116 research outputs found
Extensiveness of business planning and firm survival: an examination into the drivers of success and survival for knowledge intensive start-up firms
A number of studies have found that writing a business plan increases the likelihood of firm survival. For instance, Liao and Gartner (2006) found that firms that completed a business plan were nearly three times more likely to launch their business than those that did not. On the contrary, other studies have found no association between writing a business plan and success. For example, Honig and Karlsson (2004) found evidence that entrepreneurs only write business plans because they are required to do so by investors, educators and advisors. While the evidence is mixed on the effectiveness of business planning, previous research has not examined individual elements of business plans. Thus, it is not clear which aspects (e.g., financial projections v. marketing strategy) of business planning are positively (or negatively) related to performance and survival. Our study addresses two main issues concerning the impact of business planning in firm survival: 1) Are surviving firms different in the extent of their business planning? 2) Which topical areas within business planning are more (or less) predictive of firm survival? To seek answers, we reconceptualize business planning along four dimensions: service/product description, marketing strategy, financial projections and organizational planning
Investigating electron precipitation events using near-conjugate observations from St Johns, New Foundland, and Halley, Antarctica
A characterization of periodicity in the voltage time series of a riometer
Author Posting. © American Geophysical Union, 2020. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Space Physics 125(7), (2020): e2019JA027160, doi:10.1029/2019JA027160.This paper reveals unprecedented periodicity in the voltage series of relative ionospheric opacity meters (riometers) of the Canadian Riometer Array (CRA). In quiet times, the riometer voltage series is accurately modeled by a stochastic process whose components include both a six term expansion in harmonic functions and some amplitude modulated modes of lower signal to noise ratio (SNR). In units of cycles per sidereal day (cpsd), the frequencies of the six harmonic functions lie within 0.01 cpsd of an integer. Earth's rotation induces a splitting of the low SNR components, resulting in the appearance of nine multiplets in standardized power spectrum estimates of the considered CRA voltage series. A second feature of these spectrum estimates is a 6 min periodic element appearing in both the CRA voltage series and the proton mass density series of the Advanced Composition Explorer (ACE). Spectral peak frequencies have been detected, which lie near established solar mode frequency estimates. In addition, some of these peak frequency estimates are coincident with peak frequency estimates of the standardized power spectra for the time series of proton mass density and interplanetary magnetic field strength (IMF) at ACE.“Marshall_Francois_Supporting_Information_JGR_2019.pdf” contains a summary of the supporting information. The 1 hr sampled F10.7 series was obtained from DRAO (National Research Council, 2017). The three MAG time series of IMF strength were acquired from The ACE Science Center (2007), while the SWEPAM time series of proton mass density was acquired from Space Weather Prediction Center, National Oceanic and Atmospheric Administration (2018). The relevant data sets for the analysis of this paper are included in Marshall (2019). This work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), Canadian Statistical Sciences Institute (CANSSI), Bonneyville Power Authority, and Queen's University. David J. Thomson, the official holder of the grants and contracts, provided research and conference funding to advance this project. Special thanks to Ken F. Tapping (DRAO of NRCan) for his guidance in finding the data sets relevant to solar radio emissions. Glen Takahara, of the Department of Mathematics and Statistics at Queen's University, suggested exploring different data sets to confirm the modal origin of spectral peaks observed in the Ottawa riometer of the CRA. Alessandra A. Pacini of the Arecibo Observatory recommended checking to see if some of the modes could have been driven by the harmonics of Earth's rotation. Frank Vernon of the Institute of Geophysics and Planetary Physics at Scripps Institution of Oceanography confirmed how seismic data could be expected to reveal coincident spectral peaks at the detected frequencies in the riometer standardized spectra.2020-10-2
Evaluating the applicability of the finite element method for modelling of geoelectric fields
Assimilative real-time models of HF absorption at high latitudes
Improved real-time HF communications frequency management is required for aircraft on trans-polar routes. Polar cap absorption (PCA) models have therefore been adapted to assimilate real-time measurements of zenithal cosmic radio noise absorption (~ 30 MHz) from a large network of online riometers in Canada and Finland. Two types of PCA model have been developed and improvements to model accuracy following optimisation are quantified. Real-time optimisation is performed by age-weighting riometer measurements in a non-linear regression. This reduces root-mean-square errors (RMSE) from 2-3 dB to less than 1 dB and mean errors to within ±0.2 dB over a wide latitude range. This paper extends previous work by further optimising the models’ dependences on solar-zenith angle to account for differences in the ionospheric response at sunrise and sunset (the Twilight Anomaly). Two models of the rigidity cutoff latitudes are compared and one is optimised in real time by regression to riometer measurements. Whilst measurements from the NASA POES satellites may provide a direct measurement of the rigidity cut-off, it is observed that proton flux measurements from POES often need correcting for relativistic electron contamination for several hours at the start of a PCA event. An optimised real-time absorption model will be integrated into HF ray-tracing propagation predictions relating to measurements of HF signal strengths on a network of HF transmitters and receivers in the high northern latitudes
The wave of wood : forestry's economic contribution to South Carolina's economy in 2018
The purpose of this study is to update the economic contribution of forestry to South Carolina's economy for 2018 and to show the relative magnitude of forestry's major sectors. This study includes business sectors that have a direct and logical connection to the state's forest resource
Developments in an HF Nowcasting Model for Trans-Polar Airline Routes
HF communications can be difficult in the polar regions since they are strongly influenced by space weather events. Airline communications within the polar regions rely on HF communications and improved nowcasting and forecasting techniques in support of this are now required. Previous work has demonstrated that ray tracing through a realistic, historical ionosphere provides signal coverage in good agreement with measurements. This paper presents an approach to providing a real-time ionospheric model by assimilating TEC measurements and validates it against observations from ionosondes
Developments in HF Propagation Predictions to Support Communications with Aircraft on Trans-polar Routes
Commercial airlines began operations over polar routes in 1999 with a small number of proving flights. By 2014 the number had increased to in excess of 12,000 flights per year, and further increases are expected. For safe operations, the aircraft have to be able to communicate with air traffic control centres at all times. This is achieved by VHF links whilst within range of the widespread network of ground stations, and by HF radio in remote areas such as the Polar regions, the North Atlantic and Pacific where VHF ground infrastructure does not exist. Furthermore, the Russian side of the pole only has HF capability. This has created a demand for improved HF nowcasting and forecasting procedures to support the polar operations, which are the subject of this paper
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