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In this paper we propose a task based load distribution framework for Massively Multiplayer Online Games running in hybrid cloud environments. Our solution breaks down high level tasks into subtasks in such a way that i) core subtasks (those with strong timing constraints) are executed at private resources owned by game operators; while ii) background subtasks (those with looser timing/reliability...
Collective I/O is a parallel I/O technique designed to deliver high performance data access to scientific applications running on high-end computing clusters. In collective I/O, write performance is highly dependent upon the storage system response time and limited by the slowest writer. The storage system response time in conjunction with the need for global synchronisation, required during every...
Observed time difference of arrival (OTDOA) is one of the trilateration based positioning techniques adopted in 3rd generation partnership project (3GPP) long term evolution (LTE) release 9. It can estimate user's location by using received time difference of positioning reference signals (PRS) from eNBs. When user detects PRS, quantization error can occur due to low sampling resolution of narrow...
The multi-core architectures are nowadays characterized by Non-Uniform Memory Access (NUMA). Efficiently exploiting such architectures is extremely complicated for programmers. Multi-threaded programs may encounter high memory access latency if the mapping of data and computing is not considered carefully on such systems. Programmers need tools to detect performance problems if high memory access...
The paper introduces a couple of techniques for the enhanced processing of TOPSAR data. Both techniques are based on repeated passes of the sensor over the same area. The first technique combines two “de-synchronized” acquisitions, useless for interferometric purposes, to obtain an “enhanced resolution” image of the coherent scatterers in the scene. The second technique exploits the Permanent Scatterers...
We consider the problem of dimensioning resilient backbone networks for cloud-like scenarios where demand is to be served at one among several candidate data centers (DCs), and where that demand varies over time, which we assume to be slotted. We thus consider multi-period traffic, for which we need to find routes to both a primary DC and a backup DC (in case the primary, or the network connection...
The paper puts forward a design thought of phase velocity tapering in the design of 140GHz folded waveguide traveling wave tubes. It can make electron with traveling wave field synchronization again in output segment of interaction circuit. By the phase velocity analysis and optimized design, the big signal simulation is calculated in operating voltage 14.05kV and current 25mA. The efficiency is improved...
In this paper, we propose a local positioning system which can provide accurate position estimation using VHF band. The proposed system has much higher accuracy than GPS system using wide bandwidth, low RF frequency. While the GPS uses time information to calculate time of arrival between the transmitter and the receiver, the local positioning system only uses time difference information of arrival...
The utilization of Ethernet in the cellular terrestrial cloud radio access network (C-RAN) fronthaul is considered as a way for improving C-RAN network reconfigurability and efficiency in terms of both capital and operational expenditures. Moreover CPRI line bit rate dynamic reconfiguration may spare further capital expenditures by avoiding a peak traffic capacity allocation. A possible solution for...
In Rel-13, Licensed-Assisted Access (LAA) to unlicensed spectrum has been approved as a new work item to meet the increasing traffic demands for operators. For LAA, the listen-before-talk (LBT) is an efficient way to ensure fair and friendly coexistence in unlicensed band with other operators and radio access technologies (RATs). To use more bandwidth, multiple unlicensed carriers could be aggregated...
Wireless localization systems are of great importance for a variety of modern applications. Recently, cooperation among agents (nodes with unknown positions) becomes attractive in localization networks, especially in the infrastructure-limited scenario. In many cases, synchronization of the agents' clocks to the anchors (nodes with known positions) has to be performed together with the localization...
Maximum balanced load is the load above which mean packet delay and packet loss ratio increase rapidly, queues start to build up and packets start to drop. In this paper, we propose theoretical formulas to analyse the maximum balanced load in Long-Reach Passive Optical Networks (LR-PONs). This is done for two algorithms, the GIANT algorithm and a proposed BwUpdate algorithm. We compare the expressions...
The Northrop Grumman Hemispherical Resonating Gyro and Scaleable Space Inertial Reference Unit (SSIRU) system is inherently High Bandwidth. Measurements obtained at a nominal 2 KHz sample rate can provide usable bandwidth up to 600 Hz after demodulation. The standard Scalable SIRU is limited to 100 Hz output rate by CPU duty cycle constraints, which limits bandwidth to 46 Hz. Modification to the existing...
This work introduces an alternative architecture of a GNSS signal simulator, where the multiple GNSS services in the full GNSS bandwidth from L5 to L1 are generated and mixed in digital form. The digital-to-analog conversion and up-conversion to L-band is then applied to the single compounded wideband digital signal. The digital signal generation and mixing is implemented on a pair of strong GPUs...
Instead of retrieving content from a mobile infrastructure, devices may transmit it between each other, which is referred to as Device-to-Device (D2D) content delivery. This paradigm especially helps the mobile network operator to offload its infrastructure from the delivery of popular content. Private-Share is an application for the Android platform, which enables the user to synchronize content...
In all grid connected applications, Phase locked loop (PLL) is used for synchronization. The main objective of PLL technique is to precisely fast estimate the frequency and phase, when the grid voltage is unbalanced. A variety of moving average filter (MAF) has been proposed in recent literature which helps in eliminating the effect of DC offset, characteristic harmonics, and unbalanced voltage. MAF...
In this paper, we explore different techniques for lossless compression of sensor data on a wireless sensor network. In this work, we applied modify Differential Pulse Code Modulation (DPCM) scheme for our baseline lossless compression. These techniques were applied on sensor types with reasonably predictable data pattern (e.g., temperature sensor, pressure sensor, etc.) allowing about 50% data compression...
This paper introduces the control of a photovoltaic (PV) interface converter ready to offer auxiliary service - reactive power control - that also has Phasor Measurement Unit capability. A prototype of the controller is implemented using a National Instruments Compact RIO and tested using Hardware In the Loop techniques. Experimental results demonstrate the converter functionalities.
The controller area network is widely used in automobile electronics networking and for low cost embedded systems. Nondeterministic response time have restricted the wider use of CAN in safety critical real time system applications, since the CAN protocol uses “non return to zero” (NRZ) coding and includes automatic bit stuffing mechanism for synchronization. Automatic error detecting bit stuffing...
The 802.11ac MAC is designed so that competing nodes time division multiplex (TDM) on the entire 80 MHz unlicensed channel. However, since the transmission power constraint applies irrespective of the bandwidth, frequency division multiplexing (FDM) has higher system capacity than TDM. This paper presents a distributed multi-channel MAC that nearly achieves FDM without explicit knowledge or estimation...
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