610,785 research outputs found

    Multi-service systems: an enabler of flexible 5G air-interface

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    Multi-service system is an enabler to flexibly support diverse communication requirements for the next generation wireless communications. In such a system, multiple types of services co-exist in one baseband system with each service having its optimal frame structure and low out of band emission (OoBE) waveforms operating on the service frequency band to reduce the inter-service-band-interference (ISvcBI). In this article, a framework for multi-service system is established and the challenges and possible solutions are studied. The multi-service system implementation in both time and frequency domain is discussed. Two representative subband filtered multicarrier (SFMC) waveforms: filtered orthogonal frequency division multiplexing (F-OFDM) and universal filtered multi-carrier (UFMC) are considered in this article. Specifically, the design methodology, criteria, orthogonality conditions and prospective application scenarios in the context of 5G are discussed. We consider both single-rate (SR) and multi-rate (MR) signal processing methods. Compared with the SR system, the MR system has significantly reduced computational complexity at the expense of performance loss due to inter-subband-interference (ISubBI) in MR systems. The ISvcBI and ISubBI in MR systems are investigated with proposed low-complexity interference cancelation algorithms to enable the multi-service operation in low interference level conditions

    Extended Data Management Facility (EDMF) Reference Manual/User\u27s Guide

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    An advanced data management system developed by the project on Computer Aids to Human Intellect sponsored by the Information Systems Program of ONR has been placed into regular service on the RCA SPECTRA 70/46G time-shared computer system at the Moore School of Electrical Engineering of the University of Pennsylvania. This system provides extensive facilities for information storage and retrieval, multi-level access control, and general problem solving. Incorporating a number of new concepts in the areas of file structure, data protection, and time-shared operating systems for large-scale computers, the new data management system represents a major portion of the work carried out over the past several years. The system allows file owners to specify various types of access not only to their files, but to records of information within those files as well. The generalized file structure incorporated in the system, and its associated storage and retrieval algorithms, permit the user to choose among a number of possible file structures, including the well-known inverted, multilist and index-sequential files. Such a choice of file structures in a single system has never before been available. The system also provides for the definition of problem solving procedures and allows user\u27s programs to request data management service during execution

    A Study on the improvement of national water supply system for improving water reliance

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    Thesis(Master) --KDI School:Master of Public Management,2020.The water supply system is a social infrastructure for the development of public welfare and industry, which has contributed to improving the quality of people's sanitation and economic growth. Korea's water supply service has grown rapidly with economic growth despite its short history of about 100 years. Today, safe tap water is available essentially everywhere in the country and, the quality of tap water is also comparable to that of developed countries. However, behind this growth there are various problems such as public water supply coverage rates and service imbalances in urban and rural areas, profit structures that cause chronic deficits, leakage and water supply service interruption due to aged facilities, and deep distrust of tap water. These problems remain a long-standing challenge. In addition, more systematic water management is required as the risk of water management from recent climate change is increasing while the people's expectations for water services are rising. The one of the fundamental causes of such problems is the waterworks’ structure which is directly operated by local governments, unlike other services, and water supply management system that is divided into multi-regional and local. South Korea has continued to manage water supply projects in the public sector at the national level to enhance the equity of water welfare services and balanced regional development. However, since many utilities, including K-water and 161 local governments, have been operating separate water supply systems under the control of two central ministries, they have produced various inefficiencies over the decades, including overlapping investments, reduced supply stability and an imbalance in water services. Fortunately, Korea's water supply service is entering a new phase as Framework Water Management Act was enacted in 2018 that led to the water management function being integrated into the Ministry of Environment. Accordingly, the government is pushing for the reorganization of the water management system, the adjustment of functions, and the establishment of new policies for the rational use of national water resources. I would like to analyze the problems of the Korean water supply system from various perspectives such as structure, process, human resource management and propose a direction for the improvement of the national water supply system and specific implementation measures in this study.1. Introduction 2. Necessity of improving the water supply system 3. Analysis of water supply system problems 4. Literature review 5. Findings and proposal 6. ConclusionmasterpublishedKOO, Sunghu

    Novel multiuser detection and multi-rate schemes for multi-carrier CDMA

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    A large variety of services is [sic] expected for wireless systems, in particular, high data rate services, such as wireless Internet access. Users with different data rates and quality of service (QoS) requirements must be accommodated. A suitable multiple access scheme is key to enabling wireless systems to support both the high data rate and the integrated multiple data rate transmissions with satisfactory performance and flexibility. A multi-carrier code division multiple access (MC-CDMA) scheme is a promising candidate for emerging broadband wireless systems. MC-CDMA is a hybrid of orthogonal frequency division multiplexing (OFDM) and code division multiple access (CDMA). The most salient feature of MC-CDMA is that the rate of transmission is not limited by the wireless channel\u27s frequency-selective fading effects caused by multipath propagation. In MC-CDMA, each chip of the desired user\u27s spreading code, multiplied by the current data bit, is modulated onto a separate subcarrier. Therefore, each subcarrier has a narrow bandwidth and undergoes frequency-flat fading. Two important issues for an MC-CDMA wireless system, multiuser detection and multi-rate access, are discussed in this dissertation. Several advanced receiver structures capable of suppressing multiuser interference in an uplink MC-CDMA system, operating in a frequency-selective fading channel, are studied in this dissertation. One receiver is based on a so-called multishot structure, in which the interference introduced by the asynchronous reception of different users is successfully suppressed by a receiver based on the minimum mean-square error (MMSE) criterion with a built-in de-biasing feature. Like many other multiuser schemes, this receiver is very sensitive to a delay estimation error. A blind adaptive two-stage decorrelating receiver based on the bootstrap algorithm is developed to combat severe performance degradation due to a delay estimation error. It is observed that in the presence of a delay estimation error the blind adaptive bootstrap receiver is more near-far resistant than the MMSE receiver. Furthermore, a differential bootstrap receiver is proposed to extend the limited operating range of the two-stage bootstrap receiver which suffers from a phase ambiguity problem. Another receiver is based on a partial sampling (PS) demodulation structure, which further reduces the sensitivity to unknown user delays in an uplink scenario. Using this partial sampling structure, it is no longer necessary to synchronize the receiver with the desired user. Following the partial sampling demodulator, a minimum mean-square error combining (MMSEC) detector is applied. The partial sampling MMSEC (PS-MMSEC) receiver is shown to have strong interference suppression and timing acquisition capabilities. The complexity of this receiver can be reduced significantly, with negligible performance loss, by choosing a suitable partial sampling rate and using a structure called reduced complexity PS-MMSEC (RPS-MMSEC). The adaptive implementation of these receivers yields a superior rate of convergence and symbol error rate performance in comparison to a conventional MMSEC receiver with known timing. All the above receiver structures are for a single-rate MC-CDMA. Three novel multi-rate access schemes for multi-rate MC-CDMA, fixed spreading length (FSL), coded FSL (CFSL) and variable spreading length (VSL), have been developed. These multi-rate access schemes enable users to transmit information at different data rates in one MC-CDMA system. Hence, voice, data, image and video can be transmitted seamlessly through a wireless infrastructure. The bit error rate performance of these schemes is investigated for both low-rate and high-rate users

    Data-Driven Detection and Diagnosis of System-Level Failures in Middleware-Based Service Compositions

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    Service-oriented technologies have simplified the development of large, complex software systems that span administrative boundaries. Developers have been enabled to build applications as compositions of services through middleware that hides much of the underlying complexity. The resulting applications inhabit complex, multi-tier operating environments that pose many challenges to their reliable operation and often lead to failures at runtime. Two key aspects of the time to repair a failure are the time to its detection and to the diagnosis of its cause. The prevalent approach to detection and diagnosis is primarily based on ad-hoc monitoring as well as operator experience and intuition. This is inefficient and leads to decreased availability. We propose an approach to data-driven detection and diagnosis in order to decrease the repair time of failures in middleware-based service compositions. Data-driven diagnosis supports system operators with information about the operation and structure of a service composition. We discuss how middleware-based service compositions can be monitored in a comprehensive, yet non-intrusive manner and present a process to discover system structure by processing deployment information that is commonly reified in such systems. We perform a controlled experiment that compares the performance of 22 participants using either a standard or the data-driven approach to diagnose several failures injected into a real-world service composition. We find that system operators using the latter approach are able to achieve significantly higher success rates and lower diagnosis times. Data-driven detection is based on the automation of failure detection through applying an outlier detection technique to multi-variate monitoring data. We evaluate the effectiveness of one-class classification for this purpose and determine a simple approach to select subsets of metrics that afford highly accurate failure detection

    Optimal no. Of Crew in a Workshop Subject to Minimize the Total Cost

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    Purpose: The main objective of this paper is, to determine the optimal no. of technicians’ men in a workshop crew of an Industrial System.   Theoretical framework: The purpose of applying these tools is to explore their ability to reduce costs and improvements that can be obtained in the process of providing services to the end customer.   Design/methodology/approach: The literature structure review was built from analyzing 12 of scientific papers and books, from web sciences and the Elsevier database. The papers were analyzed from descriptive, methodologic, and citation characteristics.   Finding:  By applying the equation model of the paper, the optimal no. of technician men in the crew of the workshop can be determined when it meets the lowest total costs of operating cost and technicians cost taking into account the arrival rate and the service rate.   Research practical& social implication: The data that examined in this paper assumed the number of technicians starting with the number that makes the measure of performance logical and acceptable.   Originality/ value: The paper is academic research, aimed at the application of queuing theory especially the multi-server decision, where it can lead to a better maintenance decision

    World class education and training, for world class healthcare : introducing health education England

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    Accessible user interface support for multi-device ubiquitous applications: architectural modifiability considerations

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    The market for personal computing devices is rapidly expanding from PC, to mobile, home entertainment systems, and even the automotive industry. When developing software targeting such ubiquitous devices, the balance between development costs and market coverage has turned out to be a challenging issue. With the rise of Web technology and the Internet of things, ubiquitous applications have become a reality. Nonetheless, the diversity of presentation and interaction modalities still drastically limit the number of targetable devices and the accessibility toward end users. This paper presents webinos, a multi-device application middleware platform founded on the Future Internet infrastructure. Hereto, the platform's architectural modifiability considerations are described and evaluated as a generic enabler for supporting applications, which are executed in ubiquitous computing environments
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