961 research outputs found
ATMOSPHERIC EFFECTS ON RTK NETWORK IN FLORIDA
Commonly used real time kinematic (RTK) network (RTK Network) techniques, i.e., MAX, I-MAX, FKP and VRS, are tested by taking monthly measurements for a year in Florida. Additionally, RTCM message versions 2 and 3 are used with I-MAX and VRS measurements. The results revealed that mostly, horizontal coordinates vary a few centimeters and generally changes in vertical coordinates are less than two decimeters. In terms of horizontal coordinates, the best results are produced by I-MAX3 method and FKP yielded the worst results. In terms of vertical coordinates, almost all results look alike; however, the best results are produced by VRS3 method. It appears that I-MAX3 performed better than I-MAX2 and VRS3 performed better than VRS2. Yet, MAX did not stand out among other techniques
PRECISE FORMULA FOR VOLUME COMPUTATIONS USING CONTOURS METHOD
Except some special cases, commonly used volume computation methods are grids method, contours method and volume computations by utilizing TIN (Triangulated Irregular Network). In this study, to investigate the precisions of these techniques, a grid system is established in an undulating area and volume of the mound is determined by using these three volume computation methods. It is found out that contour method results were not as price as the other two methods. Thus, a precise formula for volume computations using contours method is proposed.Except some special cases, commonly used volume computation methods are grids method, contours method and volume computations by utilizing TIN (Triangulated Irregular Network). In this study, to investigate the precisions of these techniques, a grid system is established in an undulating area and volume of the mound is determined by using these three volume computation methods. It is found out that contour method results were not as price as the other two methods. Thus, a precise formula for volume computations using contours method is proposed
Frontline professionals in the age of institutional rearrangement: the case of needs assessment for public services
Session 3: Institutional rearrangement of the public domai
Interplay between structure and magnetism in nanowires
We investigate the equilibrium geometry and electronic structure of
MoSI nanowires using ab initio Density Functional
calculations. The skeleton of these unusually stable nanowires consists of
rigid, functionalized Mo octahedra, connected by flexible, bi-stable sulphur
bridges. This structural flexibility translates into a capability to stretch up
to approximate 20% at almost no energy cost. The nanowires change from
conductors to narrow-gap magnetic semiconductors in one of their structural
isomers.Comment: 4 pages with PRL standards and 3 figure
Failure of conventional retrograde cystography to detect bladder ruptures in pelvic trauma
Conventional retrograde cystography is often used to investigate patients with suspected bladder ruptures in pelvic trauma. Clinical indicators suggestive of a rupture include haematuria and suprapubic tenderness and should increase the suspicion of bladder and urinary tract injury and prompt the clinician to undertake further investigations. Two patients with high-energy pelvic fractures had bladder ruptures detected intraoperatively despite normal preoperative retrograde cystogram. Both patients had significant clinical indicators suggestive of underlying bladder and urinary tract injury. In both cases, a routine conventional retrograde cystogram was performed but failed to identify the full extent of the bladder injury. A possible reason for misdiagnosis in these cases is the delay between injury and investigation due to tertiary referral of care
Design of a cosine pulse transceiver operating in the discrete-time domain
Introduction/purpose: The paper presents the theory and the design issues of a transceiver for a discrete-time cosine pulse transmission. The operation of the transceiver and all signals are analyzed in both time and frequency domains. Methods: The detailed theoretical models of the transmitter and the receiver are presented based on their block schematics expressed in terms of mathematical operators. The transceiver blocks are simulated and the results of their simulation are presented and compared with the theoretical results. Results: Discrete-time signals at the input and the output of each transceiver block are derived in the mathematical form and presented in the time and frequency domain. A transceiver simulator is developed in Matlab. The simulation results confirmed the theoretical findings. Conclusion: The results of this work contribute to the theoretical modeling and design of modern transceivers that can be used for discrete-time cosine pulse transmission
Mathematical modeling and simulation of a rectangular pulse transceiver operating in the discrete-time domain
Introduction/purpose: The paper presents the theory and design issues of
a discrete-time communication system used for discrete-time pulse
transmission with and without filtering. Signals are analyzed in both the time
domain and the frequency domain.
Methods: The system is theoretically analyzed using block schematics
expressed in terms of mathematic operators and the system simulation is
performed to confirm the theoretical findings.
Results: Discrete-time signals are presented in the time domain and the
frequency domain as well as confirmed by a simulation designed in Matlab.
Conclusion: The results of the paper contribute to the theoretical modeling
and design of modern discrete communication systems
Facilitating the driver detection of road surface type by selective manipulation of the steering-wheel acceleration signal
Copyright @ 2012 by Institution of Mechanical Engineers.Previous research has investigated the possibility of facilitating the driver detection of road surface type by means of selective manipulation of the steering-wheel acceleration signal. In previous studies a selective increase in acceleration amplitude has been found to facilitate road-surface-type detection, as has selective manipulation of the individual transient events which are present in the signal. The previous research results have been collected into a first guideline for the optimization of the steering-wheel acceleration signal, and the guideline has been tested in the current study. The test stimuli used in the current study were ten steering-wheel acceleration-time histories which were selected from an extensive database of road test measurements performed by the research group. The time histories, which were all from midsized European automobiles and European roads, were selected such that the widest possible operating envelope could be achieved in terms of the r.m.s. value of the steering acceleration, the kurtosis, the power spectral density function, and the number of transient events present in the signal. The time histories were manipulated by means of the mildly non-stationary mission synthesis algorithm in order to increase, by a factor of 2, both the number and the size of the transient events contained within the frequency interval from 20 Hz to 60Hz. The ensemble, composed of both the unmanipulated and the manipulated time histories, was used to perform a laboratory-based detection task with 15 participants, who were presented the individual stimuli in random order. The participants were asked to state, by answering 'yes' or 'no', whether each stimulus was considered to be from the road surface that was displayed in front of them by means of a large photograph on a board. The results suggest that the selectively manipulated steering-wheel acceleration stimuli produced improved detection for eight of the ten road surface types which were tested, with a maximum improvement of 14 per cent in the case of the broken road surface. The selective manipulation did lead, however, to some degradation in detection for the motorway road stimulus and for the noise road stimulus, thus suggesting that the current guideline is not universally optimal for all road surfaces
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