Uninterrupted Communication Research Articles

Communicating between the hearing and the deaf. in search for innovative solutions

Democratization of social life in Poland after political transformation of 1989 meant that people with disabilities, including the deaf began to participate in social life actively and demand the ability to use full rights of citizenship. Active presence in the public space requires a constant, uninterrupted communication. In order to improve communication it is necessary to teach the hearing ways to communicate they use to encourage the deaf and the hearing to acquire these skills. First of all, the so-called linguistic-sign system (SJM), which uses visual-spatial channel to communicate, is used for communication. Polish Sign Language (PJM) became an innovation in search for better communication between the hearing and the deaf since the first years of the 21st century. Dissemination of the Polish Sign Language (PJM) and teaching this language to the hearing gives more opportunities to communicate the deaf with the hearing. Skills of using Polish sign language are essential in everyday public life interactions in institutions of public administration and health services or places of culture.

VERTICAL HANDOVER DECISION MANAGEMENT ON THE BASIS OF SEVERAL CRITERIA FOR LVQNN WITH UBIQUITOUS WIRELESS NETWORKS

Vertical handover decision management is an essential to keep the seamless ubiquitous heterogeneous wireless networks since each access network has different operations in the next generation. In this paper, WCDMA, LTE and WLAN are cooperated in the architecture of mobile IP regional registration (MIP-RR). We propose the Learning Vector Quantization Neural Networks (LVQNNs) approach in order to maintain uninterrupted communication that depends on received signal strength indicator, data rate requirement, monetary cost of service and mobile terminal device speed metrics are considered as multi-criteria to initial handover. Furthermore, the multi-criteria are dynamic to influence for real-time and non-real time services in different networks and the users select the optimal target network which is the highest handover factor score in order to balance against the network condition and user preference. To ensure the Always Best Connected (ABC) demands, the simulation results illustrate that our proposed algorithm provided outperform the performance in term of unnecessary handover, the call dropping probability, data packet delay and network utilization compared with conventional method as fuzzy logic and neural network based machine learning.

MIMO H∞ control of three-axis ship-mounted mobile antenna systems

ABSTRACTThe need for on-line information in any environment has led to the development of mobile satellite communication terminals. These high data-rate terminals require inertial antenna pointing error tolerance within fractions of a degree. However, the base motion of the antenna platform in mobile applications complicates this pointing problem and must be accounted for. Gimbaled motorised pedestals are used to eliminate the effect of disturbance and maintain uninterrupted communication. In this paper, a three-axis ship-mounted antenna on a pedestal gimbal system is studied. Based on the derived dynamic model of the antenna pedestal multi input-multi output PID and H∞ linear controllers are designed to stabilise the antenna to keep its orientation unaltered towards the satellite while the sea waves disturb the antenna. Simulation results are presented to show the stabilisation performance of the system with the synthesised controllers. It is shown through performance comparison and analysis that the proposed H∞ control structure is preferable over PID controlled system in terms of system stability and the disturbance rejection.

Towards seamless inter-technology handovers in vehicular IPv6 communications

Network mobility plays an important role in communications when using different access networks while maintaining application sessions. This is the case of vehicular networks used by the emerging Cooperative Intelligent Transport System (C-ITS), where vehicles are constantly moving, changing their access network. Standardization bodies like IETF, and particular proposals in the literature, have already defined mobility mechanisms by using widely used Internet technologies. The usefulness of these mechanisms in vehicular networks is clear when using IPv6, however, its performance suffer from the high mobility of nodes, the fluctuating performance of communication technologies, and the need for a decision mechanism to choose a proper attachment point among the available access networks on roads. For this reason, here we propose an instantiation of the ISO/ETSI reference architecture for vehicular cooperative systems, by deploying a real vehicular network based on IPv6, as well as a mobility service provided by Network Mobility Basic Support (NEMO) and the Multiple Care of Addresses Registration (MCoA) extension. This mobility solution is embedded into a framework that integrates the IEEE 802.21 technology, which provides a greater control over the handover process. The resulting architecture not only provides a seamless handover but also supports the decision making when searching for the most suitable target network. Our experiments reveal that our combined NEMO/MCoA/802.21 system within a vehicular communication stack is able to provide uninterrupted communications during handovers with a dramatic reduction in the time needed by this process.

Robust Adaptive Coordination Controller for a Spacecraft Equipped with a Robotic Manipulator

Free-flying robotic spacecraft play a significant role in the space industry today. Unlike ground-based robots, the manipulator motion in a space robot can cause undesirable disturbances to the spacecraft platform, causing its attitude to change, potentially disrupting communication and solar energy collection processes as a result. Thus, coordinated control of both the spacecraft attitude and the manipulator motion become essential for successful space operations. Though past research has developed dynamic models for spacecraft manipulators, the contribution of reaction wheels to the angular momentum of the entire system needs further consideration. This paper reformulates the dynamic equations of a free-flying space robot by taking the aspect of reaction wheels into account. A diagonalization method is introduced to decouple the highly nonlinear multi-input/multi-output system model. A novel adaptive variable structure control method is then applied to implement a robust coordination controller for the space robot subjected to system uncertainties. Simulations are carried out on a spacecraft model with a 3-degree-of-freedom manipulator mounted on it to demonstrate the robustness of the proposed approach. Comparisons with sliding mode control show that the new controller results in faster settling times, which leads to maintaining uninterrupted communication links and efficient solar energy harvesting.

34 Time-motion Study of Attending Physician Teaching Activities and Interruptions at a Large Academic Emergency Department

As crowding in the emergency department (ED) becomes more widespread, there is concern that physicians may be pushed to increase clinical productivity at the expense of other activities, including teaching. Time and motion methodology applied to the ED setting is recent and has focused on understanding length of stay, communication patterns, and interruptions. We performed an observational, time-motion study in the ED of Grady Memorial Hospital using electronic data capture in order to study attending physician work flow patterns. We aimed to categorize physician tasks for the purpose of gaining a deeper understanding of work flow in order to improve efficiency. Our statistical analysis evaluated several teaching-focused questions including whether teaching led to less time spent in other areas (eg, electronic medical record (EMR), walking, and communication). Additionally, we evaluated whether interruptions affect time spent teaching. In this prospective, observational cohort study, trained research assistants shadowed physicians and recorded tasks in sub-minute intervals in three clinical zones of an urban level I trauma center: triage and supervision in a low-acuity area; a high-acuity medical area; and a trauma area. Quetech Workstudy + tablet-based software was used for data collection with the ability to record tasks of short duration (< 10 seconds). Task categories were prospectively defined and included direct patient care, EMR use, teaching, communication, walking, and waiting. Task details included interaction type, type of human contact, role of contacted staff, and patient identification. An interrater analysis was performed to ensure quality and consistency of data collected by six observers. A univariate regression analysis was used to determine the relationship between teaching and other activities. This research was funded by the Emory Medical Care Foundation. A total of 700 hours of observational data were collected for 52 faculty members, for a total of 62000 data points. A 1-minute increase in attending EMR resulted in a 0.85% decrease in the physician’s time spent teaching (p=0.02). Each additional minute of communication time was associated with a 2.38% increase in teaching time (p<0.0001). A 1-minute increase in uninterrupted communication time resulted in a 1.04% increase in teaching time (p<0.001), while a 1-minute increase in interrupted communication time corresponded to a 3.83% increase in teaching time (p<0.0001). Each minute spent walking resulted in a 4.34% increase in teaching time (p=0.01). As expected, there is a tradeoff between time spent using EMR and teaching. As communication time increased, we expected an increase in teaching time since these communication types included teaching. We were surprised, however, that interrupted communication time was associated with a greater increase in teaching time compared to uninterrupted communication. It is possible that more fragmented work flow may lead to more teaching opportunities. The positive association between walking and teaching time is surprising, leading to the hypotheses that attending physicians who are more physically active during shifts also engage more in teaching, or that walking serves as a segue to a teaching moment. These results help us gain a better understanding of the ways in which teaching can be effectively incorporated into ED work flow.

Modelling and stabilization of a three-axis ship-mounted mobile antenna system

A mobile satellite communication antenna is a device installed on a moving carrier for mobile satellite communication. Gimballed motorized pedestals are used to eliminate the effect of disturbance and maintain uninterrupted communication when the carrier is moving. Mobile satellite communication antennas are becoming increasingly more popular due many advantages of mobile satellite communication. In this paper, a three-axis ship-mounted antenna on a pedestal gimbal system is studied. We study the problem with a different perspective and method from the previous work for two-axis antenna pedestals. The former studies treat the subsystems to be isolated and design controllers separately, which neglect the coupling effects in the dynamics of two or three-axis antenna pedestal gimbals. We treat three sub-systems as a whole and derive the dynamic model of the system using the Newton–Euler method. Based on the dynamic model, linear PI controllers are designed to stabilize the antenna to keep its orientation towards the satellite. The design objective of the control system is to direct the on-board antenna toward a satellite and to keep its orientation unaltered despite the effect of sea waves disturbing the antenna. Simulation results are presented to show the stabilization performance of the system with the synthesized controllers.

Anticipatory Networked Communications for Live Musical Interactions of Acoustic Instruments

Performing music over computer networks requires highly reliable infrastructures with respect to latency elimination, bandwidth availability and error alleviation. Hence, commonly available networks or large communication distance cannot effectively cope with real-time, high-fidelity and uninterrupted musical communications. An intuitive solution to this problem can be offered by employing mechanisms for musical prediction and anticipation which can help mitigate technical impediments. The idea is that knowing in advance the evolution of a music piece can offer effective reduction of communication latencies and data rates. Furthermore, musical anticipation can be used to eliminate errors owing to data loss in the network transmission path. We present the development of a software prototype that uses anticipatory processes to support networked music performance. The adopted methodology is inspired by computer accompaniment systems, in which a software agent follows the performance of a human musician in real-time, by synchronizing a pre-recorded musical accompaniment to the expressive nuances of live interpretation. The paper presents an overview of relevant research initiatives, the computational approach implemented for anticipatory networked performances and an experimental validation that demonstrates current progress and reveals constraints and challenges pending further investigation.

A Novel Link Reliable Multipath Routing Protocol for MANET

Mobile Ad Hoc networks (MANETs) are self configurable wherein mobile nodes communicate with each other via wireless links. Due to ever-changing topology, frequent link failure and lack of fixed infrastructure, it is difficult to develop and maintain an optimal route between source and destination nodes in MANET. In such a network, it is highly required to construct a link reliable route in order to provide an uninterrupted communication. This paper proposes an ant colony optimization (ACO) based link reliable (LR) ad hoc on demand multipath distance vector (AOMDV) routing (ACO-LR-AOMDV) which is inspired from swarm intelligence especially using collective behavior of natural ants. It establishes and maintains multiple routes between a pair of mobile nodes using simulated pheromone deposited by artificial ants. The optimal path is selected based on hop count and minimum value of the Path-Link Quality Estimator (P-LQE) which have been integrated into the pheromone computation of the path. The efficiency of the proposed protocol is examined using the network simulator NS2.34 and the experimental results show the better performance over the well-known multipath routing protocol AOMDV and ACO-AOMDV in terms of end-to-end delay, routing overhead and packet delivery ratio.

U-business: a taxonomy and growth strategies

U-business uses ubiquitous computing technologies to support uninterrupted communications in business transactions to gain competitive advantage. This study seeks to identify patterns underlying successful U-business growth. It follows four stages: 1 dimensions important for the study of U-business growth strategies were identified through examining past cases. Two dimensions were identified: nature of change Improvement vs. Innovation and implementation environment Physical vs. Virtual Value Chain. 2 These dimensions were then used to build a taxonomy of U-business types and a growth strategy type was defined as a transition from one of these types to another. 3 A focus group consisting of U-business and UbiComp experts was then used to validate these dimensions and generate hypotheses about successful strategies. 4 These strategies were then tested by using the transition strategies that Apple has used in its product offerings. These findings are used to provide guidelines about growth strategies for U-business companies.

Underground Communication: Radio Propagation Prediction for CBTC Data Communication Subsystem Design

The radio-based data communication subsystem (DCS) between trains and wayside is a key factor for safe and efficient operation of a communication-based train control (CBTC) system. The train control system is now able to provide efficient, flexible, and cost-effective operation by using cutting-edge information and communication technologies collectively referred to as CBTC. CBTC technology has become standardized, and its commercialization trend has witnessed a drastic growth in recent years [1], [2]. CBTC systems are able to ensure safety and promote railroad transportation capacity and operational flexibility through continuous bilateral communication between the wayside and the moving vehicle. The cited communication is established through the DCS based on wired and/or wireless media [3], [4]. The radio-based DCS is an integrated seamless Ethernet-Internet Protocol network that includes both wire-lined and wireless components. Providing adequate radio-frequency (RF) coverage in the operational frequency band, which is normally composed of the upper ultrahigh frequency (UHF)/lower superhigh frequency (SHF), throughout the service area is the foundation for delivering uninterrupted wireless communication and, as such, a design requirement for the DCS.

Energy-efficient stable routing using QoS monitoring agents in MANET

Abstract In mobile ad hoc network (MANET), the most important issue is to provide a stable and reliable route for the uninterrupted communication. In order to overcome these issues, in this paper, we propose a stable and energy-efficient routing technique. In the proposed method, quality of service (QoS) monitoring agents collect and calculate the link reliability metrics such as link expiration time (LET), probabilistic link reliable time (PLRT), link packet error rate (LPER) and link received signal strength (LRSS). In addition, residual battery power (RBP) is implemented to maintain the energy efficiency in the network. Finally, route selection probability (RSP) is calculated based on these estimated parameters using fuzzy logic. Simulation results show that the proposed routing technique improves the packet delivery ratio and reduces the energy consumption.

Performance improvement of color space based VLC modulation schemes under color and intensity variation

Color space based modulation (CSBM) schemes have the potential to replace conventional intensity based modulation in visible-light communication (VLC) systems. This study attempts to address three major issues of the CSBM scheme in VLC systems, which are (1) performance improvement of CSBM as compared to conventional intensity based modulation, (2) intensity control, and (3) adaption to color variation. We improve the bit error rate (BER) performance of the CSBM scheme by incorporating an error boundary decision method. We analyze our proposed scheme by varying color during communication and introduce a color lookup table in order to obtain a more accurate target color at the receiver. We evaluate the CSBM scheme when the transmitter sends and does not send the target color information, and we also consider the effect of channel coding on the system performance. The computer simulation results, assuming an additive white Gaussian noise (AWGN) channel, demonstrate an uninterrupted communication system under intensity and color variation.

WAP Based Seamless Roaming In Urban Environment with Wise Handoff Technique

This paper highlights the studies performed to arrive at a novel handoff scheme in achieving uninterrupted connectivity. Every wireless communication user prefers seamless mobility and uninterrupted communication. Achieving this scenario is quite challenging both technologically and economically. Few of the reasons are geographical and man made constraints. Dynamic changes in environment and ever changing geographical landscape also pose serious difficulties to engineers involved in design of wireless systems. The following schemes have been suggested in an effort to improve Q.o.S of wireless mobile communication scenarios.

Interference Mitigation between Ultra-Wideband Sensor Network and Other Legal Systems

Ultra-wideband impulse radio (UWB-IR) sensor network has intensive military and commercial applications. However, the interference between UWB and other existed networks should be casually investigated. In this paper, we consider interference mitigation in UWB sensors in the context of cognitive radio (CR). Firstly, we suggest a general state transition model to characterize the working states evolution of legal networks, also referred to as primary users (PU). Spectrum sensing, used to identify the state of PU, is formulated as detection of a corresponding state sequence. Maximum posterior probability (MAP) criterion is adopted to perform spectrum sensing. By exploring potential gain of state transitions, detection probability for nearby networks is improved significantly. Subsequently, based on the radius basis function neural network (RBF), we present a novel spectrum sculptor to design UWB waveforms. Attributed to the excellent reconfiguration of RBF, our scheme can produce UWB waveforms tracing available spectrums. The designed waveforms can entirely utilize multiple unoccupied bands to maintain uninterrupted communications. Also, sufficient spectral attenuation can be generated in specific bands to mitigate mutual interference between UWB sensors and other networks. Besides, orthogonal waveforms can be easily derived, which either improves transmission performance or provides a flexible accessing strategy for UWB sensors.

WAP Based Seamless Roaming In Urban Environment with Wise Handoff Technique

This paper highlights the studies performed to arrive at a novel handoff scheme in achieving uninterrupted connectivity. Every wireless communication user prefers seamless mobility and uninterrupted communication. Achieving this scenario is quite challenging both technologically and economically. Few of the reasons are geographical and man made constraints. Dynamic changes in environment and ever changing geographical landscape also pose serious difficulties to engineers involved in design of wireless systems. The following schemes have been suggested in an effort to improve Q.o.S of wireless mobile communication scenarios.

Cross-Layer Architecture for a Satellite–Wi-Fi Efficient Handover

To achieve fully mobile communications, considering different environments and modern service requirements, a multiple-segment architecture is the most suitable to guarantee service continuity with acceptable performance. Handover (HO) procedures can be invoked either out of necessity (if the current network connection is going off) or to improve performance (if different bandwidth or quality of service is required). In this scenario, to provide uninterrupted communication services, efficient intersegment HO capability must be implemented. The architecture considered includes a satellite segment and a number of Wi-Fi hot spots. A mobile node (MN) can switch from a segment to other exploiting services of mobile Internet protocol (MIP). This architecture introduces great flexibility and ensures capillary coverage; it also strongly affects Transmission Control Protocol (TCP)-based application performance. To efficiently face HO consequences, particularly when the TCP runs as a transport protocol, an innovative protocol architecture based on cross-layer (CL) exchange of information is proposed. Analyses of TCP dynamics during HOs and the performance improvement introduced with the proposed CL architecture, evaluated through the network simulator Ns-2, are presented.

Planning for disasters and responding to catastrophes: error of the third type in disaster policy and planning

This paper states that the public increasingly expects better public sector leadership before, during and after catastrophic disasters than it has seen in the past. The massive numbers of public, non-profit and private organisations involved in catastrophic disasters require extensive ability to have horizontal, as well as vertical, communication, coordination and decision-making capabilities. High performance in response to catastrophic disasters requires an ability to assess and adapt capacity rapidly, restore or enhance disrupted or inadequate communications, utilise uncharacteristically flexible decision making and expand coordination and trust of emergency response organisations. These requirements are superimposed on conventional bureaucratic systems that rely on relatively rigid plans, exact decision protocols and formal relationships that assume uninterrupted communications. Yet, policy makers and policy analysts frequently focus on certain aspects of disaster managements after a significant disaster and commit error of the third type. This paper suggests investing in building bottom-up community capacity in a networked environment.

Design and analysis of a fault tolerant hybrid mobile scheme

Mobile computing systems provide users with access to information regardless of their geographical location. In these systems, Mobile Support Stations (MSSs) play the role of providing reliable and uninterrupted communication and computing facilities to mobile hosts. The failure of a MSS can cause interruption of services provided by the mobile system. Two basic schemes for tolerating the failure of MSSs exist in the literature. The first scheme is based on the principle of checkpointing used in distributed systems. The second scheme is based on state information replication of mobile hosts in a number of secondary support stations. Depending on the replication scheme used, the second approach is further classified as a pessimistic or an optimistic technique. In this paper, we propose a hybrid scheme which combines the pessimistic and the optimistic replication schemes. In the proposed scheme, an attempt is made to strike a balance between the long delay caused by the pessimistic and the high memory requirements of the optimistic schemes. In order to find the best ratio between the number of pessimistic to the number of optimistic secondary stations in the proposed scheme, we used fuzzy logic. We also used simulation to compare the performance of the proposed scheme with those of the optimistic and the pessimistic schemes. Simulation results showed that the proposed scheme performs better than either schemes in terms of delay and memory requirements.

Free-space quantum key distribution with entangled photons

The authors report on a complete experimental implementation of a quantum key distribution protocol through a free-space link using polarization-entangled photon pairs from a compact parametric downconversion source. Over 10h of uninterrupted communication between sites 1.5km apart, they observe average key generation rates of 630∕s after error correction and privacy amplification. Their scheme requires no specific hardware channel for synchronization apart from a classical wireless link, and no explicit random number generator.