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As a new type of ultrasonic transducer with significant advantages, capacitive micromachined ultrasonic transducer (CMUT) has good application prospect. The reception characteristic of the CMUT is one of the important factors determining the application effect. This paper aims to study the reception characteristics of CMUT.

In this paper, the state equation is deduced and the analysis model is established in SIMULINK environment based on the lumped parameter system model of the CMUT cell. Based on this analysis model, the influencing factors of CMUT reception characteristics are studied and investigated, and the time-domain and frequency-domain characteristics are investigated in detail.

The analysis results show that parameters directly affect the reception characteristics of the CMUT, such as direct current (DC) bias voltage, input sound pressure amplitude and frequency. At the same time, the measurement system is built and the reception characteristics are verified.

This paper provides an effective method for rapid analyzing the reception characteristics of CMUT. These results provide an important theoretical basis and reference for further optimization of CMUT structure design, and lay a good foundation for the practical application measurement.

The purpose of this paper is to prepare novel electroactive shape memory nanocomposites based on graphene and study the thermomechanical property and shape memory behavior of nanocomposites.

Graphene was dispersed in N,N-dimethylformamide, and the mixture was spooned into epoxy-cyanate ester mixtures to form graphene/epoxy-cyanate ester nanocomposites. The nanocomposites were deformed under 150°C, and shape recovery test was conducted under an electric voltage of 20-100 V.

Graphene is used to improve the shape recovery behavior and performance of shape-memory polymers (SMPs) for enhanced electrical actuation effectiveness. With increment of graphene content, the shape recovery speed of nanocomposites increases significantly.

A simple way for fabricating electro-activated SMP nanocomposites has been developed by using graphene.

The outcome of this study will help to fabricate the SMP nanocomposites with high electrical actuation effectiveness and improve the shape recovery speed of the nanocomposites.

The purpose of this study is to investigate the impact of mobile self-efficacy on personal digital archiving (PDA) practices of undergraduate students.

This study used a quantitative research design for achieving the objectives. The population consisted of undergraduate students from public sector universities (the top five) of Punjab, Pakistan, listed in the Higher Education Commission recognized general universities. The data were analysed by using SmartPLS, mobile self-efficacy was the independent variable that consisted of two constructs (basic mobile phone operations and using the internet and emails). PDA practices was the dependent variable (information backup, clearing and deleting).

The analysis consisted of two major parts: first the assessment of measurement model and second the structural equation modelling analysis. A significant impact of mobile self-efficacy (basic mobile phone operations, using internet and email) was found on all the sub-constructs (information backup, information clearing and information deleting) of PDA practices. However, using internet and email has no significant impact on the information clearing practices of undergraduate students of Pakistani universities.

This study is a valuable addition to the extant literature because no comprehensive research has been carried out on the impact of mobile self-efficacy and PDA through mobile phones. It also contributes theoretically in the form of the development of a validated instrument on mobile-based PDA. Additionally, it possesses practical value for information literacy instruction programs.

Because of the small size and high integration of capacitive micromachined ultrasonic transducer (CMUT) component, it can be made into large-scale array, but this lead to high hardware complexity, so the purpose of this paper is to use less elements to achieve better imaging results. In this research, an optimized sparse array is studied, which can suppress the side lobe and reduce the imaging artifacts compared with the equispaced sparse array with the same number of elements.

Genetic algorithm is used to sparse the CMUT linear array, and Kaiser window apodization is added to reduce imaging artifacts, the beam pattern and peak-to-side lobe ratio are calculated, point targets imaging comparisons are performed. Furthermore, a 256-elements CMUT linear array is used to carry out the imaging experiment of embedded mass and forearm blood vessel, and the imaging results are compared quantitatively.

Through the imaging comparison of embedded mass and forearm blood vessel, the feasibility of optimized sparse array of CMUT is verified, and the purpose of reducing the hardware complexity is achieved.

This research provides a basis for the large-scale CMUT array to reduce the hardware complexity and the amount of calculation. At present, the CMUT array has been used in medical ultrasound imaging and has huge market potential.

The purpose of this paper is to examine whether client industry importance affects auditor independence.

This study analyzes audit firm merger data from China Stock Market and Accounting Research and uses a difference-in-difference model to find whether client industry importance is associated with auditor independence. This study uses discretionary accruals and propensity to issue modified audit opinions as proxies for auditor independence.

Results show that the greater the decline in client industry importance, the more significant the increase in auditor independence. In addition, the magnitude of decline in client overall importance is also positively associated with the extent of increase in auditor independence; however, this result disappears after controlling for client industry importance.

The authors acknowledge that this study has limitations. First, audit firm mergers provide a unique research setting. However, the findings of this study in such setting may not be generalizable to other situations. Second, this study has a limited sample size because of data availability, which could impact the robustness of the results.

Results from this study are important because investors and regulators have increasing concerns over auditor independence since the Enron scandal. To the best of the authors’ knowledge, this study is the first to examine the impact of client industry importance on auditor independence and in a unique setting of audit firm merger to separate auditor independence from auditor competence, and hence controlling for self-selection bias. Results of this study provide evidence that client industry importance has significant influence over auditor independence.

Business intelligence (BI) has been applied in various domains to take better decisions and it provides different level of information to its stakeholders according to the information needs. The purpose of this paper is to present a literature review on recent works in BI. The two principal aims in this survey are to identify areas lacking in recent research, thereby offering potential opportunities for investigation.

To simplify the study on BI literature, it is segregated into seven categories according to the usage. Each category of work is analyzed using parameters such as purpose, domain, problem identified, solution applied, benefit and outcome.

The BI contribution in various domains, ongoing research in BI, the convergence of BI domains, problems and solutions, results of congregated domains, core problems and key solutions. It also outlines BI and its components composition, widely applied BI solutions such as algorithm-based, architecture-based and model-based solutions. Finally, it discusses BI implementation issues and outlines the security and privacy policies adopted in BI environment.

In this survey BI has been discussed in theoretical perspective whereas practical contribution has been given less attention.

A comprehensive survey on BI which identifies areas lacking in recent research and providing potential opportunities for investigation.

The purpose of this paper is to review cotemporary maintenance programs and analyze factory production data for an SF₆ gas filled circuit breaker population. Various maintenance techniques and studies are reviewed to understand the reliability of circuit breaker models and the impact manufacturing can have on long term maintenance considerations.

Production and field event data were analyzed using statistical analysis tools. The population data were formatted so that a recurrent event analysis could be conducted to establish the mean cumulative function (MCF) by model and product family (class). Average Field Two‐year Recorded Event Rate (AFTRER) is introduced and compared to commonly used Field Incident Rate (FIR) and Mean‐Time between Failure (MTBF) measures.

Common managerial operating questions can be answered as exhibited for the provided circuit breaker population. This includes the longevity of field issues, the anticipated life cycle of a model or class, and AFTRER for models or classes of interest. These statistical analysis tools are used to make critical production quality and asset management observations and aid in decision‐making.

Due to limitations in existing database systems, the cost of events and explanatory variables related to event rates were not included in the analyses. There remains much work to be done in terms of the installation and retro‐fitting of breakers with conditions monitors in the field.

A framework to analyze maintenance data from fleet of similar assets using recurrent event data analysis is provided. The methods illustrated here would be useful for quality and asset managers to make operating decisions. This includes resource allocation decisions across a network of equipment.

Data analyzed are for power circuit breakers which are a critical element in the operation and reliability of the US power grid.

Using recurrent event data analysis to review and develop solutions to production quality and asset management problems including a comparison of AFTRER to FIR and MTBF measures.

The purpose of this paper is to investigate ways to reduce the average amount of exceeded guaranteed service time for external trucks at Deepwater Container Terminal Gdańsk Sp z o.o. (DCT Gdańsk) via dosing the gate activities, in particular IN-Gate entry process, of trucks carrying import/export/transit containers.

A Six Sigma methodology with the define, measure, analyze, improve, and Control (DMAIC) methods along with the SIPOC chart, cause and effect diagram, scatterplot, benchmark and brainstorming and finally multi-voting tool are used as analyses tools in this research.

DCT Gdańsk reorganized and modernized the gate operations. Gate reorganization and modernization include streaming line traffic at the gates, external parking lot optimization, implementation of dedicated supporting software and installation of dedicated CCTV cameras to provide 24 h live view. During gates development, the external truck service times data were collected and analysed. The obtained materials concerned the measurement of the average truck turnaround time before and after the implementation of the improvements.

The proposed approach of reducing the average amount of exceeded guaranteed service time of external trucks at the container terminal is unique and relatively cheap mainly due to organizational changes with some widely available low-cost investments and can be applied on a different scale to other container terminals or to transport and logistics companies.

This study aims to analyze the subsequent investment success of EMNCs after their strategic asset-seeking foreign direct investments (FDIs), while internationalization trajectories of multinational corporations from emerging economies (EMNCs) have been extensively studied, Post-internationalization investment success of EMNCs is defined as extensive technological knowledge access and transfer for knowledge combination. This paper focuses on EMNC explicit knowledge access and transfer.

This study analyzes US patents granted between 2000 and 2014 to leading innovation-oriented EMNCs from China and India as well as to their key competitors from mature industrialized countries (MMNCs). Wilcoxon Rank Sum Test is used to compare the explicit technological knowledge access and transfer patterns of EMNCs and MMNCs. With MMNCs as the benchmark, the comparison allows to imply the patterns and extent of technological knowledge access and transfer of EMNCs.

While subsidiary reverse knowledge transfer is largely missing, EMNCs adopt a parent-centric approach in which the parent directly accesses and transfers explicit knowledge from the external environment of host locations. In doing so, EMNCs at least partially achieve the knowledge access and transfer goals of strategic asset-seeking FDIs.

This study contributes to an in-depth understanding of EMNCs by empirically testing key predictions in extant EMNC literature, namely, the strategic asset-seeking in host locations and the systematic integration of accessed knowledge and resources with home country activities. This study also pioneers the use of the US patent and citation data to empirically study EMNCs.