An Empirical Study of Switching Behavior toward Cloud Storage Services

With the rapid development of cloud storage, it is necessary to determine the mechanism of cloud storage adoption. Based on social exchange theory, technology acceptance model and perceived risk theory, this study attempts to explore the switching factors and to empirically examine the relationship between those and users’ intention to switch to cloud storage services. This study quantitatively analyzes the data to obtain the significance level of each variable and a model of the influence mechanism of cloud storage switching intention is obtained. Our main results suggest that perceived ease of use and perceived usefulness have a significantly positive impact on related benefits. Information loss risk and time risk have a significantly positive impact on related costs while information leakage risk does not influence significantly. Related benefits have a significant positive impact on switching intention while related costs have a significantly negative impact on it

Nonlinear statistical characteristics of the multi-directional waves with equivalent energy

Directional distribution is believed to have a significant impact on the statistical characteristics in multi-directional sea states. In real sea states, short-crested waves are discrete not only in frequency but also in direction. For the former one, they are well explained in unidirectional mode, but for the latter one, they are not. In this paper, the kurtosis of short-crested waves with equivalent energy is first discussed. Unimodal-spectrum-multi-direction sea states and bimodal-spectrum-multi-direction sea states are simulated for a long time in a numerical wave basin based on the high-order spectral method. In the equivalent sea-swell sea state, the spatial evolution of kurtosis becomes more inhomogeneous, along with the maximum value of kurtosis being larger and the area where the maximum value occurs wider in the configuration with a crossing angle β = 40° than that with β = 0°, while little variations in swell-dominated and wind-sea-dominated states. A positive linear correlation between wavelet group steepness and kurtosis is obtained in a unimodal sea state, but not applied to a crossing sea state characterized by a bimodal spectrum. The exceedance probability of wave height and wave crest distribution at maximum kurtosis is also given. These findings can help predict the probability of extreme waves occurring, guiding the selection of ocean engineering sites to avoid extreme configurations

Lynx Mission Concept Status

Lynx is a concept under study for prioritization in the 2020 Astrophysics Decadal Survey. Providing orders of magnitude increase in sensitivity over Chandra, Lynx will examine the first black holes and their galaxies, map the large-scale structure and galactic halos, and shed new light on the environments of young stars and their planetary systems. In order to meet the Lynx science goals, the telescope consists of a high-angular resolution optical assembly complemented by an instrument suite that may include a High Definition X-ray Imager, X-ray Microcalorimeter and an X-ray Grating Spectrometer. The telescope is integrated onto the spacecraft to form a comprehensive observatory concept. Progress on the formulation of the Lynx telescope and observatory configuration is reported in this paper

Contemplations for the Revitalization of Traditional Fairs in Urban Centers: A Case Study of Weifang

China’s “traditional fair” culture has a long history. The “fairs” trade has existed for thousands of years, but its development characteristics and regional distribution have differed. The existing records of traditional fairs in Weifang city can be traced back to the Wanli period of the Ming Dynasty (1563), giving these fairs a history of more than 450 years. However, with the development of urbanization, traditional fairs in the city center have been destroyed: one traditional fair is disappearing almost every year. Based on this research background, the study first clarifies the significance of the existence of traditional fairs in modern life. Additionally, in our analysis, traditional fair culture can be extended to an “immaterial culture”. How to develop traditional fairs in existing urban centers has become one of the objectives of urban renewal activities at this stage. This paper describes the development and changes of fairs using the methods of site observation, questionnaire survey and interview, and Google Maps image comparison. The main results are as follows: (1) Fair culture is not only a geographical space but also a cultural space that is the inheritance and development of an intangible culture. (2) Traditional fairs include economic trade and social interaction activities. It is important to protect the life of traditional fairs, which carry a rich social function. (3) The living of the traditional fair is shrinking and is struggling to develop. Based on the changes in the traditional fairs space in Weifang city center over the past eight years, this paper puts forward the possibility of the development of a fair space in the existing central city space in order to preserve the traditional way of life and carry forward the traditional regional culture of fairs in urban construction

Parametric excitation of optomechanical resonators by periodical modulation

Optical excitation of mechanical resonators has long been a research interest, since it has great applications in the physical and engineering field. Previous optomechanical methods rely on the wavelength-dependent, optical anti-damping effects, with the working range limited to the blue-detuning range. In this study, we experimentally demonstrated the excitation of optomechanical resonators by periodical modulation. The wavelength working range was extended from the blue-detuning to red-detuning range. This demonstration will provide a new way to excite mechanical resonators and benefit practical applications, such as optical mass sensors and gyroscopes with an extended working range.NRF (Natl Research Foundation, S’pore)Published versio

Independent Effects of Dopant, Oxygen Vacancy, and Specific Surface Area on Crystal Phase of HfO2 Thin Films towards General Parameters to Engineer the Ferroelectricity

Many factors have been confirmed to affect ferroelectric phase formation in HfO2-based thin films but there was still a lack of general view on describing them. This paper discusses the intrinsic parameters to stabilize the ferroelectric phase of HfO2 thin films to approach this general view by investigating the separate effects of dopant, oxygen vacancy (VO), and specific surface area on the crystal phase of the films. It is found that in addition to extensively studied dopants, the ferroelectric orthorhombic phase can also be formed in pure HfO2 films by only introducing sufficient VO independently, and it is also formable by only increasing the specific surface area. By analyzing the common physics behind these factors, it is found that orthorhombic phase formation is universally related to strain in all the above cases with a given temperature. To get a general view, a physical model is established to describe how the strain influences ferroelectric phase formation during the fabrication of HfO2-based films based on thermodynamic and kinetics analysis

Investigating the Global Performance of the BDS-2 and BDS-3 Joint Real-Time Undifferenced and Uncombined Precise Point Positioning Using RTS Products from Different Analysis Centers

Compared to the traditional ionospheric-free (IF) precise point positioning (PPP) model, the undifferenced and uncombined (UU) PPP has the advantages of lower observation noise and the ability to obtain ionospheric information. Thanks to the IGS (International GNSS Service), real-time service (RTS) can provide RT vertical total electron content (VTEC) products, and an enhanced RT UU-PPP based on the RT-VTEC constraints can be achieved. The global performance of the BeiDou Navigation Satellite System-2 (BDS-2) and BDS-3 joint RT UU-PPP using different RTS products was investigated. There is not much difference in the RTS orbit accuracy of medium earth orbit (MEO) satellites among all analysis centers (ACs), and the optimal orbit accuracy is better than 5, 9, and 7 cm in the radial, along-track, and cross-track directions, respectively. The orbit accuracy of inclined geosynchronous orbit (IGSO) satellites is worse than that of MEO satellites. Except for CAS of 0.46 ns, the RTS clock accuracy of MEO satellites for other ACs achieves 0.2–0.27 ns, and the corresponding accuracy is about 0.4 ns for IGSO satellites. In static positioning, due to the limited accuracy of RT-VTEC, the convergence time of the enhanced RT UU-PPP is longer than that of RT IF-PPP for most ACs and can be better than 25 and 20 min in the horizontal and vertical components, respectively. After convergence, the 3D positioning accuracy of the static RT UU-PPP is improved by no more than 8.7%, and the optimal horizontal and vertical positioning accuracy reaches 3.5 and 7.0 cm, respectively. As for the kinematic mode with poor convergence performance, with the introduction of RT-VTEC constraints, the convergence time of RT UU-PPP can be slightly shorter and reaches about 55 and 60 min in the horizontal and vertical components, respectively. Both the horizontal and vertical positioning accuracies of the kinematic RT UU-PPP can be improved and achieve around 7.5 and 10 cm, respectively

Quantitative prediction of the freak wave occurrence probability in co-propagating mixed waves

The bimodal sea state, which occupies around 15%–25% of the unidirectional sea states suggested in the critical operational environment, is one of the harshest wave conditions in the field of ocean engineering. Quantitative prediction of the freak wave occurrence probability in such co-propagating mixed wave environments is crucial for marine structure designs. Based on our previous study of statistics of long-crested extreme waves, here the quantitative relation between the occurrence probability of freak waves and sea-state parameters is further investigated under bimodal spectral sea-states with equivalent energy but different energy distribution in the frequency band. Unlike the unimodal sea states, the nonlinear interaction process of the co-propagating mixed waves is challenging to theoretically obtain the maximum kurtosis versus their characteristics. In this study, we develop the relation of the maximum kurtosis between single-peak and bimodal wave trains by introducing energy distribution and frequency separation with an empirical formula. A quantitative relation between the occurrence probability of freak waves and kurtosis in co-propagating mixed waves is obtained. It enables the fast and accurate prediction of the occurrence probability of freak waves in the operational area for a given bimodal sea state. This work provides a conservative reference threshold for offshore engineering and ship navigation, as well as ideas and methods for seeking a universal result applicable for practical application