghana

ERIC Educational Resources Information Center

Boateng, John Kwame

2016-01-01

This paper reports on a study that explored the best ways to design e-learning in order to provide better access for adult learners with disabilities. Two districts from the Central Region of Ghana were selected and two major research questions guided the study. The five-point Likert scale was employed between May and August of 2014. The two…

78 FR 26636 - Combined Notice of Filings

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-07

...: 20130429-5050. Comments Due: 5 p.m. ET 5/13/13. Docket Numbers: RP13-823-000. Applicants: CenterPoint... Operational Purchases and Sales Report for 12 Months Ending December 31, 2012. Filed Date: 4/29/13. Accession... Purchases and Sales of Gas Report for 12 Months Ending December 31, 2013. Filed Date: 4/29/13. Accession...

Access to Higher Education in Brazil with Reference to Prouni

ERIC Educational Resources Information Center

de Araujo, Abrahao Andre

2012-01-01

The purpose of this essay is to discuss the Prouni--University for All policy, which has been implemented in Brazil in an effort to increase access of the underprivileged to postsecondary education. In order to provide a better understanding of the problem, three points of interest are initially addressed: income inequality, illiteracy, and a…

Opting in and Creating Demand: Why Young People Choose to Teach Mathematics to Each Other

ERIC Educational Resources Information Center

Tucker-Raymond, Eli; Lewis, Naama; Moses, Maisha; Milner, Chad

2016-01-01

Access to science, technology, engineering, and mathematics fields serves as a key entry point to economic mobility and civic enfranchisement. Such access must take seriously the intellectual power of the knowledge and practices of non-dominant youth. In our case, this has meant to shift epistemic authority in mathematics from academic…

Developing and Managing a Local Digital Archive for Integrated Access to Journals and Other Publications.

ERIC Educational Resources Information Center

Stackpole, Laurie

2001-01-01

The Naval Research Laboratory Library has made significant progress providing its distributed user community with a single point-of-access to information needed to support scientific research through TORPEDO "Ultra," a digital archive that in many respects functions as an electronic counterpart of a traditional library. It consists of…

Utilizing Building Usage Assessment: Determining Deployment of Student Workers in an Academic Library

ERIC Educational Resources Information Center

Buller, Ryan F.

2014-01-01

Generating, collecting, and analyzing building usage statistics can greatly increase the ability of an access services unit to meet the changing dynamic of patron needs in an academic library. By analyzing three different data points, the Access Services Unit in Malpass Library at Western Illinois University was able to determine the most…

[Evaluation of the Andalusia Public Health System hospital websites in the period 2010-2012].

PubMed

de la Torre Barbero, M J; Estepa Luna, M J; López-Pardo Martínez, M; León Márquez, M; Sánchez Laguna, F; Toledano Redondo, S

2014-01-01

Evaluate the quality, accessibility and presence of Web 2.0 tools in the Andalusia Public Health System hospitals websites Observational, descriptive study carried out between 2010 and 2012. The variables analyzed were: quality, accessibility and innovation. The quality was evaluated using a Bermudez-Tamayo questionnaire. Accessibility was measured using the Web Accessibility Test (TAW) tool. Web 2.0 tools were identified by direct observation. A total of 31 of the 45 hospitals (68.9%) had a website in the year 2010, increasing to 34 (75.5%) in 2012. The average score+standard deviation (SD) of the Bermudez-Tamayo quality questionnaire was 11.1+3.8 points in 2010, and 12.3+3.9 points in 2012, observing a statistically significant difference of 0.25 being observed between the means (P=.007), 95% CI; 0.00 to 0.50) In the accessibility evaluation only 7 websites (n=31) in 2010, and 10 (n=34) in 2012, fulfilled the legal criteria for accessibility. The use of Web 2.0 tools has increased throughout the study. In 2010, 19.4% (n=6) of the hospital websites had this type of tool, in comparison to 58.8% (n=20) in 2012. In general, the quality of the websites studied is good. However, current legislation regarding accessibility is not fulfilled and must be revised and adapted to the current legal rules. There is an incipient use of Web 2.0 resources as education and communication strategies with regard to health. Copyright © 2013 SECA. Published by Elsevier Espana. All rights reserved.

How far will they go? Assessing the travel distance of current and former drug users to access harm reduction services.

PubMed

Allen, Sean; Ruiz, Monica; O'Rourke, Allison

2015-03-01

Prior research has explored spatial access to syringe exchange programs (SEPs) among people who inject drugs (PWID), but little is known about service utilization by former PWID who continue to access services (e.g., HIV screenings and referrals for social services) at harm reduction providers. The purpose of this research is to examine differences in access to SEPs between current and former PWID seeking services at a mobile SEP in Washington, DC. A geometric point distance estimation technique was applied to data collected as part of a PWID population estimation study that took place in Washington, DC, in March and April 2014. We calculated the walking distance from the centroid point of home residence zip code to the mobile exchange site where PWID presented for services. An independent samples t-test was used to examine differences in walking distance measures between current and former PWID. Differences in mean walking distance were statistically significant with current and former PWID having mean walking distances of 2.75 and 1.80 miles, respectively. The results of this study suggest that former PWID who are engaging with SEPs primarily for non-needle exchange services (e.g., medical or social services) may have decreased access to SEPs than their counterparts who are active injectors. This research provides support for expanding SEP operations such that both active and former PWID have increased access to harm reduction providers and associated health and social services. Increasing service accessibility may help resolve unmet needs among current and former PWID.

Changes in Utilization and Health Among Low-Income Adults After Medicaid Expansion or Expanded Private Insurance.

PubMed

Sommers, Benjamin D; Blendon, Robert J; Orav, E John; Epstein, Arnold M

2016-10-01

Under the Affordable Care Act (ACA), more than 30 states have expanded Medicaid, with some states choosing to expand private insurance instead (the "private option"). In addition, while coverage gains from the ACA's Medicaid expansion are well documented, impacts on utilization and health are unclear. To assess changes in access to care, utilization, and self-reported health among low-income adults in 3 states taking alternative approaches to the ACA. Differences-in-differences analysis of survey data from November 2013 through December 2015 of US citizens ages 19 to 64 years with incomes below 138% of the federal poverty level in Kentucky, Arkansas, and Texas (n = 8676). Data analysis was conducted between January and May 2016. Medicaid expansion in Kentucky and use of Medicaid funds to purchase private insurance for low-income adults in Arkansas (private option), compared with no expansion in Texas. Self-reported access to primary care, specialty care, and medications; affordability of care; outpatient, inpatient, and emergency utilization; receiving glucose and cholesterol testing, annual check-up, and care for chronic conditions; quality of care, depression score, and overall health. Among the 3 states included in the study, Arkansas (n=2890), Kentucky (n=2898, and Texas (n=2888), there were no differences in sex, income, or marital status. Respondents from Texas were younger, more urban, and disproportionately Latino compared with those in Arkansas and Kentucky. Significant changes in coverage and access were more apparent in 2015 than in 2014. By 2015, expansion was associated with a 22.7 percentage-point reduction in the uninsured rate compared with nonexpansion (P < .001). Expansion was associated with significantly increased access to primary care (12.1 percentage points; P < .001), fewer skipped medications due to cost (-11.6 percentage points; P < .001), reduced out-of-pocket spending (-29.5%; P = .02), reduced likelihood of emergency department visits (-6.0 percentage points, P = .04), and increased outpatient visits (0.69 visits per year; P = .04). Screening for diabetes (6.3 percentage points; P = .05), glucose testing among patients with diabetes (10.7 percentage points; P = .03), and regular care for chronic conditions (12.0 percentage points; P = .008) all increased significantly after expansion. Quality of care ratings improved significantly (-7.1 percentage points with "fair/poor quality of care"; P = .03), as did the share of adults reporting excellent health (4.8 percentage points; P = .04). Comparisons of Arkansas vs Kentucky showed increased private coverage in the former (21.7 percentage points; P < .001), increased Medicaid in the latter (21.3 percentage points; P  < .001), and higher diabetic glucose testing rates in Kentucky (11.6 percentage points; P = .04), but no other statistically significant differences. In the second year of expansion, Kentucky's Medicaid program and Arkansas's private option were associated with significant increases in outpatient utilization, preventive care, and improved health care quality; reductions in emergency department use; and improved self-reported health. Aside from the type of coverage obtained, outcomes were similar for nearly all other outcomes between the 2 states using alternative approaches to expansion.

VIEWCACHE: An incremental pointer-based access method for autonomous interoperable databases

NASA Technical Reports Server (NTRS)

Roussopoulos, N.; Sellis, Timos

1993-01-01

One of the biggest problems facing NASA today is to provide scientists efficient access to a large number of distributed databases. Our pointer-based incremental data base access method, VIEWCACHE, provides such an interface for accessing distributed datasets and directories. VIEWCACHE allows database browsing and search performing inter-database cross-referencing with no actual data movement between database sites. This organization and processing is especially suitable for managing Astrophysics databases which are physically distributed all over the world. Once the search is complete, the set of collected pointers pointing to the desired data are cached. VIEWCACHE includes spatial access methods for accessing image datasets, which provide much easier query formulation by referring directly to the image and very efficient search for objects contained within a two-dimensional window. We will develop and optimize a VIEWCACHE External Gateway Access to database management systems to facilitate database search.

VIEWCACHE: An incremental pointer-based access method for autonomous interoperable databases

NASA Technical Reports Server (NTRS)

Roussopoulos, N.; Sellis, Timos

1992-01-01

One of biggest problems facing NASA today is to provide scientists efficient access to a large number of distributed databases. Our pointer-based incremental database access method, VIEWCACHE, provides such an interface for accessing distributed data sets and directories. VIEWCACHE allows database browsing and search performing inter-database cross-referencing with no actual data movement between database sites. This organization and processing is especially suitable for managing Astrophysics databases which are physically distributed all over the world. Once the search is complete, the set of collected pointers pointing to the desired data are cached. VIEWCACHE includes spatial access methods for accessing image data sets, which provide much easier query formulation by referring directly to the image and very efficient search for objects contained within a two-dimensional window. We will develop and optimize a VIEWCACHE External Gateway Access to database management systems to facilitate distributed database search.

Implementation of envelope detection based Wake-Up Receiver for IEEE 802.15.4 WPAN from off-the-shelf components

NASA Astrophysics Data System (ADS)

Arndt, Josua; Krystofiak, Lukas; Bonehi, Vahid; Wunderlich, Ralf; Heinen, Stefan

2017-09-01

Power consumption in wireless networks is crucial. In most scenarios the transmission time is short compared to the idle listening time for data transmission, the most power is consumed by the receiver. In low latency systems there is a need for low power wake-up receivers (WuRx) that reduce the power consumption when the node is idle, but keep it responsive. This work presents a WuRx designed out of commercial components to investigate the needs of a WuRx when it is embedded in a Wireless Personal Area Network (WPAN) system in a real environment setup including WLAN and LTE communication and considering interferer rejection. The calculation necessary for the attenuation of those interferers is explained in detail. Furthermore, a system design is presented that fulfills the requirements for this environment and is build from off-the-shelf components.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurt Derr; Milos Manic

Location Based Services (LBS), context aware applications, and people and object tracking depend on the ability to locate mobile devices, also known as localization, in the wireless landscape. Localization enables a diverse set of applications that include, but are not limited to, vehicle guidance in an industrial environment, security monitoring, self-guided tours, personalized communications services, resource tracking, mobile commerce services, guiding emergency workers during fire emergencies, habitat monitoring, environmental surveillance, and receiving alerts. This paper presents a new neural network approach (LENSR) based on a competitive topological Counter Propagation Network (CPN) with k-nearest neighborhood vector mapping, for indoor location estimationmore » based on received signal strength. The advantage of this approach is both speed and accuracy. The tested accuracy of the algorithm was 90.6% within 1 meter and 96.4% within 1.5 meters. Several approaches for location estimation using WLAN technology were reviewed for comparison of results.« less

A Double-Negative Metamaterial-Inspired Mobile Wireless Antenna for Electromagnetic Absorption Reduction.

PubMed

Alam, Touhidul; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

2015-07-29

A double-negative metamaterial-inspired antenna is presented for mobile wireless applications. The antenna consists of a semi-circular radiating patch and a 3 × 4 hexagonal shaped metamaterial unit cell array in the ground plane. The antenna is fed with a 50 Ω microstrip feed line. The electric dimensions of the proposed antenna are 0.20λ × 0.26λ × 0.004λ, at the low-end frequency. The proposed antenna achieves a -10 dB impedance with a bandwidth of 2.29 GHz at the lower band and 1.28 GHz at the upper band and can operate for most of the mobile applications such as upper GSM bands, WiMAX, Bluetooth, and wireless local area network (WLAN) frequency bands. The focused novelties of the proposed antenna are its small size, multi-standard operating bands, and electromagnetic absorption reduction at all the operating frequencies using the double-negative metamaterial ground plane.

Compact filtering monopole patch antenna with dual-band rejection.

PubMed

Kim, Sun-Woong; Choi, Dong-You

2016-01-01

In this paper, a compact ultra-wideband patch antenna with dual-band rejection is proposed. The proposed antenna filters 3.3-3.8 GHz WiMAX and 5.15-5.85 GHz WLAN by respectively rejecting these bands through a C-shaped slit and a λg/4 resonator. The λg/4 resonator is positioned as a pair, centered around the microstrip line, and a C-type slit is inserted into an elliptical patch. The impedance bandwidth of the proposed antenna is 2.9-9.3 GHz, which satisfies the bandwidth for ultra-wideband communication systems. Further, the proposed antenna provides dual-band rejection at two bands: 3.2-3.85 and 4.7-6.03 GHz. The radiation pattern of the antenna is omnidirectional, and antenna gain is maintained constantly while showing -8.4 and -1.5 dBi at the two rejected bands, respectively.

Analysis of resonance response performance of C-band antenna using parasitic element.

PubMed

Zaman, M R; Islam, M T; Misran, N; Mandeep, J S

2014-01-01

Analysis of the resonance response improvement of a planar C-band (4-8 GHz) antenna is proposed using parasitic element method. This parasitic element based method is validated for change in the active and parasitic antenna elements. A novel dual-band antenna for C-band application covering 5.7 GHz and 7.6 GHz is designed and fabricated. The antenna is composed of circular parasitic element with unequal microstrip lines at both sides and a rectangular partial ground plane. A fractional bandwidth of 13.5% has been achieved from 5.5 GHz to 6.3 GHz (WLAN band) for the lower band. The upper band covers from 7.1 GHz to 8 GHz with a fractional bandwidth of 12%. A gain of 6.4 dBi is achieved at the lower frequency and 4 dBi is achieved at the upper frequency. The VSWR of the antenna is less than 2 at the resonance frequency.

A Cross-Layer User Centric Vertical Handover Decision Approach Based on MIH Local Triggers

NASA Astrophysics Data System (ADS)

Rehan, Maaz; Yousaf, Muhammad; Qayyum, Amir; Malik, Shahzad

Vertical handover decision algorithm that is based on user preferences and coupled with Media Independent Handover (MIH) local triggers have not been explored much in the literature. We have developed a comprehensive cross-layer solution, called Vertical Handover Decision (VHOD) approach, which consists of three parts viz. mechanism for collecting and storing user preferences, Vertical Handover Decision (VHOD) algorithm and the MIH Function (MIHF). MIHF triggers the VHOD algorithm which operates on user preferences to issue handover commands to mobility management protocol. VHOD algorithm is an MIH User and therefore needs to subscribe events and configure thresholds for receiving triggers from MIHF. In this regard, we have performed experiments in WLAN to suggest thresholds for Link Going Down trigger. We have also critically evaluated the handover decision process, proposed Just-in-time interface activation technique, compared our proposed approach with prominent user centric approaches and analyzed our approach from different aspects.

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

PubMed

Mafole, Prosper; Aritsugi, Masayoshi

2016-01-01

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

Routing architecture and security for airborne networks

NASA Astrophysics Data System (ADS)

Deng, Hongmei; Xie, Peng; Li, Jason; Xu, Roger; Levy, Renato

2009-05-01

Airborne networks are envisioned to provide interconnectivity for terrestial and space networks by interconnecting highly mobile airborne platforms. A number of military applications are expected to be used by the operator, and all these applications require proper routing security support to establish correct route between communicating platforms in a timely manner. As airborne networks somewhat different from traditional wired and wireless networks (e.g., Internet, LAN, WLAN, MANET, etc), security aspects valid in these networks are not fully applicable to airborne networks. Designing an efficient security scheme to protect airborne networks is confronted with new requirements. In this paper, we first identify a candidate routing architecture, which works as an underlying structure for our proposed security scheme. And then we investigate the vulnerabilities and attack models against routing protocols in airborne networks. Based on these studies, we propose an integrated security solution to address routing security issues in airborne networks.

Navigation studies based on the ubiquitous positioning technologies

NASA Astrophysics Data System (ADS)

Ye, Lei; Mi, Weijie; Wang, Defeng

2007-11-01

This paper summarized the nowadays positioning technologies, such as absolute positioning methods and relative positioning methods, indoor positioning and outdoor positioning, active positioning and passive positioning. Global Navigation Satellite System (GNSS) technologies were introduced as the omnipresent out-door positioning technologies, including GPS, GLONASS, Galileo and BD-1/2. After analysis of the shortcomings of GNSS, indoor positioning technologies were discussed and compared, including A-GPS, Cellular network, Infrared, Electromagnetism, Computer Vision Cognition, Embedded Pressure Sensor, Ultrasonic, RFID (Radio Frequency IDentification), Bluetooth, WLAN etc.. Then the concept and characteristics of Ubiquitous Positioning was proposed. After the ubiquitous positioning technologies contrast and selection followed by system engineering methodology, a navigation system model based on Incorporate Indoor-Outdoor Positioning Solution was proposed. And this model was simulated in the Galileo Demonstration for World Expo Shanghai project. In the conclusion, the prospects of ubiquitous positioning based navigation were shown, especially to satisfy the public location information acquiring requirement.

Optimum concentric circular array antenna with high gain and side lobe reduction at 5.8 GHz

NASA Astrophysics Data System (ADS)

Zaid, Mohammed; Rafiqul Islam, Md; Habaebi, Mohamed H.; Zahirul Alam, AHM; Abdullah, Khaizuran

2017-11-01

The significance of high gain directional antennas stems from the need to cope up with the everyday progressing wireless communication systems. Due to low gain of the widely used microstrip antenna, combining multiple antennas in proper geometry increases the gain with good directive property. Over other array forms, this paper uses concentric circular array configuration for its compact structure and inherent symmetry in azimuth. This proposed array is composed of 9 elements on FR-4 substrate, which is designed for WLAN applications at 5.8GHz. Antenna Magus software is used for synthesis, while CST software is used for optimization. The proposed array is designed with optimum inter-element spacing and number of elements achieving a high directional gain of 15.7 dB compared to 14.2 dB of available literature, with a high reduction in side lobe level of -17.6 dB.

High Dielectric Low Loss Transparent Glass Material Based Dielectric Resonator Antenna with Wide Bandwidth Operation

NASA Astrophysics Data System (ADS)

Mehmood, Arshad; Zheng, Yuliang; Braun, Hubertus; Hovhannisyan, Martun; Letz, Martin; Jakoby, Rolf

2015-01-01

This paper presents the application of new high permittivity and low loss glass material for antennas. This glass material is transparent. A very simple rectangular dielectric resonator antenna is designed first with a simple microstrip feeding line. In order to widen the bandwidth, the feed of the design is modified by forming a T-shaped feeding. This new design enhanced the bandwidth range to cover the WLAN 5 GHz band completely. The dielectric resonator antenna cut into precise dimensions is placed on the modified microstrip feed line. The design is simple and easy to manufacture and also very compact in size of only 36 × 28 mm. A -10 dB impedance bandwidth of 18% has been achieved, which covers the frequency range from 5.15 GHz to 5.95 GHz. Simulations of the measured return loss and radiation patterns are presented and discussed.

Polymer (PDMS-Fe3O4) magneto-dielectric substrate for a MIMO antenna array

NASA Astrophysics Data System (ADS)

Alqadami, Abdulrahman Shueai Mohsen; Jamlos, Mohd Faizal; Soh, Ping Jack; Kamarudin, Muhammad Ramlee

2016-01-01

This paper presents the design of a 2 × 4 multiple-input multiple-output (MIMO) antenna array fabricated on a nanocomposite magneto-dielectric polymer substrate. The 10-nm iron oxide (Fe3O4) nanoparticles and polydimethylsiloxane (PDMS) composite is used as substrate to enhance the performance of a MIMO antenna array. The measured results showed up to 40.8 % enhancement in terms of bandwidth, 9.95 dB gain, and 57 % of radiation efficiency. Furthermore, it is found that the proposed magneto-dielectric (PDMS-Fe3O4) composite substrate provides excellent MIMO parameters such as correlation coefficient, diversity gain, and mutual coupling. The prototype of the proposed antenna is transparent, flexible, lightweight, and resistant against dust and corrosion. Measured results indicate that the proposed antenna is suitable for WLAN and ultra-wideband biomedical applications within frequency range of 5.33-7.70 GHz.

Modified Sierpenski Antenna With Metamaterial For Wireless Applications

NASA Astrophysics Data System (ADS)

Aggarwal, Ishita; Pandey, Sujata

2017-08-01

This paper presents a multiband antenna based on modified sierpenski fractal structure along with metamaterials for wireless applications. Multi bands are obtained at 2.1 GHz, 5.73 GHz, 7.6 GHz and 8.4 GHz with return losses -21.49 dB,-36.36 dB,-45dB, and -23.46 dBrespectively. The dimension of the substrate used for this antenna is 52 x 60 x 1.6 mm3 and dielectric constant is 4.4 with tanδ of 0.002. The peak gain of 6.6 dB, return loss of -45 dB and VSWR of 1 are obtained at 7.6 GHz. Metamaterial unit cells are loaded on ground to improve the antenna parameters. This is a simple and compact design and has multiband features suitable for WIMAX, WLAN, C-band and X-band applications. This design is simulated by using HFSS 14.

Miniaturized dual-band antenna array with double-negative (DNG) metamaterial for wireless applications

NASA Astrophysics Data System (ADS)

Alqadami, Abdulrahman Shueai Mohsen; Jamlos, Mohd Faizal; Soh, Ping Jack; Rahim, Sharul Kamal Abdul; Vandenbosch, Guy A. E.; Narbudowicz, Adam

2017-01-01

A miniaturized dual-band antenna array using a negative index metamaterial is presented for WiMAX, LTE, and WLAN applications. This left-handed metamaterial plane is located behind the antenna array, and its unit cell is a combination of split-ring resonator, square electric ring resonator, and rectangular electrical coupled resonator. This enables the achievement of a metamaterial structure exhibiting both negative permittivity and permeability, which results in antenna size miniaturization, efficiency, and gain enhancement. Moreover, the proposed metamaterial antenna has realized dual-band operating frequencies compared to a single frequency for normal antenna. The measured reflection coefficient (S11) shows a 50.25% bandwidth in the lower band (from 2.119 to 3.058 GHz) and 4.27% in the upper band (from 5.058 to 5.276 GHz). Radiation efficiency obtained in the lower and upper band are >95 and 80%, respectively.

Point prevalence of access block and overcrowding in New Zealand emergency departments in 2010 and their relationship to the 'Shorter Stays in ED' target.

PubMed

Jones, Peter G; Olsen, Sarah

2011-10-01

To document the extent of access block and ED overcrowding in New Zealand in 2010 and to determine whether these were linked to the hospital's ability to meet the Shorter Stays in ED target. Surveys of all New Zealand EDs were undertaken at two points in time in 2010 to determine ED occupancy. Data on target achievement during corresponding time periods were obtained from the Ministry of Health. In tertiary and secondary hospitals, respectively, access block was seen in 64% versus 23% (P= 0.05) and overcrowding was seen in 57.1% versus 39% (P= 0.45). No hospital with access block met the 'Shorter Stays' target, compared with 60% without access block (P= 0.001). Twenty-three per cent of hospitals with ED overcrowding met the target compared with 43% without ED overcrowding (P= 0.42). The number of patients experiencing ≥8 h delay to admission were 25 in May and 59 in August (P= 0.04). This represented 45.5% and 79.7% of patients waiting for admission, respectively (P= 0.08). Hospital access block was seen more often in larger hospitals and significantly associated with failure to meet the 'Shorter Stays in ED' health target, whereas ED overcrowding was seen in both small and large hospitals, but not associated with failure to meet the target. © 2011 The Authors. EMA © 2011 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Weight gain in mid-childhood and its relationship with the fast food environment.

PubMed

Pearce, Matthew; Bray, Isabelle; Horswell, Michael

2017-09-10

Childhood obesity is a serious public health issue. Understanding environmental factors and their contribution to weight gain is important if interventions are to be effective. The purpose of this research was to assess the relationship between weight gain in children and accessibility of fast-food outlets. A longitudinal sample of 1577 children was created using two time points from the National Child Measurement Programme in South Gloucestershire (2006/7 and 2012/13). A spatial analysis was conducted using a weighted accessibility score on the number of fast-food outlets within a 1-km network radius of each child's residence to quantify access to fast food. The mean accessibility score for all children was 0.73 (standard deviation: 1.14). Fast-food outlets were more prevalent in areas of deprivation. A moderate association was found between deprivation score and accessibilty score (r = 0.4, P < 0.01). Children who had greater access to fast-food outlets were more likely (odds ratio = 1.89, P = 0.04) to gain significant weight (>50 percentile points) compared to children who had no access to fast-food outlets. This paper supports previous research that fast-food outlets are more prevalent in areas of deprivation and presents new evidence on fast-food outlets as a potential contributor towards weight gain in mid-childhood. © The Author 2017. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Performance Evaluation of Remote Memory Access (RMA) Programming on Shared Memory Parallel Computers

NASA Technical Reports Server (NTRS)

Jin, Hao-Qiang; Jost, Gabriele; Biegel, Bryan A. (Technical Monitor)

2002-01-01

The purpose of this study is to evaluate the feasibility of remote memory access (RMA) programming on shared memory parallel computers. We discuss different RMA based implementations of selected CFD application benchmark kernels and compare them to corresponding message passing based codes. For the message-passing implementation we use MPI point-to-point and global communication routines. For the RMA based approach we consider two different libraries supporting this programming model. One is a shared memory parallelization library (SMPlib) developed at NASA Ames, the other is the MPI-2 extensions to the MPI Standard. We give timing comparisons for the different implementation strategies and discuss the performance.

Spud Point Marina Breakwater, Bodega Bay, Sonoma County, California.

DTIC Science & Technology

1991-07-01

AD-A240 319 ~ MONITORING COMPLETED COASTAL PROJECTS PROGRAM MISCELLANEOUS PAPER CERC-91-5 0SPUD POINT MARINA BREAKWATER, BODEGA BAY SONOMA COUNTY , CALIFORNIA...SUBTITLE S. FUNDING NUMBERS Spud Point Marina Breakwater, Bodega Bay, Sonoma County , WU 22123 California 6. AUTHOR(S) Jonathan W. Lott 7. PERFORMING...of the harbor are also shown. The marina docks and shoreside facilities are oper- ated by Sonoma County . The breakwater and access channel are main

77 FR 25131 - Turning Point Solar LLC: Notice of Finding of No Significant Impact

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-27

... monocrystalline photovoltaic panels mounted on fixed solar racking equipment and the construction of access roads... DEPARTMENT OF AGRICULTURE Rural Utilities Service Turning Point Solar LLC: Notice of Finding of No... Environmental Assessment (EA) associated with a solar generation project. The EA was prepared in accordance with...

1. VIEW, LOOKING SOUTH, OF THE NORTH ELEVATION OF BUILDING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. VIEW, LOOKING SOUTH, OF THE NORTH ELEVATION OF BUILDING 792A. BUILDING 792A, AT PORTAL 3, IS ONE OF THREE PEDESTRIAN ACCESS POINTS THROUGH THE PERIMETER SECURITY ZONE INTO THE PROTECTED AREA. - Rocky Flats Plant, Access Control Building, North of building 771, in parking area 71, just south of North Perimeter Road, Golden, Jefferson County, CO

Using Microsoft Access: A How-To-Do-It Manual for Librarians. How-To-Do-It Manuals for Librarians, Number 76.

ERIC Educational Resources Information Center

Butler, E. Sonny

Much of what librarians do today requires adeptness in creating and manipulating databases. Many new computers bought by libraries every year come packaged with Microsoft Office and include Microsoft Access. This database program features a seamless interface between Microsoft Office's other programs like Word, Excel, and PowerPoint. This book…

Balancing investments in Federally Qualified Health Centers and Medicaid for improved access and coverage in Pennsylvania.

PubMed

Griffin, Paul M; Lee, Hyunji; Scherrer, Christina; Swann, Julie L

2014-12-01

Two common health disparities in the US include a lack of access to care and a lack of insurance coverage. To help address these disparities, healthcare reform will provide $11B to expand Federally Qualified Health Centers (FQHCs) over the next 5 years. In 2014, Medicaid rules will be modified so that more people will become eligible. There are, however, important tradeoffs in the investment in these two programs. We find a balanced investment between FQHC expansion and relaxing Medicaid eligibility to improve both access (by increasing the number of FQHCs) and coverage (by FQHC and Medicaid expansion) for the state of Pennsylvania. The comparison is achieved by integrating multi-objective mathematical models with several public data sets that allow for specific estimations of healthcare need. Demand is estimated based on current access and coverage status in order to target groups to be considered preferentially. Results show that for Pennsylvania, FQHCs are more cost effective than Medicaid if we invest all of the resources in just one policy. However, we find a better investment point balancing those two policies. This point is approximately where the additional expenses incurred from relaxing Medicaid eligibility equals the investment in FQHC expansion.

Pan European Phenological database (PEP725): a single point of access for European data

NASA Astrophysics Data System (ADS)

Templ, Barbara; Koch, Elisabeth; Bolmgren, Kjell; Ungersböck, Markus; Paul, Anita; Scheifinger, Helfried; Rutishauser, This; Busto, Montserrat; Chmielewski, Frank-M.; Hájková, Lenka; Hodzić, Sabina; Kaspar, Frank; Pietragalla, Barbara; Romero-Fresneda, Ramiro; Tolvanen, Anne; Vučetič, Višnja; Zimmermann, Kirsten; Zust, Ana

2018-06-01

The Pan European Phenology (PEP) project is a European infrastructure to promote and facilitate phenological research, education, and environmental monitoring. The main objective is to maintain and develop a Pan European Phenological database (PEP725) with an open, unrestricted data access for science and education. PEP725 is the successor of the database developed through the COST action 725 "Establishing a European phenological data platform for climatological applications" working as a single access point for European-wide plant phenological data. So far, 32 European meteorological services and project partners from across Europe have joined and supplied data collected by volunteers from 1868 to the present for the PEP725 database. Most of the partners actively provide data on a regular basis. The database presently holds almost 12 million records, about 46 growing stages and 265 plant species (including cultivars), and can be accessed via http://www.pep725.eu/ . Users of the PEP725 database have studied a diversity of topics ranging from climate change impact, plant physiological question, phenological modeling, and remote sensing of vegetation to ecosystem productivity.

Relationship between household access to food and malnutrition in eastern and southern Africa.

PubMed

Mwadime, R K; Baldwin, S L

1994-09-01

This review paper gives an overview of the relationship between household access to food and malnutrition using national level data in the Eastern and Southern Africa Region. The overall prevalence of malnutrition amongst the under-five population have not changed significantly over the decade and, in some cases, have deteriorated. The situation of household access to food differs between economies and production systems, but most households (average of 80%) in the region do not have access to adequate food. A preliminary analysis of the determinants of malnutrition at country level pointed to the importance of: financial access to food (an indicator of household access to food) and; access to safe water (an indicator of household healthy environment), as the most significant variables predicting rates of malnutrition. Several areas for action by governments in the region and for further study within the subject of household access to food are delineated. These are: more clear determination of the relative contribution of household access to food, to the nutritional status of women and children and, improved analysis of indicators of household access to food.

Ultrafast random-access scanning in two-photon microscopy using acousto-optic deflectors.

PubMed

Salomé, R; Kremer, Y; Dieudonné, S; Léger, J-F; Krichevsky, O; Wyart, C; Chatenay, D; Bourdieu, L

2006-06-30

Two-photon scanning microscopy (TPSM) is a powerful tool for imaging deep inside living tissues with sub-cellular resolution. The temporal resolution of TPSM is however strongly limited by the galvanometric mirrors used to steer the laser beam. Fast physiological events can therefore only be followed by scanning repeatedly a single line within the field of view. Because acousto-optic deflectors (AODs) are non-mechanical devices, they allow access at any point within the field of view on a microsecond time scale and are therefore excellent candidates to improve the temporal resolution of TPSM. However, the use of AOD-based scanners with femtosecond pulses raises several technical difficulties. In this paper, we describe an all-digital TPSM setup based on two crossed AODs. It includes in particular an acousto-optic modulator (AOM) placed at 45 degrees with respect to the AODs to pre-compensate for the large spatial distortions of femtosecond pulses occurring in the AODs, in order to optimize the spatial resolution and the fluorescence excitation. Our setup allows recording from freely selectable point-of-interest at high speed (1kHz). By maximizing the time spent on points of interest, random-access TPSM (RA-TPSM) constitutes a promising method for multiunit recordings with millisecond resolution in biological tissues.

On Increasing Network Lifetime in Body Area Networks Using Global Routing with Energy Consumption Balancing

PubMed Central

Tsouri, Gill R.; Prieto, Alvaro; Argade, Nikhil

2012-01-01

Global routing protocols in wireless body area networks are considered. Global routing is augmented with a novel link cost function designed to balance energy consumption across the network. The result is a substantial increase in network lifetime at the expense of a marginal increase in energy per bit. Network maintenance requirements are reduced as well, since balancing energy consumption means all batteries need to be serviced at the same time and less frequently. The proposed routing protocol is evaluated using a hardware experimental setup comprising multiple nodes and an access point. The setup is used to assess network architectures, including an on-body access point and an off-body access point with varying number of antennas. Real-time experiments are conducted in indoor environments to assess performance gains. In addition, the setup is used to record channel attenuation data which are then processed in extensive computer simulations providing insight on the effect of protocol parameters on performance. Results demonstrate efficient balancing of energy consumption across all nodes, an average increase of up to 40% in network lifetime corresponding to a modest average increase of 0.4 dB in energy per bit, and a cutoff effect on required transmission power to achieve reliable connectivity. PMID:23201987

On increasing network lifetime in body area networks using global routing with energy consumption balancing.

PubMed

Tsouri, Gill R; Prieto, Alvaro; Argade, Nikhil

2012-09-26

Global routing protocols in wireless body area networks are considered. Global routing is augmented with a novel link cost function designed to balance energy consumption across the network. The result is a substantial increase in network lifetime at the expense of a marginal increase in energy per bit. Network maintenance requirements are reduced as well, since balancing energy consumption means all batteries need to be serviced at the same time and less frequently. The proposed routing protocol is evaluated using a hardware experimental setup comprising multiple nodes and an access point. The setup is used to assess network architectures, including an on-body access point and an off-body access point with varying number of antennas. Real-time experiments are conducted in indoor environments to assess performance gains. In addition, the setup is used to record channel attenuation data which are then processed in extensive computer simulations providing insight on the effect of protocol parameters on performance. Results demonstrate efficient balancing of energy consumption across all nodes, an average increase of up to 40% in network lifetime corresponding to a modest average increase of 0.4 dB in energy per bit, and a cutoff effect on required transmission power to achieve reliable connectivity.

The Effects of Hurricane Katrina on Food Access Disparities in New Orleans

PubMed Central

Bodor, J. Nicholas; Rice, Janet C.; Swalm, Chris M.; Hutchinson, Paul L.

2011-01-01

Disparities in neighborhood food access are well documented, but little research exists on how shocks influence such disparities. We examined neighborhood food access in New Orleans at 3 time points: before Hurricane Katrina (2004–2005), in 2007, and in 2009. We combined existing directories with on-the-ground verification and geographic information system mapping to assess supermarket counts in the entire city. Existing disparities for African American neighborhoods worsened after the storm. Although improvements have been made, by 2009 disparities were no better than prestorm levels. PMID:21233432

Using Speech Recognition to Enhance the Tongue Drive System Functionality in Computer Access

PubMed Central

Huo, Xueliang; Ghovanloo, Maysam

2013-01-01

Tongue Drive System (TDS) is a wireless tongue operated assistive technology (AT), which can enable people with severe physical disabilities to access computers and drive powered wheelchairs using their volitional tongue movements. TDS offers six discrete commands, simultaneously available to the users, for pointing and typing as a substitute for mouse and keyboard in computer access, respectively. To enhance the TDS performance in typing, we have added a microphone, an audio codec, and a wireless audio link to its readily available 3-axial magnetic sensor array, and combined it with a commercially available speech recognition software, the Dragon Naturally Speaking, which is regarded as one of the most efficient ways for text entry. Our preliminary evaluations indicate that the combined TDS and speech recognition technologies can provide end users with significantly higher performance than using each technology alone, particularly in completing tasks that require both pointing and text entry, such as web surfing. PMID:22255801

A performance comparison of the IBM RS/6000 and the Astronautics ZS-1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, W.M.; Abraham, S.G.; Davidson, E.S.

1991-01-01

Concurrent uniprocessor architectures, of which vector and superscalar are two examples, are designed to capitalize on fine-grain parallelism. The authors have developed a performance evaluation method for comparing and improving these architectures, and in this article they present the methodology and a detailed case study of two machines. The runtime of many programs is dominated by time spent in loop constructs - for example, Fortran Do-loops. Loops generally comprise two logical processes: The access process generates addresses for memory operations while the execute process operates on floating-point data. Memory access patterns typically can be generated independently of the data inmore » the execute process. This independence allows the access process to slip ahead, thereby hiding memory latency. The IBM 360/91 was designed in 1967 to achieve slip dynamically, at runtime. One CPU unit executes integer operations while another handles floating-point operations. Other machines, including the VAX 9000 and the IBM RS/6000, use a similar approach.« less

An objective approach to determining the weight ranges of prey preferred by and accessible to the five large African carnivores.

PubMed

Clements, Hayley S; Tambling, Craig J; Hayward, Matt W; Kerley, Graham I H

2014-01-01

Broad-scale models describing predator prey preferences serve as useful departure points for understanding predator-prey interactions at finer scales. Previous analyses used a subjective approach to identify prey weight preferences of the five large African carnivores, hence their accuracy is questionable. This study uses a segmented model of prey weight versus prey preference to objectively quantify the prey weight preferences of the five large African carnivores. Based on simulations of known predator prey preference, for prey species sample sizes above 32 the segmented model approach detects up to four known changes in prey weight preference (represented by model break-points) with high rates of detection (75% to 100% of simulations, depending on number of break-points) and accuracy (within 1.3±4.0 to 2.7±4.4 of known break-point). When applied to the five large African carnivores, using carnivore diet information from across Africa, the model detected weight ranges of prey that are preferred, killed relative to their abundance, and avoided by each carnivore. Prey in the weight ranges preferred and killed relative to their abundance are together termed "accessible prey". Accessible prey weight ranges were found to be 14-135 kg for cheetah Acinonyx jubatus, 1-45 kg for leopard Panthera pardus, 32-632 kg for lion Panthera leo, 15-1600 kg for spotted hyaena Crocuta crocuta and 10-289 kg for wild dog Lycaon pictus. An assessment of carnivore diets throughout Africa found these accessible prey weight ranges include 88±2% (cheetah), 82±3% (leopard), 81±2% (lion), 97±2% (spotted hyaena) and 96±2% (wild dog) of kills. These descriptions of prey weight preferences therefore contribute to our understanding of the diet spectrum of the five large African carnivores. Where datasets meet the minimum sample size requirements, the segmented model approach provides a means of determining, and comparing, the prey weight range preferences of any carnivore species.

Motorcycles entering from access points and merging with traffic on primary roads in Malaysia: behavioral and road environment influence on the occurrence of traffic conflicts.

PubMed

Abdul Manan, Muhammad Marizwan

2014-09-01

This paper uses data from an observational study, conducted at access points in straight sections of primary roads in Malaysia in 2012, to investigate the effects of motorcyclists' behavior and road environment attributes on the occurrence of serious traffic conflicts involving motorcyclists entering primary roads via access points. In order to handle the unobserved heterogeneity in the small sample data size, this study applies mixed effects logistic regression with multilevel bootstrapping. Two statistically significant models (Model 2 and Model 3) are produced, with 2 levels of random effect parameters, i.e. motorcyclists' attributes and behavior at Level 1, and road environment attributes at Level 2. Among all the road environment attributes tested, the traffic volume and the speed limit are found to be statistically significant, only contributing to 26-29% of the variations affecting the traffic conflict outcome. The implication is that 71-74% of the unmeasured or undescribed attributes and behavior of motorcyclists still have an importance in predicting the outcome: a serious traffic conflict. As for the fixed effect parameters, both models show that the risk of motorcyclists being involved in a serious traffic conflict is 2-4 times more likely if they accept a shorter gap to a single approaching vehicle (time lag <4s) and in between two vehicles (time gap <4s) when entering the primary road from the access point. A road environment factor, such as a narrow lane (seen in Model 2), and a behavioral factor, such as stopping at the stop line (seen in Model 3), also influence the occurrence of a serious traffic conflict compared to those entering into a wider lane road and without stopping at the stop line, respectively. A discussion of the possible reasons for this seemingly strange result, including a recommendation for further research, concludes the paper. Copyright © 2014 Elsevier Ltd. All rights reserved.

Patients' perspectives of accessibility and digital delivery of factual content provided by official medical and surgical specialty society websites: a qualitative assessment.

PubMed

Ow, Darren; Wetherell, David; Papa, Nathan; Bolton, Damien; Lawrentschuk, Nathan

2015-03-27

Health care websites provide a valuable resource of health information to online consumers, especially patients. Official surgical and medical society websites should be a reliable first point of contact. The primary aim of this study was to quantitatively assess medical and surgical society websites for content and highlight the essential features required for a high-quality, user-friendly society website. Twenty specialty association websites from each of the regions, Australia, UK, Canada, Europe, and the USA were selected for a total of 100 websites. Medical and surgical specialities were consistent across each region. Each website was systematically and critically analysed for content and usability. The average points scored per website was 3.2 out of 10. Of the total (N=100) websites, 12 scored at least 7 out of 10 points and 2 scored 9 out of 10. As well, 35% (35.0/100) of the websites had an information tab for patients on their respective homepages while 38% (38.0/100) had download access to patient information. A minority of the websites included different forms of multimedia such as pictures and diagrams (24.0/100, 24%) and videos (18.0/100, 18%). We found that most society websites did not meet an adequate standard for delivery of information. Half of the websites were not patient accessible, with the primary focus being for health professionals. As well, most required logins for information access. Specialty health care societies should create patient-friendly websites that would be beneficial to all online consumers.

Scalable and Resilient Middleware to Handle Information Exchange during Environment Crisis

NASA Astrophysics Data System (ADS)

Tao, R.; Poslad, S.; Moßgraber, J.; Middleton, S.; Hammitzsch, M.

2012-04-01

The EU FP7 TRIDEC project focuses on enabling real-time, intelligent, information management of collaborative, complex, critical decision processes for earth management. A key challenge is to promote a communication infrastructure to facilitate interoperable environment information services during environment events and crises such as tsunamis and drilling, during which increasing volumes and dimensionality of disparate information sources, including sensor-based and human-based ones, can result, and need to be managed. Such a system needs to support: scalable, distributed messaging; asynchronous messaging; open messaging to handling changing clients such as new and retired automated system and human information sources becoming online or offline; flexible data filtering, and heterogeneous access networks (e.g., GSM, WLAN and LAN). In addition, the system needs to be resilient to handle the ICT system failures, e.g. failure, degradation and overloads, during environment events. There are several system middleware choices for TRIDEC based upon a Service-oriented-architecture (SOA), Event-driven-Architecture (EDA), Cloud Computing, and Enterprise Service Bus (ESB). In an SOA, everything is a service (e.g. data access, processing and exchange); clients can request on demand or subscribe to services registered by providers; more often interaction is synchronous. In an EDA system, events that represent significant changes in state can be processed simply, or as streams or more complexly. Cloud computing is a virtualization, interoperable and elastic resource allocation model. An ESB, a fundamental component for enterprise messaging, supports synchronous and asynchronous message exchange models and has inbuilt resilience against ICT failure. Our middleware proposal is an ESB based hybrid architecture model: an SOA extension supports more synchronous workflows; EDA assists the ESB to handle more complex event processing; Cloud computing can be used to increase and decrease the ESB resources on demand. To reify this hybrid ESB centric architecture, we will adopt two complementary approaches: an open source one for scalability and resilience improvement while a commercial one can be used for ultra-speed messaging, whilst we can bridge between these two to support interoperability. In TRIDEC, to manage such a hybrid messaging system, overlay and underlay management techniques will be adopted. The managers (both global and local) will collect, store and update status information (e.g. CPU utilization, free space, number of clients) and balance the usage, throughput, and delays to improve resilience and scalability. The expected resilience improvement includes dynamic failover, self-healing, pre-emptive load balancing, and bottleneck prediction while the expected improvement for scalability includes capacity estimation, Http Bridge, and automatic configuration and reconfiguration (e.g. add or delete clients and servers).

Report of the Defense Science Board Task Force on Defensive Information Operations. 2000 Summer Study. Volume II

DTIC Science & Technology

2001-03-01

distinguishing between attacks and other events such as accidents, system failures, or hacking by thrill-seekers. This challenge is exacerbated by the...and is referred to as Signaling System # 7 ( SS7 ). Commercial Intelligent Network Architecture Switching Signal Point (SSP) Service - Originates...Wireless access point to fixed infrastructure Ut c Signaling Transfer Point (STP) - Packet switch in CCITT#7 Network SP SW SS7 System Data Bases Network

ClinicalKey 2.0: Upgrades in a Point-of-Care Search Engine.

PubMed

Huslig, Mary Ann; Vardell, Emily

2015-01-01

ClinicalKey 2.0, launched September 23, 2014, offers a mobile-friendly design with a search history feature for targeting point-of-care resources for health care professionals. Browsing is improved with searchable, filterable listings of sources highlighting new resources. ClinicalKey 2.0 improvements include more than 1,400 new Topic Pages for quick access to point-of-care content. A sample search details some of the upgrades and content options.

Analysis of EUVE Experiment Results

NASA Technical Reports Server (NTRS)

Horan, Stephen

1996-01-01

A series of tests to validate an antenna pointing concept for spin-stabilized satellites using a data relay satellite are described. These tests show that proper antenna pointing on an inertially-stabilized spacecraft can lead to significant access time through the relay satellite even without active antenna pointing. We summarize the test results, the simulations to model the effects of antenna pattern and space loss, and the expected contact times. We also show how antenna beam width affects the results.

Accuracy assessment of minimum control points for UAV photography and georeferencing

NASA Astrophysics Data System (ADS)

Skarlatos, D.; Procopiou, E.; Stavrou, G.; Gregoriou, M.

2013-08-01

In recent years, Autonomous Unmanned Aerial Vehicles (AUAV) became popular among researchers across disciplines because they combine many advantages. One major application is monitoring and mapping. Their ability to fly beyond eye sight autonomously, collecting data over large areas whenever, wherever, makes them excellent platform for monitoring hazardous areas or disasters. In both cases rapid mapping is needed while human access isn't always a given. Indeed, current automatic processing of aerial photos using photogrammetry and computer vision algorithms allows for rapid orthophomap production and Digital Surface Model (DSM) generation, as tools for monitoring and damage assessment. In such cases, control point measurement using GPS is either impossible, or time consuming or costly. This work investigates accuracies that can be attained using few or none control points over areas of one square kilometer, in two test sites; a typical block and a corridor survey. On board GPS data logged during AUAV's flight are being used for direct georeferencing, while ground check points are being used for evaluation. In addition various control point layouts are being tested using bundle adjustment for accuracy evaluation. Results indicate that it is possible to use on board single frequency GPS for direct georeferencing in cases of disaster management or areas without easy access, or even over featureless areas. Due to large numbers of tie points in the bundle adjustment, horizontal accuracy can be fulfilled with a rather small number of control points, but vertical accuracy may not.

Curriculum/Resource Development: The "C.A.R.E for St. Lucia" Resource Pack.

ERIC Educational Resources Information Center

Strong, Michelle

1993-01-01

Describes a resource packet that utilizes a four-point approach to make environmental action concerning land use more accessible to teachers. The points are construct a map of the area under consideration; assess the impact of historical development, natural cycles, mining, and eco-tourism on the problem; research land use options; and encourage…

Dissemination of a Multilevel Evidence-Based System of Parenting Interventions with Broad Application to Child Welfare Populations

ERIC Educational Resources Information Center

Prinz, Ron

2009-01-01

Parenting interventions are relevant to many touch points of the child welfare system. This paper describes a multilevel system of parenting interventions called "Triple P" that matches intervention intensities to families, builds on a strong scientific base, provides multiple access points for parents, and offers a destigmatized, cost-efficient…

A Success Model for Low-Income Students

ERIC Educational Resources Information Center

Wilt, Richard W.

2006-01-01

Today's community college serves as the entry point to well-paying technical jobs as well as the entry point to the baccalaureate degree and beyond. What, then, can be done to ensure that low-income students have access to and success in community colleges? Research, both theoretical and empirical, shows that there is no one student characteristic…

Designing a Virtual Classroom for Distance Learning Students through the Internet.

ERIC Educational Resources Information Center

Bradshaw, Allen

Advantages to using the Internet to deliver instruction include the fact that Hypertext Markup Language (HTML) can be accessed on any computer, broadening the student base to anyone with an Internet browser and a PPP (Point-to-Point Protocol) account. In addition, instructions, lectures, and examples can be linked together for use as students need…

Mobile Cubesat Command and Control (Mc3) 3-Meter Dish Calibration and Capabilities

DTIC Science & Technology

2014-06-01

accuracy of this simple calibration is tested by tracking the sun, an easily accessible celestial body. To track the sun, a Systems Tool Kit ( STK ... visually verified. The shadow created by the dish system when it is pointed directly at the sun is symmetrical. If the dish system is not pointed

Effects of School-Based Point-of-Testing Counselling on Health Status Variables among Rural Adolescents

ERIC Educational Resources Information Center

Murimi, Mary W.; Chrisman, Matthew S.; Hughes, Kelly; Taylor, Chris; Kim, Yeonsoo; McAllister, Tiffany L.

2015-01-01

Objective: Rural areas may suffer from a lack of access to health care and programmes to promote behaviours such as healthy eating and physical activity. Point-of-testing counselling is a method of promoting a healthy lifestyle during an individual's most "teachable moment". Design/Setting: This longitudinal study examined the effects of…

Point-to-point people with purpose—Exploring the possibility of a commercial traveler market for point-to-point suborbital space transportation

NASA Astrophysics Data System (ADS)

Webber, Derek

2013-12-01

An argument was made at the First Arcachon Conference on Private Human Access to Space in 2008 [1] that some systematic market research should be conducted into potential market segments for point-to-point suborbital space transportation (PtP), in order to understand whether a commercial market exists which might augment possible government use for such a vehicle. The cargo market potential was subsequently addressed via desk research, and the results, which resulted in a pessimistic business case outlook, were presented in [2]. The same desk research approach is now used in this paper to address the potential business and wealthy individual passenger traveler market segment ("point-to-point people with purpose"). The results, with the assumed ticket pricing, are not encouraging.

Mechanical code comparator

DOEpatents

Peter, Frank J.; Dalton, Larry J.; Plummer, David W.

2002-01-01

A new class of mechanical code comparators is described which have broad potential for application in safety, surety, and security applications. These devices can be implemented as micro-scale electromechanical systems that isolate a secure or otherwise controlled device until an access code is entered. This access code is converted into a series of mechanical inputs to the mechanical code comparator, which compares the access code to a pre-input combination, entered previously into the mechanical code comparator by an operator at the system security control point. These devices provide extremely high levels of robust security. Being totally mechanical in operation, an access control system properly based on such devices cannot be circumvented by software attack alone.

Fixed point Open Ocean Observatory network (FixO3): Multidisciplinary observations from the air-sea interface to the deep seafloor

NASA Astrophysics Data System (ADS)

Lampitt, Richard; Cristini, Luisa

2014-05-01

The Fixed point Open Ocean Observatory network (FixO3) seeks to integrate the 23 European open ocean fixed point observatories and to improve access to these key installations for the broader community. These will provide multidisciplinary observations in all parts of the oceans from the air-sea interface to the deep seafloor. Coordinated by the National Oceanography Centre, UK, FixO3 builds on the significant advances achieved through the previous Europe-funded FP7 programmes EuroSITES, ESONET and CARBOOCEAN. Started in September 2013 with a budget of 7 Million Euros over 4 years the project has 29 partners drawn from academia, research institutions and SME's. In addition 12 international experts from a wide range of disciplines comprise an Advisory Board. On behalf of the FixO3 Consortium, we present the programme that will be achieved through the activities of 12 Work Packages: 1. Coordination activities to integrate and harmonise the current procedures and processes. Strong links will be fostered with the wider community across academia, industry, policy and the general public through outreach, knowledge exchange and training. 2. Support actions to offer a) free access to observatory infrastructures to those who do not have such access, and b) free and open data services and products. 3. Joint research activities to innovate and enhance the current capability for multidisciplinary in situ ocean observation. Support actions include Transnational Access (TNA) to FixO3 infrastructure, meaning that European organizations can apply to free-of-charge access to the observatories for research and testing in two international calls during the project lifetime. The first call for TNA opens in summer 2014. More information can be found on FixO3 website (www.fixo3.eu/). Open ocean observation is currently a high priority for European marine and maritime activities. FixO3 will provide important data on environmental products and services to address the Marine Strategy Framework Directive and in support of the European Integrated Maritime Policy. The FixO3 network will provide free and open access to in situ fixed point data of the highest quality. It will provide a strong integrated framework of open ocean facilities in the Atlantic from the Arctic to the Antarctic and throughout the Mediterranean, enabling an integrated, regional and multidisciplinary approach to understand natural and anthropogenic change in the ocean.

Finding Food Deserts: A Comparison of Methods Measuring Spatial Access to Food Stores.

PubMed

Jaskiewicz, Lara; Block, Daniel; Chavez, Noel

2016-05-01

Public health research has increasingly focused on how access to resources affects health behaviors. Mapping environmental factors, such as distance to a supermarket, can identify intervention points toward improving food access in low-income and minority communities. However, the existing literature provides little guidance on choosing the most appropriate measures of spatial access. This study compared the results of different measures of spatial access to large food stores and the locations of high and low access identified by each. The data set included U.S. Census population data and the locations of large food stores in the six-county area around Chicago, Illinois. Six measures of spatial access were calculated at the census block group level and the results compared. The analysis found that there was little agreement in the identified locations of high or low access between measures. This study illustrates the importance of considering the access measure used when conducting research, interpreting results, or comparing studies. Future research should explore the correlation of different measures with health behaviors and health outcomes. © 2015 Society for Public Health Education.

Internet Access as a Structural Factor in Career Choice: A Comparison between Computing and Non-Computing Major Students

ERIC Educational Resources Information Center

Lotriet, Hugo; Matthee, Machdel; Alexander, Patricia

2011-01-01

The career choice model of Adya and Kaiser posits the availability of technology resources as a structural element impacting on career choice. The model distinguishes between accessibility at school and at home. Based on this theoretical point of departure and by arguing a link between choice of major and choice of field of career, this paper…

Architecture and System Engineering Development Study of Space-Based Satellite Networks for NASA Missions

NASA Technical Reports Server (NTRS)

Ivancic, William D.

2003-01-01

Traditional NASA missions, both near Earth and deep space, have been stovepipe in nature and point-to-point in architecture. Recently, NASA and others have conceptualized missions that required space-based networking. The notion of networks in space is a drastic shift in thinking and requires entirely new architectures, radio systems (antennas, modems, and media access), and possibly even new protocols. A full system engineering approach for some key mission architectures will occur that considers issues such as the science being performed, stationkeeping, antenna size, contact time, data rates, radio-link power requirements, media access techniques, and appropriate networking and transport protocols. This report highlights preliminary architecture concepts and key technologies that will be investigated.

Neighborhood Socioeconomic Status and Primary Health Care: Usual Points of Access and Temporal Trends in a Major US Urban Area.

PubMed

Hussein, Mustafa; Diez Roux, Ana V; Field, Robert I

2016-12-01

Neighborhood socioeconomic status (SES), an overall marker of neighborhood conditions, may determine residents' access to health care, independently of their own individual characteristics. It remains unclear, however, how the distinct settings where individuals seek care vary by neighborhood SES, particularly in US urban areas. With existing literature being relatively old, revealing how these associations might have changed in recent years is also timely in this US health care reform era. Using data on the Philadelphia region from 2002 to 2012, we performed multilevel analysis to examine the associations of neighborhood SES (measured as census tract median household income) with access to usual sources of primary care (physician offices, community health centers, and hospital outpatient clinics). We found no evidence that residence in a low-income (versus high-income) neighborhood was associated with poorer overall access. However, low-income neighborhood residence was associated with less reliance on physician offices [-4.40 percentage points; 95 % confidence intervals (CI) -5.80, -3.00] and greater reliance on the safety net provided by health centers [2.08; 95 % CI 1.42, 2.75] and outpatient clinics [1.61; 95 % CI 0.97, 2.26]. These patterns largely persisted over the 10 years investigated. These findings suggest that safety-net providers have continued to play an important role in ensuring access to primary care in urban, low-income communities, further underscoring the importance of supporting a strong safety net to ensure equitable access to care regardless of place of residence.

Insilico modeling and molecular dynamic simulation of claudin-1 point mutations in HCV infection.

PubMed

Vipperla, Bhavaniprasad; Dass, J Febin Prabhu; Jayanthi, S

2014-01-01

Claudin-1 (CLDN1) in association with envelope glycoprotein (CD81) mediates the fusion of HCV into the cytosol. Recent studies have indicated that point mutations in CLDN1 are important for the entry of hepatitis C virus (HCV). To validate these findings, we employed a computational platform to investigate the structural effect of two point mutations (I32M and E48K). Initially, three-dimensional co-ordinates for CLDN1 receptor sequence were generated. Then, three mutant models were built using the point mutation including a double mutant (I32M/E48K) model from the native model structure. Finally, all the four model structures including the native and three mutant models were subjected to molecular dynamics (MD) simulation for a period of 25 ns to appreciate their dynamic behavior. The MD trajectory files were analyzed using cluster and principal component method. The analysis suggested that either of the single mutation has negligible effect on the overall structure of CLDN1 compared to the double mutant form. However, the double mutant model of CLDN1 shows significant negative impact through the impairment of H-bonds and the simultaneous increase in solvent accessible surface area. Our simulation results are visibly consistent with the experimental report suggesting that the CLDN1 receptor distortion is prominent due to the double mutation with large surface accessibility. This increase in accessible surface area due to the coexistence of double mutation may be presumed as one of the key factor that results in permissive action of HCV attachment and infection.

Unravelling relationships: Hospital occupancy levels, discharge timing and emergency department access block.

PubMed

Khanna, Sankalp; Boyle, Justin; Good, Norm; Lind, James

2012-10-01

To investigate the effect of hospital occupancy levels on inpatient and ED patient flow parameters, and to simulate the impact of shifting discharge timing on occupancy levels. Retrospective analysis of hospital inpatient data and ED data from 23 reporting public hospitals in Queensland, Australia, across 30 months. Relationships between outcome measures were explored through the aggregation of the historic data into 21 912 hourly intervals. Main outcome measures included admission and discharge rates, occupancy levels, length of stay for admitted and emergency patients, and the occurrence of access block. The impact of shifting discharge timing on occupancy levels was quantified using observed and simulated data. The study identified three stages of system performance decline, or choke points, as hospital occupancy increased. These choke points were found to be dependent on hospital size, and reflect a system change from 'business-as-usual' to 'crisis'. Effecting early discharge of patients was also found to significantly (P < 0.001) impact overcrowding levels and improve patient flow. Modern hospital systems have the ability to operate efficiently above an often-prescribed 85% occupancy level, with optimal levels varying across hospitals of different size. Operating over these optimal levels leads to performance deterioration defined around occupancy choke points. Understanding these choke points and designing strategies around alleviating these flow bottlenecks would improve capacity management, reduce access block and improve patient outcomes. Effecting early discharge also helps alleviate overcrowding and related stress on the system. © 2012 CSIRO. EMA © 2012 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Research on an uplink carrier sense multiple access algorithm of large indoor visible light communication networks based on an optical hard core point process.

PubMed

Nan, Zhufen; Chi, Xuefen

2016-12-20

The IEEE 802.15.7 protocol suggests that it could coordinate the channel access process based on the competitive method of carrier sensing. However, the directionality of light and randomness of diffuse reflection would give rise to a serious imperfect carrier sense (ICS) problem [e.g., hidden node (HN) problem and exposed node (EN) problem], which brings great challenges in realizing the optical carrier sense multiple access (CSMA) mechanism. In this paper, the carrier sense process implemented by diffuse reflection light is modeled as the choice of independent sets. We establish an ICS model with the presence of ENs and HNs for the multi-point to multi-point visible light communication (VLC) uplink communications system. Considering the severe optical ICS problem, an optical hard core point process (OHCPP) is developed, which characterizes the optical CSMA for the indoor VLC uplink communications system. Due to the limited coverage of the transmitted optical signal, in our OHCPP, the ENs within the transmitters' carrier sense region could be retained provided that they could not corrupt the ongoing communications. Moreover, because of the directionality of both light emitting diode (LED) transmitters and receivers, theoretical analysis of the HN problem becomes difficult. In this paper, we derive the closed-form expression for approximating the outage probability and transmission capacity of VLC networks with the presence of HNs and ENs. Simulation results validate the analysis and also show the existence of an optimal physical carrier-sensing threshold that maximizes the transmission capacity for a given emission angle of LED.

Consumer trust in the Australian food system - The everyday erosive impact of food labelling.

PubMed

Tonkin, Emma; Webb, Trevor; Coveney, John; Meyer, Samantha B; Wilson, Annabelle M

2016-08-01

Consumer trust in food system actors is foundational for ensuring consumer confidence in food safety. As food labelling is a direct communication between consumers and food system actors, it may influence consumer perceptions of actor trustworthiness. This study explores the judgements formed about the trustworthiness of the food system and its actors through labelling, and the expectations these judgements are based on. In-depth, semi-structured interviews with 24 Australian consumers were conducted. Theoretical sampling focussed on shopping location, dietary requirements, rurality, gender, age and educational background. The methodological approach used (adaptive theory) enabled emerging data to be examined through the lens of a set of guiding theoretical concepts, and theory reconsidered in light of emerging data. Food labelling acted as a surrogate for personal interaction with industry and government for participants. Judgements about the trustworthiness of these actors and the broader food system were formed through interaction with food labelling and were based on expectations of both competence and goodwill. Interaction with labelling primarily reduced trust in actors within the food system, undermining trust in the system as a whole. Labelling has a role as an access point to the food system. Access points are points of vulnerability for systems, where trust can be developed, reinforced or broken down. For the participants in this study, in general labelling demonstrates food system actors lack goodwill and violate their fiduciary responsibility. This paper provides crucial insights for industry and policy actors to use this access point to build, rather than undermine, trust in food systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Non-Gimbaled Antenna Pointing

NASA Technical Reports Server (NTRS)

Vigil, Jeannine S.

1997-01-01

The small satellite community has been interested in accessing fixed ground stations for means of space-to-ground transmissions, although a problem arises from the limited global coverage. There is a growing interest for using the Space Network (SN) or Tracking and Data Relay Satellites (TDRS) as the primary support for communications because of the coverage it provides. This thesis will address the potential for satellite access of the Space Network with a non-gimbaled antenna configuration and low-power, coded transmission. The non-gimbaled antenna and the TDRS satellites, TDRS-East, TDRS-West, and TDRS-Zone of Exclusion, were configured in an orbital analysis software package called Satellite Tool Kit to emulate the three-dimensional position of the satellites. The access potential, which is the average number of contacts per day and the average time per contact, were obtained through simulations run over a 30-day period to gain all the possible orientations. The orbital altitude was varied from 600 km through 1200 km with the results being a function of orbital inclination angles varying from 20 deg through 100 deg and pointing half-angles of I0 deg through 40 deg. To compare the validity of the simulations, Jet Propulsion Laboratory granted the use of the TOPEX satellite. The TOPEX satellite was configured to emulate a spin-stabilized antenna with its communications antenna stowed in the zenith-pointing direction. This mimicked the antenna pointing spin-stabilized satellite in the simulations. To make valid comparisons, the TOPEX orbital parameters were entered into Satellite Tool Kit and simulated over five test times provided by Jet Propulsion Laboratory.

Nation Before Service: The Evolution of Joint Operations to a Capabilities-Based Mindset

DTIC Science & Technology

2013-06-01

Identified as one of America’s acupuncture points, cyberspace represents the soft underbelly that facilitates a majority of the world and US economy.90...Corpus, “America’s Acupuncture Points,” Asia Times Online (20 October 2006), http://www.atimes.com/atimes/China/HJ19Ad01.html (accessed 28 December...2012). See also, Zimet and Barry, “Military Service,” 287. 91 Corpus, “America’s Acupuncture Points,” 1. 62 and futurist Ray Kurzweil postulated

The maxillary molar endodontic access opening: A microscope-based approach

PubMed Central

Mamoun, John Sami

2016-01-01

This article reviews the basic clinical techniques of performing a maxillary molar endodontic access opening, starting from the initial access opening into the pulp chamber, to the point where a size #10 file has been advanced to the apices of all three or four (or more) canals. The article explains how the use of the dental surgical operating microscope or microscope-level loupes magnification of ×6–8 or greater, combined with head-mounted or coaxial illumination, improve the ability of a dentist to identify microscopic root canal orifices, which facilitates the efficient creation of conservative access openings with adequate straight-line access in maxillary molars. Magnified photos illustrate various microscopic anatomical structures or landmarks of the initial access opening. Techniques are explored for implementing an access opening for teeth with vital versus necrotic pulpal tissues. The article also explores the use of piezoelectric or ultrasonic instruments for revealing root canal orifices and for removing pulp stones or calcified pulpal tissue inside the pulp chamber. PMID:27403069

34 CFR 263.3 - What definitions apply to the Professional Development program?

Code of Federal Regulations, 2013 CFR

2013-07-01

... load; and (3) Is not employed for more than 20 hours a week. Good standing means a cumulative grade point average of at least 2.0 on a 4.0 grade point scale in which failing grades are computed as part of... improve performance, (2) Access to research materials and information on teaching and learning, (3...

34 CFR 263.3 - What definitions apply to the Professional Development program?

Code of Federal Regulations, 2014 CFR

2014-07-01

... load; and (3) Is not employed for more than 20 hours a week. Good standing means a cumulative grade point average of at least 2.0 on a 4.0 grade point scale in which failing grades are computed as part of... improve performance, (2) Access to research materials and information on teaching and learning, (3...

Developmental Changes in the Access of Referential and Associative Information by Pictures and Words. Research Bulletin #9.

ERIC Educational Resources Information Center

Marschark, Marc; Carroll, Elizabeth

Three experiments examined referential and associative linkages in memory as a function of stimulus and response material formats. Second grade, sixth grade, and university students were the subjects. In Experiment 1, subjects pointed to either the picture or printed name of a stimulus corresponding to the name or picture, respectively, pointed to…

Is the GUI approach to Computer Development (For Example, Mac, and Windows Technology) a Threat to Computer Users Who Are Blind?

ERIC Educational Resources Information Center

Melrose, S.; And Others

1995-01-01

In this point/counterpoint feature, S. Melrose contends that complex graphical user interfaces (GUIs) threaten the independence and equal employment of individuals with blindness. D. Wakefield then points out that access to the Windows software program for blind computer users is extremely unpredictable, and J. Gill describes a major European…

75 FR 8423 - Self-Regulatory Organizations; NASDAQ OMX BX, Inc.; Notice of Filing of Proposed Rule Change To...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-24

... below $1. For these securities, BX currently charges members accessing liquidity a fee equal to 0.1% (10 basis points) of the total transaction cost and provides no credit to members providing liquidity. Under... transaction cost, and members providing liquidity will be provided a credit equal to 0.25% (25 basis points...