Blind Channel Identification for Cyclic-Prefixed MIMO-OFDM Systems with Virtual Carriers

This paper applies the repetition index scheme(RIS)to the channel identification of cyclic prefixed(CP)multiple-input multiple-output orthogonal frequency division multiplexing(MIMO-OFDM)systems with virtual carriers(VCs)in the environment of the number of receive antennas being no less than that of transmit antennas.The VCs will cause a rank deficiency problem in computing the subspace information.With the subcarrier mapping matrix,the received signal is simplified to remove the rank deficiency.We use the RIS scheme to generate many times of equivalent symbols so the channel identification can converge with few received OFDM blocks.The RIS scheme will convert the white noise into non-white noise.With the Cholesky factorization,a noise whitening technique is developed to turn the non-white noise back to white noise.We further analyze the necessary conditions of identifiability of channel estimation.Simulations are performed to show the superiority of the proposed method.     

Computer-assisted yoga training system

Multimedia Tools and Applications - Self-training is essential in sports exercise. However, without the instruction of a coach, a practitioner may progress to a limited extent. Improper postures...     

A framework for self‐regulated digital learning (SRDL)

This article develops a framework for self‐regulated digital learning, which supports for self‐regulated learning (SRL) in e‐learning systems. The framework emphasizes 8 features: learning plan, records/e‐portfolio and sharing, evaluation, human feedback, machine feedback, visualization of goals/procedures/concepts, scaffolding, and agents. Each feature facilitates or supports one or more SRL skills, including planning, monitoring and evaluating learning, applying appropriate cognitive strategies, and setting standards of products or performance. The implementation in domain‐general and ‐specific systems as illustrated by web‐based inquiry and problem‐solving are discussed. Examples and learning effects are elicited from the literature to demonstrate various designs. Approaches for designing SRL systems, educational implications, and new directions for future research incorporating SRL into digital learning are presented.     

Exploring Factors Affecting the Adoption of Internet of Things Services

The Internet of things (IoT) is seen as a potentially effective means of integrating multiple technologies to improve the quality of life. However, little attention has been paid to factors that may have a significant effect on a user’s intention to use the IoT services. This study applies the value-based adoption model to examine the influences of benefits (i.e. perceived usefulness and perceived enjoyment) and sacrifices (i.e. perceived privacy risk and perceived costs) on the user’s perceived value of and intention to use the IoT services. A structural equation modeling approach is applied to a survey of 489 IoT users, with results indicating that perceived usefulness and perceived enjoyment significantly affect behavioral intention through perceived value. Moreover, perceived privacy risk also plays a key factor in determining IoT adoption. The implications of this study are discussed.     

Numerical simulation and experimental validation of novel hyperelastic micro-motion manipulator for water conserving device

Microsystem Technologies - The aim of this study was to evaluate a novel water-conserving micro-motion manipulator (manipulator) for application in the fluid flow rate regulator of a faucet through...     

Technology executives in the changing accounting information environment: Impact of IFRS adoption on CIO compensation

Accounting regulatory changes that affect the information technology (IT) infrastructure of firms have prompted Chief Information Officers (CIOs) to take the lead in aligning IT changes with new reporting requirements. This study investigates the associations between the mandatory adoption of International Financial Reporting Standards (IFRS) and CIO compensation. We find a significant increase in CIO compensation in the post-IFRS period, which is higher in non-IT firms than in IT firms. Moreover, pay is at a premium for CIOs equipped with more educational background in business. We discuss the implications of our study and offer suggestions for future research.     

Lightweight and flexible key distribution schemes for secure group communications

Wireless Networks - Key distribution is one of the most fundamental cryptographic primitives that can establish secure group communications in both centralized and distributed networks. A one-time...     

An investigation of the impact of cognitive absorption on continued usage of social media in Taiwan: the perspectives of fit

Information processing view explains the fit between information processing need and information processing capability to achieve optimal performance. This research observes that the model of users’ needs-functional capabilities fits by two perspectives of holistic and reductionistic in the context of social media usage. Through an online survey of 310 Facebook users in Taiwan, the findings provide the holistic and reductionistic perspectives of the fit between users’ needs and functional capabilities as having a significant impact on users’ cognitive absorption. Thus, social media providers must emphasise managing the fit between users’ needs and functional capabilities for their products and services development.     

Information technology adoption for sustainable development: green e-books as an example*

ABSTRACT

In recent years, due to increasing awareness of the need for environmental protection, there have been significant efforts to improve consumers’ acceptance of green information technology(IT) products for sustainable development. This study first investigated how knowledge about a green IT product (e-books) influences consumers’ planning processes by using the technology acceptance model and the theory of planned behavior. Data from 320 respondents were analyzed using structural equation modeling to examine the hypothesized relationships in the research model. Results show that perceived usefulness, attitudes, subjective norms, and perceived behavioral control have a significant and positive impact on the intention to purchase e-books. Results also show the moderating effect of consumers’ knowledge about the environmental friendliness of e-books on their intention to buy e-books. Finally, important implications of the findings are discussed, and directions for future research are also provided in this paper.     

Effect of Pre-Melting Time on Crystallization of Poly(ethylene terephthalate)

In this study poly(ethylene terephthalate) (PET) was melted at 300°C, approximately 46°C above the crystalline melting point, T _m, for different times, i.e., Δt _m,=5, 8, and 10 min, and then quenched to different isothermal crystallization temperatures, T _c, ranging from 190°C to 230°C. The effect of pre-melting time, Δt _m, at 300°C on the degree of crystallinity and on crystalline morphology were investigated by differential scanning calorimetry (DSC) and polarized-light microscopy (PLM). After crystallization at low T _c, PLM data revealed the PET contained usual, positive, and unringed spherulites. After crystallization at high T _c PET contained unusual, ringed, and double-extinction spherulites. The experimental results reveal that increasing the pre-melting time Δt _m at 300°C causes an increment in T _c for usual–unusual, unringed–ringed, and positive–double-extinction transitions of the PET spherulites. The experimental results also show that PET with a pre-melting time Δt _m=8 min had higher crystallinity than those with pre-melting times Δt _m=5 and 10 min. These crystallization phenomena were attributed to the different numbers of residual unmelted PET crystallites as a result of the variation in pre-melting time, Δt _m, at 300°C.