Journal articles: 'Relayed communication systems'

1

Hwang, F. K., and D. Shi. "Optimal relayed mobile communication systems." IEEE Transactions on Reliability 38, no. 4 (1989): 457–59. http://dx.doi.org/10.1109/24.46463.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Karagiannidis, G. K., T. A. Tsiftsis, and H. G. Sandalidis. "Outage probability of relayed free space optical communication systems." Electronics Letters 42, no. 17 (2006): 994. http://dx.doi.org/10.1049/el:20061443.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Aggarwal, Mona, Parul Garg, and Parul Puri. "Exact Capacity of Amplify-and-Forward Relayed Optical Wireless Communication Systems." IEEE Photonics Technology Letters 27, no. 8 (April 15, 2015): 903–6. http://dx.doi.org/10.1109/lpt.2015.2399953.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Aggarwal, Mona, Parul Garg, and Parul Puri. "Ergodic Capacity of SIM-Based DF Relayed Optical Wireless Communication Systems." IEEE Photonics Technology Letters 27, no. 10 (May 15, 2015): 1104–7. http://dx.doi.org/10.1109/lpt.2015.2407897.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Jiang, Xu, Zhilu Wu, Zhendong Yin, Wei Yang, and Zhutian Yang. "Trajectory and Communication Design for UAV-Relayed Wireless Networks." IEEE Wireless Communications Letters 8, no. 6 (December 2019): 1600–1603. http://dx.doi.org/10.1109/lwc.2019.2930968.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Aggarwal, Mona, Parul Garg, and Parul Puri. "Exact MGF-Based Performance Analysis of Dual-Hop AF-Relayed Optical Wireless Communication Systems." Journal of Lightwave Technology 33, no. 9 (May 1, 2015): 1913–19. http://dx.doi.org/10.1109/jlt.2015.2395425.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Besada, Juan A., David Carramiñana, Luca Bergesio, Ivan Campaña, and Ana M. Bernardos. "Modelling and Simulation of Collaborative Surveillance for Unmanned Traffic Management." Sensors 22, no. 4 (February 15, 2022): 1498. http://dx.doi.org/10.3390/s22041498.

Full text

Abstract:

Unmanned traffic management (UTM) systems rely on collaborative position reporting to track unmanned aerial system (UAS) operations over wide unsurveilled (with counter-UAS systems) areas. Many different technologies, such as Remote-ID, ADS-B, FLARM, or MLAT might be used for this purpose, in addition to the direct exploitation of C2 telemetry, relayed though cellular networks. This paper provides an overview of the most used collaborative sensors and surveillance systems in this context, analyzing their main technical parameters and performance effects. In addition, this paper proposes an abstracted general statistical simulation model covering message encoding, network capacity and access, sensors coverage and distribution, message transmission and decoding. Making use of this abstracted model, this paper proposes a particularized set of simulation models for ADS-B, FLARM and Remote-Id; it is thus useful to test their potential integration in UTM systems. Finally, a comparative analysis, based on simulation, of these systems, is performed. It is shown that the most relevant effects are those related with quantification and the potential saturation of the communication channels leading to collisions and delays.

APA, Harvard, Vancouver, ISO, and other styles

8

Peppas, Kostas P., Argyris N. Stassinakis, Hector E. Nistazakis, and George S. Tombras. "Capacity Analysis of Dual Amplify-and-Forward Relayed Free-Space Optical Communication Systems Over Turbulence Channels With Pointing Errors." Journal of Optical Communications and Networking 5, no. 9 (August 23, 2013): 1032. http://dx.doi.org/10.1364/jocn.5.001032.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Wang, Yifeng, Junwei Zou, and Kai Zhang. "Deep-Learning-Aided RF Fingerprinting for NFC RelayAttack Detection." Electronics 12, no. 3 (January 21, 2023): 559. http://dx.doi.org/10.3390/electronics12030559.

Full text

Abstract:

Near field communication (NFC) has been a widely used radiofrequency identification (RFID) technology, credited to its convenience and security features. However, the transmitted signals can be easily eavesdropped or relayed in an open wireless channel. One of the challenges is relay attack, where an attacker simply relays the signal and bypasses encryption or other means in the application layer. Prior works on relay attack countermeasures have focused on distance-bounding protocols or ambient-based solutions. This paper focuses on ISO/IEC 14443-A and proposes an NFC relay detection method based on RF fingerprinting of transmitted wireless signals in the physical layer. To this end, we first designed and implemented two realizations of NFC relay attacks, wired and wireless relays, and built an SDR-based testbed. We collected the normal and relayed signals of four NFC tags, and the answer to request type A (ATQA) segments were selected for RF fingerprinting. The created dataset comprised 66,366 samples, with four tags’ normal and wired relayed signals and the wireless relayed signals. The dataset was then fed into a deep CNN for training. Finally, our experiment results showed that the method effectively distinguished normal and relayed signals with a high accuracy of 99%, confirming that RF fingerprinting can be a promising countermeasure to NFC relay attacks.

APA, Harvard, Vancouver, ISO, and other styles

10

Yelamarthi, Kumar, Raghudeep Kannavara, and Sanjay Boddhu. "A Perceptual Computing based Gesture Controlled Quadcopter for Visual Tracking and Transportation." International Journal of Monitoring and Surveillance Technologies Research 3, no. 2 (April 2015): 57–67. http://dx.doi.org/10.4018/ijmstr.2015040104.

Full text

Abstract:

One of the fundamental challenges faced by an inexperienced user in portable unmanned aerial vehicle (UAV) such as quadcopters is flight control, often leading to crashes. Addressing this challenge, and leveraging upon the technological advancement in perceptual computing and computer vision, this research presents a modular system that allows for hand gesture based flight control of UAV, alongside a transport mechanism for portable objects. In addition to ascertain smooth flight control by avoiding obstacles in navigation path, real-time video feedback is relayed from the UAV to user, thus allowing him/her to take appropriate actions. This paper presents the design implementation by discussing the various sub-systems involved, inter system communication, and field tests to ascertain operation. As presented from testing results, the proposed system provides efficient communication between the subsystems for smooth flight control, while allowing for safe transport of portable objects.

APA, Harvard, Vancouver, ISO, and other styles

11

Androutsos, Nistazakis, Khalid, Muhammad, and Tombras. "Serial DF Relayed FSO Links over Mixture Gamma Turbulence Channels and Nonzero Boresight Spatial Jitter." Computation 7, no. 3 (July 5, 2019): 34. http://dx.doi.org/10.3390/computation7030034.

Full text

Abstract:

Over the past few years, terrestrial free space optical (FSO) communication systems have demonstrated increasing research and commercial interest. However, due the signal’s propagation path, the operation of FSO links depends strongly on atmospheric conditions and related phenomena. One such significant phenomenon is the scintillation caused by atmospheric turbulence effects; in order to address the significant performance degradation that this causes, several statistical models have been proposed. Here, turbulence-induced fading of the received optical signal is investigated through the recently presented mixture Gamma distribution, which accurately describes the irradiance fluctuations at the receiver’s input of the FSO link. Additionally, at the same time, it significantly reduces the mathematical complexity of the expressions used for the description of composite channels with turbulence along with nonzero boresight pointing error-induced fading. In order to counterbalance the performance mitigation due to these effects, serial decode-and-forward relays are employed, and the performance of the system is estimated through derived mathematical expressions.

APA, Harvard, Vancouver, ISO, and other styles

12

Burford, Benjamin P., and Bruce H. Robison. "Bioluminescent backlighting illuminates the complex visual signals of a social squid in the deep sea." Proceedings of the National Academy of Sciences 117, no. 15 (March 23, 2020): 8524–31. http://dx.doi.org/10.1073/pnas.1920875117.

Full text

Abstract:

Visual signals rapidly relay information, facilitating behaviors and ecological interactions that shape ecosystems. However, most known signaling systems can be restricted by low light levels—a pervasive condition in the deep ocean, the largest inhabitable space on the planet. Resident visually cued animals have therefore been hypothesized to have simple signals with limited information-carrying capacity. We used cameras mounted on remotely operated vehicles to study the behavior of the Humboldt squid, Dosidicus gigas, in its natural deep-sea habitat. We show that specific pigmentation patterns from its diverse repertoire are selectively displayed during foraging and in social scenarios, and we investigate how these behaviors may be used syntactically for communication. We additionally identify the probable mechanism by which D. gigas, and related squids, illuminate these patterns to create visual signals that can be readily perceived in the deep, dark ocean. Numerous small subcutaneous (s.c.) photophores (bioluminescent organs) embedded throughout the muscle tissue make the entire body glow, thereby backlighting the pigmentation patterns. Equipped with a mechanism by which complex information can be rapidly relayed through a visual pathway under low-light conditions, our data suggest that the visual signals displayed by D. gigas could share design features with advanced forms of animal communication. Visual signaling by deep-living cephalopods will likely be critical in understanding how, and how much, information can be shared in one of the planet’s most challenging environments for visual communication.

APA, Harvard, Vancouver, ISO, and other styles

13

Filatov, Vladimir I., Vitaly A. Julego, Valery U. Balakirev, and Sergey S. Ushakov. "DEVELOPMENT OF PROPOSALS FOR SELECTING AN ENSEMBLE OF BROADBAND SIGNALS SATELLITE COMMUNICATION SYSTEMS WITH MULTI-STATION ACCESS AND CODE DIVISION OF CHANNALS." T-Comm 15, no. 4 (2021): 13–20. http://dx.doi.org/10.36724/2072-8735-2021-15-4-13-20.

Full text

Abstract:

When designing satellite communication lines and calculating service areas, any unfavorable combinations of signal propagation conditions are taken into account, which, during operation of the repeater, leads to a significant underestimation of the calculated signal level in comparison with the actually provided one. Under these conditions, control of the compliance of the declared characteristics with the real level of the power flux density created by the satellite repeater at the earth’s surface in order to ensure electromagnetic compatibility is the most priority task. When conducting radio monitoring of satellite communication lines using active diagnostic methods, it is necessary to rationally determine the parameters of diagnostic signals so that they meet the conflicting requirements for their confident reception after being relayed by a satellite without disrupting (reducing the capacity) of the functioning of satellite communication lines. Mathematical modeling of the retransmission path of diagnostic signals in the multi-station repeater mode, taking into account the relative spatial location of the satellite, the service area and the radio monitoring station, has been carried out. The model takes into account most of the known factors and features of the propagation of radio signals in satellite communication lines in relation to various statistical phenomena in the atmosphere (refraction, signal depolarization), as well as the instability of the position of the satellite in orbit and the associated variability of the boundaries of the coverage area. As a result of the simulation, it was concluded that under conditions of a priori uncertainty about the polarization parameters used on board the monitored satellite of the antennas, there is a fundamental possibility of active diagnostics of the repeater shafts without weakening the diagnostic signal due to polarization mismatch.

APA, Harvard, Vancouver, ISO, and other styles

14

Briganti, Michael, Olivia A. Wackowski, Cristine D. Delnevo, Leanne Brown, Shirin E. Hastings, Binu Singh, and Michael B. Steinberg. "Content Analysis of Electronic Nicotine Delivery System Publications in Core Clinical Journals from 2012 to 2018." International Journal of Environmental Research and Public Health 17, no. 7 (March 25, 2020): 2201. http://dx.doi.org/10.3390/ijerph17072201.

Full text

Abstract:

There is no consensus if electronic nicotine delivery systems (ENDS) should be used to reduce harm among the smoking population. Physicians, who represent a trusted source of health communication, are exposed to a range of often conflicting ENDS information and this information may be relayed to patients looking to quit smoking. Previous studies have examined ENDS content of various sources of media but there is a lack of knowledge about ENDS content in medical journals. We analyzed 421 ENDS publications printed between 2012 and 2018 from PubMed’s Core Clinical Journal list. Publications were analyzed based on publication type, journal type, study design, geographic focus, theme, terminology, outcomes, and positive/negative statements. The number of ENDS publications grew since 2012, and peaked in 2015. Across all years, negative statements about ENDS outnumbered positive statements, though this difference decreased over time. Over time, negative statements about “toxins and carcinogens” were made less frequently, while negative statements about “gateway effects” and “youth appeal” became more prevalent. UK journals had fewer negative statements relative to US journals. Only 12.6% of publications included guidance for healthcare professionals about ENDS. As published ENDS topics change over time, physicians’ communications with patients may be impacted.

APA, Harvard, Vancouver, ISO, and other styles

15

Stephan, Thompson, Ananthnarayan Rajappa, K. S. Sendhil Kumar, Shivang Gupta, Achyut Shankar, and V. Vijayakumar. "Modified fuzzy-based greedy routing protocol for VANETs." Journal of Intelligent & Fuzzy Systems 39, no. 6 (December 4, 2020): 8357–64. http://dx.doi.org/10.3233/jifs-189154.

Full text

Abstract:

Vehicular Ad Hoc Networks (VANETs) is the most growing research area in wireless communication and has been gaining significant attention over recent years due to its role in designing intelligent transportation systems. Wireless multi-hop forwarding in VANETs is challenging since the data has to be relayed as soon as possible through the intermediate vehicles from the source to destination. This paper proposes a modified fuzzy-based greedy routing protocol (MFGR) which is an enhanced version of fuzzy logic-based greedy routing protocol (FLGR). Our proposed protocol applies fuzzy logic for the selection of the next greedy forwarder to forward the data reliably towards the destination. Five parameters, namely distance, direction, speed, position, and trust have been used to evaluate the node’s stability using fuzzy logic. The simulation results demonstrate that the proposed MFGR scheme can achieve the best performance in terms of the highest packet delivery ratio (PDR) and minimizes the average number of hops among all protocols.

APA, Harvard, Vancouver, ISO, and other styles

16

Ovcharenko, Konstsntin, Igor Eremeev, Konstantin Sazonov, Sergej Semenjuk, and Artjom Abakumov. "Differential Ranging Method of Locating Satellite Communication System Earth Stations using Repeater on an Unmanned Aerial Vehicle." SPIIRAS Proceedings 18, no. 1 (December 1, 2018): 176–201. http://dx.doi.org/10.15622/sp.18.1.176-201.

Full text

Abstract:

The article presents the differential ranging method of locating modern earth stations with narrow radiation patterns. Earth station position data is proposed to be calculated using maximum-likelihood procedure system solution from three differential equations using one of numerical methods. In this case supplementary assessment parameter of location, calculated by measuring a mutual signal delay of an earth station, relayed through a spacecraft on geostationary orbit and a mobile repeater on the unmanned aerial vehicle, can improve the accuracy of coordinate estimation earth station. For the developed method the analytical expressions of potential accuracy of calculation of coordinates of the earth station on the basis of the Cramer–Rao lower bound are developed. To measure the positioning accuracy of located emitters it is suggested to use the errors ellipsoid corresponding to the provision of a source of a radio emission in space. The analysis of standard routes of the movement of a repeater on the unmanned aerial vehicle is carried out and the conclusion is drawn that the best accuracy and the shortest route simultaneously are achieved, if the unmanned aerial vehicle follows a circular trajectory along the control area. Calculation of potential accuracy of positioning of the terrestrial station for the area of 50 by 50 km is executed.It is shown that the error of the estimates, received as a result of statistical tests, doesn’t surpass the size of a big half shaft of the error ellipsoid calculated with application of analytical expressions. The application of the developed method is possible in the implementation of the software of electronic control systems to counteract illegitimate use of frequency resource of space vehicles-satellite repeaters communication system.

APA, Harvard, Vancouver, ISO, and other styles

17

Patil, Siddhant S., Shruti K. Patil, Ishwari S. Chankeshwara, Hrishikesh S. Rapatwar, and Prof Vidya V. Waykule. "Speech Emotion Recognition System Using Recurrent Neural Network in Deep Learning." International Journal for Research in Applied Science and Engineering Technology 10, no. 3 (March 31, 2022): 2332–36. http://dx.doi.org/10.22214/ijraset.2022.41112.

Full text

Abstract:

Abstract: In today's world, machine learning and deep learning together are enabling around 80% of the human interactions through the sheer ubiquity of the solutions provided by this domain. But one of the problems with the existing world is most of the people are not able to understand the actual emotional meaning and occurrence behind a person's speech. For instance, people having problem like Catatonia, etc. are not able to express themselves clearly or some industries which are considering some marketing strategy according to the customer mood, etc. can use this method. So, to bridge this gap between the people, it is important to develop a system that can assist them and then predict their emotional speech. This paper reviews the different approaches adopted to reduce the barrier of emotional communication which are already in existence and what methodology they used while doing so. In this context, we also present an approach of using the Recurrent Neural Network which is a part of Deep learning algorithms. The whole process of automated systems which continuously learn, adapt, and improve without much instruction is really fascinating. Our primary goal is to create a robust communication system through technologies that enable machines to respond correctly and reliably to human voices and provide useful and valuable services accordingly. In this review, an extensive report is made on the various approaches available for speech emotion recognition that has been done till now. All the model's and accuracy aspects are taken into consideration and are relayed according to it. Keywords: Deep Learning, Recurrent Neural Networks, Emotion Recognition, Speech Recognition, SER, RNN, Catatonia.

APA, Harvard, Vancouver, ISO, and other styles

18

Lamarche, Alain, John Ion, Peter Rubec, A. A. LaVoi, and J. K. Winner. "Field Evaluation of a Wireless Electronic Shoreline Cleanup Support System." International Oil Spill Conference Proceedings 1999, no. 1 (March 1, 1999): 859–61. http://dx.doi.org/10.7901/2169-3358-1999-1-859.

Full text

Abstract:

ABSTRACT A prototype system was designed and assembled to electronically support all the steps involved in the cleanup phase of an oil spill response, from field data acquisition to decision making at a command post. The system included satellite communication, wireless Local Area Networks (LANs), Geographical Information Systems (GIS), and computerized Shoreline Cleanup Assessment Team (SCAT) support software. Field data entry was done using a penpad linked to a wearable computer, including (1) creation of electronic shoreline oiling summary diagrams with the help of a GIS; (2) completion of electronic SCAT forms; (3) exact positioning of oil patches and other spatial information with a differential Global Positioning System (DGPS); and (4) recording of images with a video camera. Information from the field was transmitted through a wireless LAN to a portable computer, which relayed the data via satellite communication to a central facility where information was integrated and analyzed for decision making. The system was evaluated during a number of field trials with personnel from the Bureau of Emergencies Response (state of Florida), normally involved in oil spill response. The evaluation demonstrated that (1) a stand-alone system, including differential GPS capability, was optimal to support SCAT activities in the field; (2) the setup and operation of a wireless LAN was both cumbersome and not worth the improvement in peiformance (reduced transfer time), particularly due to the necessity of deploying unwieldy directional antennas; (3) a major limitation was that the wearable computer's display was not visible under bright sunlight; (4) communication by wireless LAN and satellite network proved feasible, but too difficult to do routinely; (5) the use of computerized software tools in combination with detailed base maps (digital orthoquads) proved to be a huge improvement over the use of pen and paper; (6) the use of an all-electronic environment substantially shortened the length of time necessary to produce decision maps.

APA, Harvard, Vancouver, ISO, and other styles

19

Rawat, Rahul. "IoT Based Surveillance System Using DNN Model." International Journal for Research in Applied Science and Engineering Technology 9, no. 12 (December 31, 2021): 35–41. http://dx.doi.org/10.22214/ijraset.2021.39148.

Full text

Abstract:

Abstract: Localization, Visibility, Proximity, Detection, Recognition has always been a challenge for surveillance system. These challenges can be felt in the industries where surveillance systems are used like armed forces, technical-agriculture and other such fields. Most of the Smart system available are just for the surveillance of Human intervention but there is a need for a system which can be used for animals as well because with the outburst of human population and symbiotic relationship with wild animals results in life loss and damage to agriculture. In this paper we are designing to overcome these above-mentioned challenges for human and animal-based surveillance system in real time application. The system setup is done on a Raspberry pi integrated with deep-learning models which performs the classification of objects on the frames, then the classified objects is given to a face detection model for further processing. The detected face is relayed to the back-end for feature mapping with the saved log files with containing features of familiar face IDs. Four models were tested for face detection out of which the DNN model performed the best giving an accuracy of 94.88%.The system is also able to send alerts to the admin if any threat is detected with the help of a communication module. Keywords: Deep learning, Raspberry Pi, OpenCV, Image Processing, YOLO, Face Recognition

APA, Harvard, Vancouver, ISO, and other styles

20

Yadav, Shubham, Yashas Bharadwaj, Arjun Hariharan, Amit Choraria, Atharv Tendolkar, and M. M. Manohara Pai. "Smart Aero-Spider: An adaptive and selective smart switching aerator system." Journal of Physics: Conference Series 2161, no. 1 (January 1, 2022): 012061. http://dx.doi.org/10.1088/1742-6596/2161/1/012061.

Full text

Abstract:

Abstract The recovery from the COVID-19 pandemic hit shows the emergence of increase in quality of life across various parts of the world. With this lifestyle change, people are looking towards high quality food. Fish being a major source of protein, the industry producing fish from aquaculture is booming. The proposed smart aerator system provides an integrated array of underwater systems for selective aeration of the water body. The smart system ensures targeted aeration to guarantee optimal levels of dissolved oxygen at all times. This is beneficial for perfect survival, growth, and reproduction of fishes. The strategically placed spider aerators are turned on when readings from the dissolved oxygen level at the location is below the optimum range of values. The air blower system consists of an intelligent switching system to activate the right aerator based on the requirement. The sensor data is relayed to the cloud with a wireless communication module. This data can be used for useful insights and all-round monitoring of the water body. The respective aerators have IR sensor to detect movement alongside on-board LEDs to indicate functioning status. Overall, this ensures maximum accelerated growth of healthy fishes. Thus, the solution aims at efficiently boosting the ability of the aquaculture industry to meet the ever-growing demand of consumers.

APA, Harvard, Vancouver, ISO, and other styles

21

S, Nagarajan. "Secure Communication in Relay Selection based on Cognitive Radio Systems." SIJ Transactions on Computer Networks & Communication Engineering 05, no. 06 (December 29, 2017): 01–05. http://dx.doi.org/10.9756/sijcnce/v5i6/05010170101.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Vélez, Alejandro, Da Yeon Ryoo, and Bruce A. Carlson. "Sensory Specializations of Mormyrid Fish Are Associated with Species Differences in Electric Signal Localization Behavior." Brain, Behavior and Evolution 92, no. 3-4 (2018): 125–41. http://dx.doi.org/10.1159/000496493.

Full text

Abstract:

The ability to localize communication signals plays a fundamental role in social interactions. For signal localization to take place, the sensory system of the receiver must extract information about distance and direction to the sender from physical characteristics of the signal. In many sensory systems, information from multiple peripheral receptors must be integrated by central sensory pathways to determine the sender location. Here, we asked whether evolutionary divergence in the electrosensory and visual systems of mormyrid fish is associated with signal localization behavior. In mormyrids, differences in the distribution of electroreceptors on the surface of the skin are associated with differences in the midbrain exterolateral nucleus (EL). Species with electroreceptors clustered in three rosettes on both sides of the head have a small and undifferentiated EL. In contrast, EL is enlarged and subdivided into anterior (ELa) and posterior (ELp) regions in species that have electroreceptors broadly distributed throughout the body. Interestingly, species with EL and clustered electroreceptors also have larger visual systems and higher visual acuity than species with ELa/ELp and broadly distributed electroreceptors. Species with broadly distributed electroreceptors and ELa/ELp approached a simulated conspecific by following the curved electric field lines generated by the electrosensory stimulus. In contrast, a species with small EL and clustered electroreceptors, but an enlarged visual system, followed shorter and straighter paths to the stimulus source. In the central electrosensory system, evoked field potentials in response to stimuli delivered from the left versus the right differed more in EL than in ELa/ELp. Our results suggest that signal localization behavior is associated with differences in sensory specializations. We propose that the distribution of electroreceptors on the body affects the ability of individuals to align parallel to electric field lines and maintain such alignment while approaching the signal source. The spatial resolution of sensory information relayed from the periphery to the midbrain in species with clustered electroreceptors may allow for gross, but not fine, processing of sender location. Furthermore, visual information may play an important role in localizing signaling individuals in species with small EL and clustered electroreceptors. In line with previous studies, we suggest that the physiological and behavioral differences associated with signal localization reflect adaptations to different habitats and social environments.

APA, Harvard, Vancouver, ISO, and other styles

23

Thompson, A. R. "Coordination Between the Radioastronomy Service and the Radiodetermination Satellite Service in the 1612 MHZ Band." International Astronomical Union Colloquium 112 (1991): 205–12. http://dx.doi.org/10.1017/s0252921100004024.

Full text

Abstract:

The Radiodetermination Satellite Service (RDSS) provides radiolocation and limited communication for users of aeronautical, marine and terrestrial vehicles. A system of the RDSS is being developed in the United States by the Geostar Corporation (Rothblatt, 1988). In this system signals from a control center are transmitted to transceivers on users’ vehicles through one of a series of two or three satellites spaced along the geostationary orbit, and responses are received through each of these satellites. If three satellites are used, locations of vehicles can be determined from the measured times of transmission from the control center to the user and back via different satellite paths. If two satellites are used the timing data must be supplemented by information such as altitude data from a terrain map, or an altimeter reading from the user’s vehicle, which can be encoded in the response transmitted back. Computation of the vehicle location is performed at the control center. The equipment at the vehicle can be relatively simple since its basic function is that of a transponder, and intervention by the vehicle operator is not necessarily required. However, provision can also be made for the inclusion of short coded messages from the vehicle, so the unit on the vehicle is usually referred to as a transceiver. The system is designed to meet the needs of various users; for example, trucking companies which must periodically monitor the locations of vehicles in a widely distributed fleet. Position information can be relayed to the company headquarters as well as to the vehicle operator. The role played by the central control computer in determining the locations requires that all vehicles using the service identify themselves by a transmitted code. Thus developers and operators of RDSS systems can lease their services to vehicle users.

APA, Harvard, Vancouver, ISO, and other styles

24

Sanguesa, Julio A., Fernando Naranjo, Vicente Torres-Sanz, Manuel Fogue, Piedad Garrido, and Francisco J. Martinez. "On the Study of Vehicle Density in Intelligent Transportation Systems." Mobile Information Systems 2016 (2016): 1–13. http://dx.doi.org/10.1155/2016/8320756.

Full text

Abstract:

Vehicular ad hoc networks (VANETs) are wireless communication networks which support cooperative driving among vehicles on the road. The specific characteristics of VANETs favor the development of attractive and challenging services and applications which rely on message exchanging among vehicles. These communication capabilities depend directly on the existence of nearby vehicles able to exchange information. Therefore, higher vehicle densities favor the communication among vehicles. However, vehicular communications are also strongly affected by the topology of the map (i.e., wireless signal could be attenuated due to the distance between the sender and receiver, and obstacles usually block signal transmission). In this paper, we study the influence of the roadmap topology and the number of vehicles when accounting for the vehicular communications capabilities, especially in urban scenarios. Additionally, we consider the use of two parameters: the SJ Ratio (SJR) and the Total Distance (TD), as the topology-related factors that better correlate with communications performance. Finally, we propose the use of a new density metric based on the number of vehicles, the complexity of the roadmap, and its maximum capacity. Hence, researchers will be able to accurately characterize the different urban scenarios and better validate their proposals related to cooperative Intelligent Transportation Systems based on vehicular communications.

APA, Harvard, Vancouver, ISO, and other styles

25

Latvakoski, Juhani, and Jouni Heikkinen. "A Trustworthy Communication Hub for Cyber-Physical Systems." Future Internet 11, no. 10 (October 8, 2019): 211. http://dx.doi.org/10.3390/fi11100211.

Full text

Abstract:

The motivation for this research arises from the challenges in the trustworthy communications related operation of cyber-physical systems (CPS), especially in the energy and mobility domains. The increasing amount of distributed energy resources (DERs) of prosumers and electric vehicles requires new ways for CPS communications to enable information exchanges for smart operation in peak consumption hours and balancing power levels in the energy grids in order to lower the energy cost. The huge number of mobile appliances and the related service providers do not serve properly the privacy of the owners, owing to the vertical silo type of operating model in industries. As the results of this research, we provide a trustworthy communication hub for CPS (CPS hub) for solving the challenges related to trustworthy communications between physical resources owned by different stakeholders. The CPS hub realizes the communication spaces concept, and enables combined trust and communications processes when dynamic resources owned by different stakeholders are exchanging information. The evaluations showed that the provided CPS hub enable information exchanges between distributed energy resources of different stakeholders, so that they can join the aggregation process for more flexible and efficient resource usage in energy markets. The CPS hub enable interaction between heterogeneous physical devices of multiple stakeholders to exchange information so that, for example, authorities can see the situation in the emergency area and, simultaneously, the policies of the owners can be taken into concern. Despite limited evaluation scenarios, it is shown that consideration of the ownership issues in the trustworthy communication for information exchanges between heterogeneous physical resources (devices) is possible and feasible. Several future research items, such as, for example, scalability; real-time and streams based operation; as well as consideration of the security, privacy, trust, and safety challenges, were detected. However, the evaluations showed that the constructed CPS hub contribute a set of very essential technical enablers for future smart CPS systems and create strong a basis for such future research towards a future smart society.

APA, Harvard, Vancouver, ISO, and other styles

26

Shell, Duane F., Christy A. Horn, and Mary K. Severs. "Computer-Based Compensatory Augmentative Communications Technology for Physically Disabled, Visually Impaired, and Speech Impaired Students." Journal of Special Education Technology 10, no. 1 (September 1989): 29–43. http://dx.doi.org/10.1177/016264348901000104.

Full text

Abstract:

Compensatory Augmentative Communications Technology is the use of computers and related technology to augment written or verbal communication. In this paper we describe augmentative writing systems for physically disabled and visually impaired students and augmentative communication systems for nonverbal speech impaired students. The components used in creating augmentative systems are detailed with specific examples of the systems used in the Educational Center for Disabled Students at the University of Nebraska-Lincoln. Issues in assessment, system selection, and training and system limitations are discussed.

APA, Harvard, Vancouver, ISO, and other styles

27

Yun, Pei-yan, Jin Guo, and Xiao-dong Wang. "360216 RESEARCH ON SAFETY-RELATED COMMUNICATION OF RAILWAY AUTOMATIC BLOCK BETWEEN RAILWAY STATIONS SYSTEM(Signal,Technical Session)." Proceedings of International Symposium on Seed-up and Service Technology for Railway and Maglev Systems : STECH 2009 (2009): _360216–1_—_360216–4_. http://dx.doi.org/10.1299/jsmestech.2009._360216-1_.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Siergiejczyk, Mirosław. "Availability of the Motorway Emergency Communications." Journal of Konbin 5, no. 2 (January 1, 2008): 291–306. http://dx.doi.org/10.2478/v10040-008-0053-3.

Full text

Abstract:

Availability of the Motorway Emergency Communications The paper presents issues related to the assessment of availability of one of the motorway telematics systems: the emergency communication system. The essence and tasks of transport telematic systems have been presented in a general outline. The architecture of the fibre optic emergency communication system and the tasks of particular subsystems have also been presented. Using the functional structure and the method of sending information through the system, a method for calculating the availability of the motorway emergency communication system was proposed.

APA, Harvard, Vancouver, ISO, and other styles

29

Paley, Michael J., Michael P. Linegang, and Rebecca M. Morley. "Using Communication Data to Assess Organizational and System Effectiveness in Future Combat Systems." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 46, no. 3 (September 2002): 290–94. http://dx.doi.org/10.1177/154193120204600316.

Full text

Abstract:

The interconnected nature of the Army's Future Combat System provides an opportunity to use communication analysis as a viable evaluation method of both organizational efficiency and system design. In the current investigation, communications during teamin-the-loop experimentation were collected and analyzed for both content and flow patterns. Results suggest that players did not fully utilize the functionality of a common operating picture (COP) and new technology insertion did not achieve the desired effect within the organization. Requests for information and updates were frequently related to information that could have been found on the COP. The communication patterns suggested that the experimental organization was very much hierarchical, with little horizontal communications. That is, despite the influx of new systems, traditional operations were employed. In this study, communication data were successfully employed to assess operational effectiveness and the quality of system design.

APA, Harvard, Vancouver, ISO, and other styles

30

Schmidt, Karsten, Marian Graumann, and Joachim Bobrich. "Rapid Mapping for German Federal Authorities." Abstracts of the ICA 1 (July 15, 2019): 1–2. http://dx.doi.org/10.5194/ica-abs-1-322-2019.

Full text

Abstract:

Abstract. The Federal Agency for Cartography and Geodesy (BKG) in Germany is a technical agency under the Federal Ministry of the Interior, Building and Community (BMI). The organization consists of three departments namely Geoinformation, Geodesy and a Business Operations/Support department. Each department has multiple units which carry out their own respective duty in their field of subject. Tasks related to providing and homogenizing spatial data are located inside the geoinformation department. The main focus lies here on uniting the data collected by the federal states to form different types of nationwide datasets. The geodesy department focusses on real time satellite navigation systems, very long baseline interferometry and geodetic reference systems.A recent development in the federal authorities has been the demand for quick maps and spatial data to support fast decision making processes. The BKG has established a complete workflow which allows for rapid data processing and the distribution to the respective customers. It is split into six sub processes with several branching options, processing and backpropagation steps. This allows for a systematic approach to covering the customer’s demand for spatial data and for the internal production chain. The workflow is backed up by a project management system, a quality management system and a production management system each covered in a handbook specially prepared to ensure consistency along the workflow.The workflow gets started by the customer posing their request either via the service center (SC) unit, via mail or phone or through the controlling institution as a decree or an executive order. The first contact is crucial as important information is being exchanged and a rough concept of the demand is shaped. Once the actual task has reached the BKG a ticket number and an internal processing identifier will be assigned by the SC and the resource manager (RM) respectively. These unique keys will be used for the communication with the customer and additionally utilized as a tool for the administrative actions being carried out in the background. This action involves querying the license status of the customer which in addition determines the maximum cost of the task and the authorization of the data being used. In parallel the task, now referred to as a ticket, is being implemented in the project management system. Certain additional information will be assigned to the ticket like the project manager (PM) and the project processor. Once this step has been completed the working directory for the ticket will be created by using a predefined folder structure. This structure is composed of a data, export, communications and documentation folder. Depending on the nature of the ticket various preconfigured templates are at hand and will be used to ensure uniformity of the final products. If needed further communication with the customer is carried out. Data research is the last step in this part of the workflow (see figure 1).The processing of the actual data makes up most of the workflow regarding time. Aspects like a uniform styleguide and quality controls by colleagues are performed alongside the work progress. If any non comforming aspect is found, the feedback is given directly to the person in charge of the ticket while also being mirrored in the project management system. Once the product is ready for deployment, final communication with the customer is executed. Additional changes stated by the customer can be implemented whereby an extra iteration of the quality process will be necessary. The data deployment is either carried out as a print product, a DVD, an OGC service or via a download option (see figure 2).The final steps of the workflow involve the report of delivery to the service center, the creation of the cost report and the closure of the ticket in the project management system. The cost report is created in a semi-automatic process from data stored in the project management system and combined with the material cost report. It is then send via e-mail to the service center which will carry out any necessary invoice collections. Furthermore the internal data folder structure is cleaned up and a screenshot is taken of the product to use it as a subsidiary product in the dedicated online gallery of created products. Finally the closing information is relayed to the service center and the ticket gets closed (see figure 3). This whole workflow can be executed within several hours, days or weeks, depending on the deadline imposed by the customer or the event. Actual rapid mapping activations are done by multiple people simultaneously working on different steps of the previously explained workflow. This allows for fast response times and the accomplishment of the activation in time.

APA, Harvard, Vancouver, ISO, and other styles

31

Lee, Gyeonghwan, Myeongju Lee, and Yoonhwan Sohn. "High-Performance Work Systems And Firm Performance: Moderating Effects Of Organizational Communication." Journal of Applied Business Research (JABR) 33, no. 5 (August 30, 2017): 951–62. http://dx.doi.org/10.19030/jabr.v33i5.10018.

Full text

Abstract:

This study examines the relationship between high-performance work systems (HPWS) and organizational performance and how the relationship differs by type of communication within organizations. Using data on publicly traded manufacturing firms in Korea from the Human Capital Corporate Panel survey, we find that HPWS are positively related to organizational performance, and importantly, this relationship varies by the level of vertical and horizontal communication. The positive effect of HPWS on organizational performance is more apparent when vertical and horizontal communications are relatively high. These results emphasize the role of internal communication as an important organizational context for the implementation of HPWS.

APA, Harvard, Vancouver, ISO, and other styles

32

Demiryürek, K. "Information systems and communication networks for agriculture and rural people." Agricultural Economics (Zemědělská ekonomika) 56, No. 5 (June 1, 2010): 209–14. http://dx.doi.org/10.17221/1/2010-agricecon.

Full text

Abstract:

This review paper presents the concepts, theories and literature review that are relevant to information systems and communication networks for agriculture and rural people. The usefulness of information systems and communication networks is discussed in order to identify the system components, their networks, the understanding of how successfully they work and how to improve their performances. The definitions of terms used in this paper, such as information, system, information system, agricultural information systems and communication networks are first presented and discussed. The rationale of the system theory and information system approach and analysis method for agricultural information systems are described and discussed. In addition, the findings of related previous studies are reviewed and summarized. Finally, general conclusions about agricultural information systems are emphasized and implications for further research areas are presented.

APA, Harvard, Vancouver, ISO, and other styles

33

Rastocny, Karol, and Maria Franekova. "Modelling in Development of Safety-Related Communication Systems." Communications - Scientific letters of the University of Zilina 10, no. 1 (March 31, 2008): 24–30. http://dx.doi.org/10.26552/com.c.2008.1.24-30.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Goldberg, Gary, and Roberta Brooks. "Premotor systems, language-related neurodynamics, and cetacean communication." Behavioral and Brain Sciences 21, no. 4 (August 1998): 517–18. http://dx.doi.org/10.1017/s0140525x98291266.

Full text

Abstract:

The frame/content theory of speech production is restricted to output mechanisms in the target article; we suggest that these ideas might best be viewed in the context of language production proceeding as a coordinated dynamical whole. The role of the medial premotor system in generating frames matches the important role it may play in the internally dependent timing of motor acts. The proposed coevolution of cortical architectonics and language production mechanisms suggests a significant divergence between primate and cetacean species corresponding to major differences in areal differentiation trends in cerebral cortex.

APA, Harvard, Vancouver, ISO, and other styles

35

Frank Cervone, H. "Effective communication for project success." OCLC Systems and Services: International digital library perspectives 30, no. 2 (May 6, 2014): 74–77. http://dx.doi.org/10.1108/oclc-02-2014-0014.

Full text

Abstract:

Purpose – The purpose of this review is to look at some of the common mistakes made related to communication within a project and how those mistakes can be avoided. Communication in projects is a critical factor in a project’s success. Many times, project teams forget some basic rules for communicating with their stakeholders. Design/methodology/approach – The approach of this paper is to provide a general overview of common themes in the project management literature related to communication within projects. Findings – While communication failures in projects are caused by many factors, the project team ultimately bears the burden for ensuring successful communication within a project. There are several common causes of communication failures. Thankfully, there are also some simple things that project teams can do to lessen the likelihood of miscommunication. Research limitations/implications – As this is a general overview, this article only explores the more commonly experienced issues related to project miscommunication. Originality/value – By observing some relatively easy to remember questions and concerns related to communication, a project team can be more effective in communicating with their project stakeholders. Effective communication will generally lead to better outcomes and, therefore, a higher likelihood for overall project success.

APA, Harvard, Vancouver, ISO, and other styles

36

Jiang, Wenyi, Ke Guan, Zhangdui Zhong, Bo Ai, Ruisi He, Binghao Chen, Yuanxuan Li, and Jia You. "Propagation and Wireless Channel Modeling Development on Wide-Sense Vehicle-to-X Communications." International Journal of Antennas and Propagation 2013 (2013): 1–11. http://dx.doi.org/10.1155/2013/981281.

Full text

Abstract:

The need for improving the safety and the efficiency of transportation systems has become of extreme importance. In this regard, the concept of vehicle-to-X (V2X) communication has been introduced with the purpose of providing wireless communication technology in vehicular networks. Not like the traditional views, the wide-sense V2X (WSV2X) communications in this paper are defined by including not only vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications but also train-to-X (T2X) communications constituted of train-to-train (T2T) and train-to-infrastructure (T2I) communications. All the information related to the wide-sense V2X channels, such as the standardization, scenarios, characters, and modeling philosophies, is organized and summarized to form the comprehensive understanding of the development of the WSV2X channels.

APA, Harvard, Vancouver, ISO, and other styles

37

Aas, I. H. Monrad, and Jonn Terje Geitung. "Teleradiology and picture archiving and communications systems: Changed pattern of communication between clinicians and radiologists." Journal of Telemedicine and Telecare 11, no. 1_suppl (July 2005): 20–22. http://dx.doi.org/10.1258/1357633054461589.

Full text

Abstract:

In a few years all radiology departments in Norwegian hospitals will have a picture archiving and communications system (PACS). This depends on telecommunications with great capacity for transmitting radiology images. The new technology questions the need for daily meetings between radiologists and clinicians, ‘clinico-radiological conferences’. Qualitative interviews were performed with 23 resource persons experienced with problems related to PACS and teleradiology. The response rate was 91 %. In all, 29% answered that the clinico-radiological conferences could be abolished, 52% replied no and 19% replied both yes and no. The clinico-radiological conferences could be abolished for some clinical departments, but only after consultation between radiology and clinical departments. If the conferences are abolished, clinicians and radiologists may spend more time on treatment and interpretation, with a probable productivity gain.

APA, Harvard, Vancouver, ISO, and other styles

38

DURRESI, Mimoza. "Ad-hoc wireless sensor communications for health monitoring systems." Ingenious 2, no. 1 (2022): 7–14. http://dx.doi.org/10.58944/rycc2468.

Full text

Abstract:

The Covid 19 challenge, the increased aging population, and the modern way of living are increasing the need for health monitoring communications services. Healthcare monitoring is a very important research field of study. This is related in finding new, more efficient ways in health data communications with three main quality of service requirements: low delay, high security, high quality data transmission. Considering these requirements and recent developments in domestical health monitoring services, it is important not only the equipment used for health monitoring sensing but also the communication protocol used to access the data center. In this paper we develop a new communication protocol for ad-hoc wireless network created by the sensors used for personal health monitoring systems installed in patient wrists. This is a hierarchical protocol where the sensors communicate through a virtual infrastructure that helps to collect the data from the personal health monitoring equipments in an efficient way even in the areas with no wireless infrastructure. The communication scheme ensures a hierarchy of nodes that gets translated to hierarchy of costs as only a few nodes need to have a larger processing power resulting in a lower battery consumption for most of the patients. The neighbourhood area is divided into virtual cells where each cell is represented from one node center that holds the communication for all the surrounded nodes and forwards its information towards the next cell center found in the direction of the sink. As a result the information collected even in the fields without any wireless infrastructure might be carried towards the cells that are in a communication distance with the sink. The updated information data is forwarded toward the data centers to be analysed by the specialists. Taking in consideration that even in the urban areas the elderly population doesn’t have internet services, this ad-hoc communication protocol represents a good solution for health monitoring equipments. Moreover, the same communication protocol can be used for signaling life signs in war areas.

APA, Harvard, Vancouver, ISO, and other styles

39

Bornman, Juan, Kerstin Tönsing, and Ensa Johnson. "Model for Vocabulary Selection of Sensitive Topics: An Example from Pain-Related Vocabulary." Seminars in Speech and Language 38, no. 04 (September 2017): 276–85. http://dx.doi.org/10.1055/s-0037-1604275.

Full text

Abstract:

AbstractVocabulary selection for graphic symbol-based augmentative and alternative communication systems is important to enable persons with significant communication difficulties to express a variety of communication functions to indicate needs and wants, to develop social closeness, and to fulfill social etiquette. For persons who experience pain, abuse, bullying, or neglect, it is essential to be able to communicate about sensitive issues. However, published core vocabulary lists allow limited scope for communicating about sensitive topics, due mainly to the techniques employed to determine such lists (e.g., observations or recording of communication patterns of peers with typical development during fun-based or daily activities). This article is based on the outcome of a study of children's pain-related vocabulary. Based on the study, we propose a model for selecting vocabulary on sensitive topics. The model consists of four phases: (1) using hypothetical scenarios; (2) considering different perspectives that may affect vocabulary selection; (3) involving direct stakeholders, and (4) customizing vocabulary.

APA, Harvard, Vancouver, ISO, and other styles

40

Siergiejczyk, Mirosław. "Reliability Model of Motorway Emergency Communication System." Solid State Phenomena 210 (October 2013): 122–29. http://dx.doi.org/10.4028/www.scientific.net/ssp.210.122.

Full text

Abstract:

The paper presents some issues related to reliability model of a motorway telematics systems, in particular emergency communication system. Optical system architecture was presented and functions of the various subsystems, too. Analyzing the functional structure and method for transmitting information in a highway emergency communications system a method to calculate the reliability of the system was proposed. To assess the reliability of the emergency communication system, as a system repairable, availability index was also proposed.

APA, Harvard, Vancouver, ISO, and other styles

41

Goodman, John M., John A. Klobuchar, and Haim Solcher. "Foreword: Ionospheric effects on communication and related systems (IES)." Radio Science 23, no. 3 (May 1988): 209. http://dx.doi.org/10.1029/rs023i003p00209.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Goodman, John M., John A. Klobuchar, and Haim Soicher. "Foreword: Ionospheric effects on communication and related systems (IES)." Radio Science 23, no. 4 (July 1988): 481. http://dx.doi.org/10.1029/rs023i004p00481.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Gray, Alistair Howard. "Medicines-related communication systems and the new NICE guidance." Prescriber 26, no. 21 (November 3, 2015): 24–26. http://dx.doi.org/10.1002/psb.1408.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Carvajal-Rodríguez, Jorge, Christian Tipantuña, Felipe Leonel Grijalva Arévalo, and Luis Felipe Urquiza Aguiar. "Descripción general de comunicaciones habilitadas por UAV en escenarios de emergencia posterior a un desastre." Revista de Investigación en Tecnologías de la Información 10, no. 21 (September 2022): 132–39. http://dx.doi.org/10.36825/riti.10.21.012.

Full text

Abstract:

Maintaining communications and providing services to users is crucial after a natural disaster due to the damage to traditional communications networks. Emergency networks using UAVs solve this problem due to their rapid deployment. This article presents an overview of the challenges and solutions related to the feasibility of emergency communication systems in different scenarios, path planning, and positioning. Besides, It describes the technologies to realize the core and implemented networks associated with UAVs.

APA, Harvard, Vancouver, ISO, and other styles

45

Jit Singh, Mandeep Singh, Wan Syahrum Wan Saleh, Amer T. Abed, and Muhammad Ashraf Fauzi. "A Review on Massive MIMO Antennas for 5G Communication Systems on Challenges and Limitations." Jurnal Kejuruteraan 35, no. 1 (January 30, 2023): 95–103. http://dx.doi.org/10.17576/jkukm-2023-35(1)-09.

Full text

Abstract:

High data rate transfers, high-definition streaming, high-speed internet, and the expanding of the infrastructure such as the ultra-broadband communication systems in wireless communication have become a demand to be considered in improving quality of service and increase the capacity supporting gigabytes bitrate. Massive Multiple-Input Multiple-Output (MIMO) systems technology is evolving from MIMO systems and becoming a high demand for fifth-generation (5G) communication systems and keep expanding further. In the near future, massive MIMO systems could be the main wireless systems of communications technology and can be considered as a key technology to the system in daily lives. The arrangement of the huge number of antenna elements at the base station (BS) for uplink and downlink to support the MIMO systems in increasing its capacity is called a Massive MIMO system, which refers to the vast provisioning of antenna elements at base stations over the number of the single antenna of user equipment. Massive MIMO depends on spatial multiplexing and diversity gain in serving users with simple processing signal of uplink and downlink at the BS. There are challenges in massive MIMO system even though it contains numerous number of antennas, such as channel estimation need to be accurate, precoding at the BS, and signal detection which is related to the first two items. On the other hand, in supporting wideband cellular communication systems and enabling low latency communications and multi-gigabit data rates, the Millimeter-wave (mmWave) technology has been utilized. Also, it is widely influenced the potential of the fifth-generation (5G) New Radio (NR) standard. This study was specifically review and compare on a few designs and methodologies on massive MIMO antenna communication systems. There are three limitations of those antennas were identified to be used for future improvement and to be proposed in designing the massive MIMO antenna systems. A few suggestions to improve the weaknesses and to overcome the challenges have been proposed for future considerations.

APA, Harvard, Vancouver, ISO, and other styles

46

C. A. D, Pahalson, and Nanchen Nimyel Caleb. "5G Wireless Communications for Future Internet of Things: The Need for Free-Space Optical/Visible Light Communication Technology." International Journal of Computer Science and Mobile Computing 8, no. 12 (December 30, 2019): 124–32. http://dx.doi.org/10.47760/ijcsmc.2019.v08i12.001.

Full text

Abstract:

IoT networks have some important characteristics. Some key requirements of the IoT are low device cost, low deployment cost, high energy efficiency, high security and privacy, and support for a large number of devices. The LED-based OWC systems have all the great features required to support the IoT. The key technologies currently used for IoT connectivity are Zigbee, Bluetooth Low Energy (BLE), and WiFi. ZigBee is a low-cost, low-power, wireless mesh network standard that has been widely used for IoT applications. The Internet of Things (IoT) based on the tactile internet will also be an essential part of the 5G communication systems. Accordingly, 5G wireless networks will face numerous challenges in supporting the extensive verities of heterogeneous networks and in satisfying the mentioned service-quality-related parameters. Optical wireless communication (OWC), along with many other wireless technologies, is a promising candidate for serving the demands of 5G communication systems.

APA, Harvard, Vancouver, ISO, and other styles

47

Cecílio, José, Pedro M. Ferreira, and António Casimiro. "Evaluation of LoRa Technology in Flooding Prevention Scenarios." Sensors 20, no. 14 (July 20, 2020): 4034. http://dx.doi.org/10.3390/s20144034.

Full text

Abstract:

Global climate change originates frequent floods that may cause severe damage, justifying the need for real-time remote monitoring and alerting systems. Several works deal with LoRa (Long Range) communications over land and in the presence of obstacles, but little is known about LoRa communication reliability over water, as it may happen in real flooding scenarios. One aspect that is known to influence the communication quality is the height at which nodes are placed. However, its impact in water environments is unknown. This is an important aspect that may influence the location of sensor nodes and the network topology. To fill this gap, we conducted several experiments using a real LoRa deployment to evaluate several features related to data communication. We considered two deployment scenarios corresponding to countryside and estuary environments. The nodes were placed at low heights, communicating, respectively, over the ground and over the water. Measurements for packet loss, received signal strength indicator (RSSI), signal-to-noise ratio (SNR) and round-trip time (RTT) were collected during a period of several weeks. Results for both scenarios are presented and compared in this paper. One important conclusion is that the communication distance and reliability are significantly affected by tides when the communication is done over the water and nodes are placed at low heights. Based on the RTT measurements and on the characteristics of the hardware, we also derive a battery lifetime estimation model that may be helpful for the definition of an adequate maintenance plan.

APA, Harvard, Vancouver, ISO, and other styles

48

Zhang, Haojie, Di Ren, and Fanghua Jiang. "A Beam Search-Based Channel Allocation Method for Interference Mitigation of NGSO Satellites with Multi-Beam Antennas." Aerospace 9, no. 4 (March 23, 2022): 177. http://dx.doi.org/10.3390/aerospace9040177.

Full text

Abstract:

In the past few years, non-geostationary orbit (NGSO) satellite communication constellations have regained popularity due to their conspicuous advantages. Nevertheless, with more NGSO satellites getting involved in communications, the spectrum resources should become much more scarce. Multi-beam high throughput satellite and spectrum sharing are two major techniques in communication design. The two techniques can significantly mitigate interference and highly augment the capacity of the communication system. Thus, they are commonly used in satellite communication systems nowadays. With a massive number of NGSO satellites comprising the communication system and moving in their orbits, interference scenarios are pretty complex. In this article, the relationship between the level of interference and the beam distance is deduced. Moreover, for beams with different tilting angles, the different off-axis angles may correspond to the same beam distance, which is directly related to the interference level. Through the interference analysis, we propose a channel allocation method that uses a beam search algorithm to optimize the channel allocation problem and achieves outstanding time efficiency. The performance of the proposed method is validated by a coexisting scenario of the geostationary orbit and NGSO satellite communication systems. The results show that the level of interference can be largely mitigated, and the capacity of communication systems is significantly augmented.

APA, Harvard, Vancouver, ISO, and other styles

49

Naqvi, Aqeel, and Sungjoon Lim. "Review of Recent Phased Arrays for Millimeter-Wave Wireless Communication." Sensors 18, no. 10 (September 21, 2018): 3194. http://dx.doi.org/10.3390/s18103194.

Full text

Abstract:

Owing to the rapid growth in wireless data traffic, millimeter-wave (mm-wave) communications have shown tremendous promise and are considered an attractive technique in fifth-generation (5G) wireless communication systems. However, to design robust communication systems, it is important to understand the channel dynamics with respect to space and time at these frequencies. Millimeter-wave signals are highly susceptible to blocking, and they have communication limitations owing to their poor signal attenuation compared with microwave signals. Therefore, by employing highly directional antennas, co-channel interference to or from other systems can be alleviated using line-of-sight (LOS) propagation. Because of the ability to shape, switch, or scan the propagating beam, phased arrays play an important role in advanced wireless communication systems. Beam-switching, beam-scanning, and multibeam arrays can be realized at mm-wave frequencies using analog or digital system architectures. This review article presents state-of-the-art phased arrays for mm-wave mobile terminals (MSs) and base stations (BSs), with an emphasis on beamforming arrays. We also discuss challenges and strategies used to address unfavorable path loss and blockage issues related to mm-wave applications, which sets future directions.

APA, Harvard, Vancouver, ISO, and other styles

50

Xiao, Zheng Rong, Li Yun Zhang, Jun Liao, and Bin Feng Yan. "Coexistence Studies between Mobile Communication Systems and Broadcasting Systems." Applied Mechanics and Materials 303-306 (February 2013): 2022–26. http://dx.doi.org/10.4028/www.scientific.net/amm.303-306.2022.

Full text

Abstract:

With the rapid development of mobile internet, more and more frequency band will be needed to meet the requirement of high data speed. The system coexistence between mobile system and broadcast system is studied, including the scenarios, models, simulation results, related analysis, and finally the solution to resolve the coexistence is given. In urban, an additional 37dB isolation between broadcast system and mobile base station should been satisfied. And an additional 15.7dB is needed between mobile base station and broadcast receiver.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Relayed communication systems'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles