Local Data Communication Research Articles

The reliability evaluation of local computer networks using markov model of multiple heterogeneous groups of switches

At present, in all areas of life, the rapid development of information technology, which needs high-quality and fast exchange of information, needs data networks. The technical parameters of these networks must be studied accurately enough to design and develop new local computer networks. The task of investigating the reliable operation of these network parameters is the most urgent in the field of information technology. Therefore, common topologies of local computer networks and reliability models of recoverable systems are considered in the article. The Formulas for calculation of complex reliability indicators of the considered topology are given. The corresponding example is shown. For this, the Markov service model, that is, the description of a mass service operation using a Markov process with a discrete set of states, was used. This paper describes results that can improve the hardware reliability of local data communication networks in the design and modernization of existing technical systems.

Implementation of a weather station to monitor agricultural crops

Abstract Various studies on local crop monitoring are presented in the literature, however there is insufficient research on low-cost IoT weather stations that can obtain weather information over a long period of time. To overcome the difficulties described above, this paper proposes the development of an IoT weather station for low-cost, sustainable and multi-functional agricultural crop monitoring. The objective of the work is to develop a local weather observation device for agricultural crops, to set up a server for storing and providing meteorological information and to perform an analysis of the acquired weather data. The weather station architecture developed and proposed in this project consists of four main blocks: sensor and controller module, power module, local data storage module and data communication module (gateway).

Hardware Decoding Accelerator of (73, 37, 13) QR Code for Power Line Carrier in UPIoT

The proposal of the ubiquitous power Internet of Things (UPIoT) has increased the demand for communication coverage and data collection of smart grid; the quantity and quality of communication networks are facing greater challenges. This brief applies (73, 37, 13) quadratic residue (QR) codes to power line carrier technology to improve the quality of local data communication in UPIoT. In order to improve the decoding performance of the QR codes, an induction method for the error pattern is proposed, which can divide the originally coupled error pattern into six parts and reuse the same module for decoding. This method greatly reduces the resource requirements, so that (73, 37, 13) QR code can be implemented on FPGA hardware. Notably, the hardware architecture is a modular framework, which can fit into an FPGA with different sizes. As an example (73, 37, 13), QR code is implemented on Intel Arria10 FPGA; the experimental result shows that the maximum decoding frequency of this architecture is 21.7 M Hz, which achieves 4121x speedup compared to CPU. Moreover, the proposed architecture benefits from high flexibility, such as modular design and decoding framework in the form of the pipeline which can be seen as an alternative scheme for decoding long‐length QR codes.

Analysis, Deployment and Integration of Platforms for Fog Computing

In IoT applications, data capture in a sensor network can generate a large flow of information between the nodes and the cloud, affecting response times and device complexity but, above all, increasing costs. Fog computing refers to the use of pre-processing tools to improve local data management and communication with the cloud. This work presents an analysis of the features that platforms implementing fog computing solutions should have. Additionally, an experimental work integrating two specific platforms used for controlling devices in a sensor network, processing the generated data, and communicating with the cloud is presented.

D2D-Enabled Data Sharing for Distributed Machine Learning at Wireless Network Edge

Mobile edge learning is an emerging technique that enables distributed edge devices to collaborate in training shared machine learning models by exploiting their local data samples and communication and computation resources. To deal with the straggler dilemma issue faced in this technique, this paper proposes a new device to device enabled data sharing approach, in which different edge devices share their data samples among each other over communication links, in order to properly adjust their computation loads for increasing the training speed. Under this setup, we optimize the radio resource allocation for both data sharing and distributed training, with the objective of minimizing the total training delay under fixed numbers of local and global iterations. Numerical results show that the proposed data sharing design significantly reduces the training delay, and also enhances the training accuracy when the data samples are non independent and identically distributed among edge devices.

Voltage Quality Improvement in Low Voltage Distribution Networks Using Reactive Power Capability of Single-Phase PV Inverters

The rapid growth of residential rooftop photovoltaic (PV) systems may cause significant power quality problems, such as severe voltage fluctuation and unbalance which can restrict further PV integrations to the network. In this paper, the potential capability of residential PV inverters is investigated to develop a distributed reactive power compensation scheme for voltage regulation in three-phase four-wire unbalanced low voltage distribution networks (LVDNs). For this purpose, an effective method is proposed by means of single-phase PV inverters arbitrarily connected among different phases. The aims are improving voltage profile along the feeder and reducing the voltage unbalances. The PV inverters are connected in such a way that they form distributed delta and wye configurations to compensate the negative and zero sequence components of voltage, respectively and to regulate voltage within the allowed limits as well. The proposed consensus-based algorithm considers each PV system as a smart agent and updates its reactive power control setting based on only local measurements and data communications with neighboring agents. The effectiveness of the proposed strategy in terms of voltage regulation and unbalance and energy losses is shown through detailed simulations over a 24-hr period on a three-phase four-wire unbalanced LVDN with realistic data.

What drones inherit from their ancestors

Any specific technology derives attributes from the generic technologies of which it is an instance. A drone is a flying computer. It is dependent on local data communications from its onboard sensors and to its onboard effectors, and on telecommunications links over which it receives data-feeds and command-feeds from terrestrial and perhaps airborne sources and from satellites. A drone acts on the world, and is therefore a robot. The remote pilots, and the operators of drone facilities such as cameras, depend on high-tech tools that interpret data that display transmitted, enhanced and generated image and video, and that enable the composition of commands. So drone operators are already cyborgs. Many drones carry cameras and are used for surveillance. Computing, data communications, robotics, cyborgisation and surveillance offer power and possibilities, but with them come disbenefits and risks. Critical literatures exist in relation to all of those areas. An inspection of those literatures should provide insights into the limitations of drones, and the impacts and implications arising from their use.

General formulation of shift and delta operator based 2-D VLSI filter structures without global broadcast and incorporation of the symmetry

Having local data communication (without global broadcast of signals) among the elements is important in very large scale integration (VLSI) designs. Recently, 2-D systolic digital filter architectures were presented which eliminated the global broadcast of the input and output signals. In this paper a generalized formulation is presented that allows the derivation of various new 2-D VLSI filter structures, without global broadcast, using different 1-D filter sub-blocks and different interconnecting frameworks. The 1-D sub-blocks in z-domain are represented by general digital two-pair networks which consist of direct-form or lattice-type FIR filters in one of the frequency variables. Then, by applying the sub-blocks in various frameworks, 2-D structures realizing different transfer functions are easily obtained. As delta discrete-time operator based 1-D and 2-D digital filters (in $$\gamma $$ -domain) were shown to offer better numerical accuracy and lower coefficient sensitivity in narrow-band filter designs when compared to the traditional shift-operator formulation we have covered both the conventional z-domain filters as well as delta discrete-time operator based filters. Structures realizing general 2-D IIR (both z- and $$\gamma $$ -domains) and FIR transfer functions (z-domain only) are presented. As symmetry in the frequency response reduces the complexity of the design, IIR transfer functions with separable denominators, and transfer functions with quadrantal magnitude symmetry are also presented. The separable denominator frameworks are needed for quadrantal symmetry structures to guarantee BIBO stability and thus presented for both the operators. Some limitations of having exact symmetry with separable 1-D denominator factors are also discussed.

Pervasive multimedia guidance system for special needs passengers on public transport

This article presents a practical case of a pervasive multimedia guidance system for public transport passengers. In order to provide useful information to passengers, the system is capable of operating and adapting spontaneously to the different parts of a public transport network, using local data communication technologies. The multimedia data provided by the system are highly accessible, and adapt to the passengers' preferences, and are consequently suitable for special needs passengers. To this end, a paradigm of pervasive computing has been applied.

P51 Tuberculosis outcome following pre-treatment assessment for directly observed or self-administered therapy: still room for improvement?

Setting and MethodsLondon has high rates and large numbers of TB notifications. Treatment completion is generally <85% (the figure recommended by the WHO to achieve effective control). NICE TB guidelines...

VLSI architecture for quadtree-based fractal image coding

A VLSI architecture for flexible-size fractal image coding is proposed. The main features of this architecture are that it is capable of performing fractal image coding based on quadtree partitioning without the external memory for the fixed domain pool and uses only local data communication. Since large domain blocks consist of small domain blocks, the calculations of distortion for all kinds of domain block are performed using only the domain pool, which is extracted from the smallest range blocks of the neighbouring processors. This architecture has a fast comparison module which can compute the distortions between a range block and the eight isometric transformations of domain blocks by one full rotation around the centre.

Analysis of a bulk queue with N-policy multiple vacations and setup times

In this paper a M X / G( a, b)/1 queueing system with N-policy, multiple vacations and setup time is considered. After finishing a service, if the queue length is less than “ a”, the server leaves for a vacation of random length. When he returns, if the queue length is less than “ N” ( N≥ b), he leaves for another vacation and so on, until he finally finds at least “ N” customers waiting for service. After a vacation, if he finds more than “ N” customers in the system, he requires a setup time R to start the service. After the setup time he starts the service with a batch of “ b” customers. After a service, if the number of waiting customers is ξ ( ξ≥ a) then he serves a batch of min( ξ, b) customers, where b≥ a. Server vacation models are useful for the systems in which server wants to utilize his idle time for different purposes. Application of vacation models can be found in production systems, designing local area networks and data communication systems. This paper is concentrated on a vacation system with setup times. In practical situations, the setup time corresponds to the preparatory work of the server before starting the service. We derive the system size distribution and expected length of idle and busy period of a M X / G( a, b)/1 queueing system with N-policy, multiple vacations and setup time. After finishing a service, if the queue length is less than “ a”, the server leaves for a vacation of random length. When he returns, if the queue length is less than “ N” ( N≥ b), he leaves for another vacation and so on, until he finally finds at least “ N” customers waiting for service. After a vacation, if he finds more than “ N” customers in the system, he requires a setup time R to start the service. After the setup time he starts the service with a batch of “ b” customers. After a service, if the number of waiting customers is ξ ( ξ≥ a) then he serves a batch of min( ξ, b) customers, where b≥ a. A cost model for the queueing system is discussed. The numerical solution for a particular case of the model is also presented.

File and workload allocation design for distributed database on a two-level local multi-access computer network

This paper presents an analytical model to allocate files and workload simultaneously among heterogeneous servers that operate distributed databases on a two-level local multi-access computer network. The allocation problem is presented in the form of a non-linear integer programming model. The model incorporates both local processing and data communication overhead. The problem is NP-complete and thus a heuristic is developed. To illustrate its suitability, the heuristic is compared with an exhaustive enumeration method for small problems and with a genetic algorithm for large problems. Computational results imply that the heuristic provide effective database designs.

Design and performance evaluation of a new medium access control protocol for local wireless data communications

This paper proposes a new medium access control protocol for wireless data communications in local area, called the reservation-based multiple access with variable frame length (RMAV). We design RMAV under the consideration that the population of wireless terminals and the system load frequently change and are almost unpredictable in wireless data communications. RMAV is based on the slot reservation scheme and adopts a frame structure with variable length. The frame length increases as the number of active terminals and/or the system load increases. We evaluate the performance of RMAV by analysis and computer simulation. Due to its adaptability to traffic patterns, RMAV offers short delay in light load conditions and high throughput in heavy load conditions.

New parallel to computer project in Japan dedicated to computational physics

Brief report is made of a new project in Japan for construction of a parallel computer dedicated to lattice QCD and other problems of computational physics. This project is formed by a collaboration of lattice gauge theorists, physicists of other disciplines and computer scientists. The basic design is currently being worked out with a tentative design target of at least 300 GFlops for theoretical peak performance for 64 bit arithmetic and 48 GBytes of main memory with an interconnecting network suited to local data communication and a distributed disk system.

Cellular array processor CAP and applications

The general-purpose, highly parallel, cellular array processor (CAP) we developed features multiple-instruction stream, multiple-data stream (MIMD) processing and image display. Processor elements can number in several hundreds. The present system uses 256 processors. Each processor element consists of a general-purpose microprocessor, memory, and a special VLSI chip that performs parallel-processing-specific functions such as processor communication and synchronization. The VLSI has two 2M byte/s independent common bus interfaces for data broadcating and six 15M bit/s serial communication ports for local data communication. The chip also can process image data in real time for multiple processors. Use of the communication interfaces enables a variety of processor networks to be configured. One CAP application has been computer graphics, in which ray tracing is used to generate quality images.

A class of SIMD machines simulated by systolic arrays

In this paper we introduce a new subclass of single instruction steam/multiple data stream (SIMD) machines, referred to as a simple SIMD, then consider an implementation of a class of simple SIMD parallel algorithms onto systolic arrays, which have been considered as one candidate for VLSI-based cellular computers. The class of simple SIMD algorithms is so large that it includes many conventional SIMD algorithms, such as sorting, image processing, and graph algorithms. We develop several time-efficient algorithms for the simulations of simple SIMD machines, which have global data communications, by systolic arrays with only local data communications. The systolic simulation theorems enable us to use many conventional SIMD algorithms on the systolic arrays with little loss of time efficiency.

Establishment communication systems

In the sixties and early seventies, major activities in networking were focused on private and public data networks using either circuit and packet-switching technology or integrating both switching methods into a single network. In this time frame, manufacturers of main frames defined and implemented network architectures, ISO started work on the reference model of the Open-System Interconnect Architecture, and CCITT recommended the X-series of interfaces. Local-area communication networks (LAN's) represent a comparatively new field of activity which can be viewed as an extension to data networks for making high-speed packet-switching services available to the in-house domain. Currently, much research and development work is being pursued in this field, both at universities and in industry. The term local refers to communication on the users' premises, i.e., within a building or among a cluster of buildings. Local data and voice communication are not new. A typical example of a system widely used today for local data communication between hosts and display terminals is a star configuration where the terminals are attached to control units tightly coupled to a processor via I/O channels. The necessary terminal control functions are provided in the control unit and shared among a set of terminals. The most widely used local communication system is the Private Automatic Branch Exchange (PABX). Most PABX's installed today are optimised for real-time voice, and use analog technology.

Why a ring?

In a world increasingly populated with Ethernets and Ethernet-like nets there nevertheless continues to be a strong interest in rings of active repeaters for local data communication. This paper explores some of the engineering problems involved in designing a ring that has no central control. It then compares one ring design with the Ethernet on several different operational and subtle technical points of design, maintainability, and future prospects. On each of these points the ring possesses important or interesting advantages. At the same time, the most commonly cited advantage of a ring, “deterministic access time,” is shown to be illusory. The paper concludes that the data communication ring is a sound idea that will prove its value on operational rather than theoretical issues.

A High-Speed Fiber Optic Data Bus for Local Data Communications

Over the past decade, the volume of data compiled in industrial, military, and scientific databases has increased to enormous proportions. This increase has led to the development of new techniques for economically transporting information locally at high data rates. Leading among these techniques is the serial asynchronous multiterminal time-division multiplexed data bus. This paper describes a 100 Mbit/s fiber optic data bus system for connecting 16 terminals separated by up to 2 km. The system was developed as part of a NASA database management system for archiving and retrieval of satellite data. The NASA application will be briefly introduced followed by discussions on the high-speed data bus architecture, bus access protocols, system implementation, and error rate performance.