428 research outputs found
Relationship development with customers on facebook: A critical success factors model
© 2015 IEEE. Social Networking Sites have been increasingly used by organizations to communicate with and manage relationship with existing and new customers. Through a review of the literature, content analysis of online discussions, and a set of interviews with SNS experts, this study has developed a critical success factor model for effective customer relationship management on Facebook. The model suggests seven critical factors: (i) Develop a strategic SNS plan, (ii) Ability to measure and monitor outcomes, (iii) Integrating SNS activities with other forms of marketing, (iv) Let the users/consumers participate, (v) Being committed to SNS task, (vi) Regular updates on the SNS, and (vii) Try to be honest and authentic during the campaign
Dynamic Properties of Sand in Constant-Volume and Constant-Load Tests
Constant-volume and constant-load tests were performed on Babolsar and Toyoura sands by using a modified SGI cyclic simple shear device which provides the capability of back pressure saturation. All tests were shear strain controlled and conducted under different values of relative density, vertical effective stress and shear strain amplitude. Results revealed that Dr, σ′v and γ affect shear modulus and damping ratio under both constant-volume and constant-load conditions in similar ways except the shear strain amplitude which has no important influence on damping of constant-volume tests. The effects of Dr, σ′v, γ and the number of cycles on variations of shear modulus and damping ratio of sand were found to be more pronounced under constant-load condition. It seems that the differences between the results may be due to the different fabric produced in two kinds of test samples rather than to the test method. However, further study is needed to clarify this issue
High-frequency Oscillations in Small Magnetic Elements Observed with Sunrise/SuFI
We characterize waves in small magnetic elements and investigate their
propagation in the lower solar atmosphere from observations at high spatial and
temporal resolution. We use the wavelet transform to analyze oscillations of
both horizontal displacement and intensity in magnetic bright points found in
the 300 nm and the Ca II H 396.8 nm passbands of the filter imager on board the
Sunrise balloon-borne solar observatory. Phase differences between the
oscillations at the two atmospheric layers corresponding to the two passbands
reveal upward propagating waves at high frequencies (up to 30 mHz). Weak
signatures of standing as well as downward propagating waves are also obtained.
Both compressible and incompressible (kink) waves are found in the small-scale
magnetic features. The two types of waves have different, though overlapping,
period distributions. Two independent estimates give a height difference of
approximately 450+-100 km between the two atmospheric layers sampled by the
employed spectral bands. This value, together with the determined short travel
times of the transverse and longitudinal waves provide us with phase speeds of
29+-2 km/s and 31+-2 km/s, respectively. We speculate that these phase speeds
may not reflect the true propagation speeds of the waves. Thus, effects such as
the refraction of fast longitudinal waves may contribute to an overestimate of
the phase speed.Comment: 14 pages, 7 figure
A methodology for project portfolio selection under criteria prioritisation, uncertainty and projects interdependency – combination of fuzzy QFD and DEA
© 2018 Elsevier Ltd Resources of an organisation (people, time, money, equipment, etc) are never endless. As such, a constant and continuous challenge for decision makers is to decide which projects should be given priority in terms of receiving critical resources in a way that the organisation's productivity and profitability is best guaranteed. Previous literature has already developed a plenitude of project portfolio selection methodologies ranging from simple scoring to complex mathematical models. However, most of them too often fail to propose one integrated and seamless method that can simultaneously take into account three important elements: (1) prioritisation of selection criteria over each other, (2) uncertainty in decision-making, and (3) projects interdependencies. This paper aims to fill this gap by proposing an integrated method that can simultaneously address all these three aspects. The proposed method combines Quality Function Development (QFD), fuzzy logic, and Data Envelopment Analysis (DEA) to accounts for prioritisation, uncertainty and interdependency. We then apply this method in a numerical example from a real world case to illustrate the applicability and efficacy of the proposed methodology
Migration of Ca II H bright points in the internetwork
The migration of magnetic bright point-like features (MBP) in the lower solar
atmosphere reflects the dispersal of magnetic flux as well as the horizontal
flows of the atmospheric layer they are embedded in. We analyse trajectories of
the proper motion of intrinsically magnetic, isolated internetwork Ca II H MBPs
(mean lifetime 461 +- 9 s) to obtain their diffusivity behaviour. We use
seeing-free high spatial and temporal resolution image sequences of quiet-Sun,
disc-centre observations obtained in the Ca II H 3968 {\AA} passband of the
Sunrise Filter Imager (SuFI) onboard the Sunrise balloon-borne solar
observatory. Small MBPs in the internetwork are automatically tracked. The
trajectory of each MBP is then calculated and described by a diffusion index
({\gamma}) and a diffusion coefficient (D). We further explore the distribution
of the diffusion indices with the help of a Monte Carlo simulation. We find
{\gamma} = 1.69 +- 0.08 and D = 257 +- 32 km^2/s averaged over all MBPs.
Trajectories of most MBPs are classified as super-diffusive, i.e., {\gamma} >
1, with the determined {\gamma} being to our knowledge the largest obtained so
far. A direct correlation between D and time-scale ({\tau}) determined from
trajectories of all MBPs is also obtained. We discuss a simple scenario to
explain the diffusivity of the observed, relatively short-lived MBPs while they
migrate within a small area in a supergranule (i.e., an internetwork area). We
show that the scatter in the {\gamma} values obtained for individual MBPs is
due to their limited lifetimes. The super-diffusive MBPs can be well-described
as random walkers (due to granular evolution and intergranular turbu- lence)
superposed on a large systematic (background) velocity, caused by granular,
mesogranular and supergranular flows.Comment: 10 pages, 7 figures, 3 table
Search Engine Advertising Adoption and Utilization: An Empirical Investigation of Inflectional Factors
© Taylor & Francis Group, LLC. Search engine advertising (SEA) is a prominent source of revenue for search engine companies, and also a solution for businesses to promote their visibility on the web. However, there is little academic research available about the factors and the extent to which they may influence businesses’ decision to adopt SEA. Building on Theory of Planned Behavior, Technology Acceptance Model, and Unified Theory of Acceptance and Use of Technology, this study develops a context-specific model for understanding the factors that influence the decision of businesses to use SEA. Using structural equation modeling and survey data collected from 142 businesses, this research finds that the intention of businesses to use SEA is directly influenced by four factors: (i) attitude toward SEA, (ii) subjective norms, (iii) perceived control over SEA, and (iv) perceived benefits of SEA in terms of increasing web traffic, increasing sales and creating awareness. Furthermore, the research we discover six additional factors that have an indirect influence: (i) trust in search engines, (ii) perceived risk of SEA, (iii) ability to manage keywords and bids, (iv) ability to analyze and monitor outcomes, (v) advertising expertise, and (vi) using external experts
Height dependence of the penumbral fine-scale structure in the inner solar atmosphere
We studied the physical parameters of the penumbra in a large and
fully-developed sunspot, one of the largest over the last two solar cycles, by
using full-Stokes measurements taken at the photospheric Fe I 617.3 nm and
chromospheric Ca II 854.2 nm lines with the Interferometric Bidimensional
Spectrometer. Inverting measurements with the NICOLE code, we obtained the
three-dimensional structure of the magnetic field in the penumbra from the
bottom of the photosphere up to the middle chromosphere. We analyzed the
azimuthal and vertical gradient of the magnetic field strength and inclination.
Our results provide new insights on the properties of the penumbral magnetic
fields in the chromosphere at atmospheric heights unexplored in previous
studies. We found signatures of the small-scale spine and intra-spine structure
of both the magnetic field strength and inclination at all investigated
atmospheric heights. In particular, we report typical peak-to-peak variations
of the field strength and inclination of G and , respectively, in the photosphere, and of G and
in the chromosphere. Besides, we estimated the vertical
gradient of the magnetic field strength in the studied penumbra: we find a
value of G km between the photosphere and the middle
chromosphere. Interestingly, the photospheric magnetic field gradient changes
sign from negative in the inner to positive in the outer penumbra.Comment: 14 page, 9 figures, accepted for Ap
High-resolution wave dynamics in the lower solar atmosphere
The magnetic and convective nature of the Sun's photosphere provides a unique
platform from which generated waves can be modelled, observed, and interpreted
across a wide breadth of spatial and temporal scales. As oscillations are
generated in-situ or emerge through the photospheric layers, the interplay
between the rapidly evolving densities, temperatures, and magnetic field
strengths provides dynamic evolution of the embedded wave modes as they
propagate into the tenuous solar chromosphere. A focused science team was
assembled to discuss the current challenges faced in wave studies in the lower
solar atmosphere, including those related to spectropolarimetry and radiative
transfer in the optically thick regions. Following the Theo Murphy
international scientific meeting held at Chicheley Hall during February 2020,
the scientific team worked collaboratively to produce 15 independent
publications for the current Special Issue, which are introduced here.
Implications from the current research efforts are discussed in terms of
upcoming next-generation observing and high performance computing facilities.Comment: 16 pages, 4 figures, Introduction to the "High-resolution wave
dynamics in the lower solar atmosphere" special issue of the Philosophical
Transactions A: https://walsa.team/u/rst
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