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Large-scale systems use distributed data processing systems in their work. An important problem in the design of such systems is the optimal allocation of data files by the nodes of the computer network. The article deals with the problem of the optimal allocation of files and their copies over the nodes of an unreliable large-scale distributed system.
The natural disasters affecting railway are characterized by universality, frequency and variety in china. These events can suddenly cause a greater negative impact on the order of rail transport organizations in a short time. The abnormal circumstances of network node or network range will pose a threat to the safety and efficiency of rail transport. On the basis of analyzing the causes of the problem...
Prof. Edward Crawley has stated what an architecture is through the so-called FCF paradigm: "Architecture [..] consists of: Function, related by Concept, to Form". This definition has the merit to be simple, operative and applicable to all kind of engineered systems. However, by reviewing it thoroughly, we may expose some limitation, especially when trying to set-up a framework for architecture...
Human activity patterns such as communication and cooperation rely in large parts on smartphone-based interaction. Day-to-day available communication means are taken for granted. But in scenarios where communication infrastructure is broken, such as in the aftermath of a disaster, communication establishment becomes crucial. In those post-disaster conditions ubiquitous mobile devices carried by humans...
Memory leaks are one of the primary causes of software aging. Despite of recent countermeasures in C/C++ such as smart pointers, leak-related defects remain a troublesome issue in C/C++ code, especially in legacy applications.We propose an approach for automatic detection of memory leaks in C/C++ programs based on characterizing memory allocation sites via the age distribution of the non-disposed...
Optical instruments for space applications are rather delicate subjects as customer demands are typically high in terms of performance and environmental conditions are harsh. For the development of such systems a highly integrated engineering team consisting of specialists from various technical disciplines is mandatory as thermal, structural and optical properties are impacting directly the imaging...
The IEEE802.15.4e standard for Iow power wireless sensor networks defines a new mode called Time Slotted Channel Hopping (TSCH) as Medium Access Control (MAC). TSCH allows highly efficient deterministic time-frequency schedules that are built and maintained by the 6TiSCH operation sublayer (6top). In this paper, we propose a solution to limit the allocation of identical cells to co-located pair of...
Dynamic Adaptive Streaming over HTTP (DASH) is a predominant technology for delivering video in wired and wireless networks. With DASH, clients can adaptively select the quality (bitrate) of the downloaded video. To improve Quality of Experience (QoE), a recently standardized framework, called Server and Network Assisted DASH (SAND), allows the client and the server to exchange control information...
In order to provide ubiquitous communication, seamless connectivity is now required in all environments including highly mobile networks. By using vertical handover techniques, it is possible to provide uninterrupted communication as connections are dynamically switched between wireless networks as users move around. However, in a highly mobile environment, traditional reactive approaches to handover...
In this paper, we jointly consider communication, caching and computation in a multi-user cache-assisted mobile edge computing (MEC) system, consisting of one base station (BS) of caching and computing capabilities and multiple users with computation-intensive and latency-sensitive applications. We propose a joint caching and offloading mechanism which involves task uploading and executing for tasks...
In Bike-Sharing System (BSS), great efforts have been devoted to performing resources prediction, redistribution and trip planning to alleviate the unbalance of resources and inconvenience of bike utilization caused by the explosion of users. However, there is few work in trip planning noticing that the complete trip composes of three segments: from user's start point to a start station, from the...
In order to meet the demand of CNC system based on function safety, this article analyzes software design of CNC system based on function safety and a safety components sharing mechanism is proposed. At the same time, a method of security threshold distribution for software of CNC system is presented. This method establishes the system structure model of the CNC system software the relative weight...
In this work we present a framework and quantitative metric for comparing the performance and resiliency of goal assignment strategies in the context of autonomous, disaster-site exploration using a heterogeneous team of robots. We propose three feasible policies for assigning user-defined Areas-of-Interest amongst a team of an Unmanned Ground Vehicle (UGV) and a squadron of Unmanned Aerial Vehicles...
In order to succeed in updating ECU program without specific downloader, this paper designed and developed a Bootloader based on CCP protocol, which has the advantages of high flexibility, good portability. This system uses three steps– import of Bootloader, operation of the Bootloader and import of new ECU program–to realize online program upgrade for freescale chip MC9S12P64. Finally, this thesis...
Automatic demand side response is well applied and popularized with the development of active power distribution network technology. In this paper, with the specific condition of urban commercial centers considered, the generalized demand side resources co-optimization is presented here including load side resources and energy storage resources. Firstly, for the normal operation of power systems,...
This paper presents basic considerations on the mixed support of TDMA (Time Division Multiple Access) and SCPC (Single Channel Per Carrier) transmission for satellite disaster communications network. Since each of TDMA and SCPC transmission has its own advantages in efficiency and flexibility according to the network characteristics, integral use of them could lead to the improvements in bandwidth...
The integration of Device-to-Device (D2D) communication into a cellular network improves system spectral efficiency, increases capacity, reduces power consumption and also reduces traffic to the evolved NodeB (eNB). However, D2D communication generates interference to the conventional cellular network which deteriorates the system performance. In this paper, we propose a radio resource allocation...
This paper presents an algorithm for Distributed Generation (DG) allocation planning, using fuzzy set theory and fuzzy multi criteria decision making based on the Bellman-Zadeh method. The proposed model considers power losses and investment deferral values on one side (goals) and line currents, node voltages and short circuit power values on the other (constraints). The objective of this work is...
As the conventional QAM has a square constellation, PAPR is high due to the corner signal points. To overcome this, the (3 × 2m)-ary QAM with even m was proposed recently. For odd m, the rectangular constellation has high PAPR and perfect Gray code, while the diamond constellation has low PAPR and imperfect Gray code. In this paper, we propose a scheme assigning quasi-Gray code to the diamond constellation...
In our paper, a novel method is proposed to obtain the optimal positions of secondary base stations (SBSs) for cognitive radio Internet of Things (IoT) sensor networks and to select the optimal operating channel in order to maximize the secondary capacity, while also protecting the primary systems. We proposed an appearance probability matrix for secondary IoT sensor devices in order to maximize the...
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