Development of a survey instrument to measure TEFL academics' perceptions about, individual and workplace characteristics for conducting research

The Chinese Ministry of Education (MOE) initiatives to improve the English competence of college students, as well as increased proficiency level of entering college students (Cheng, 2002) have contributed to greater demands on Teaching English as a Foreign Language (TEFL) academics (MOE, 2004), as “the upgrading of national English proficiency, then, is predicated largely on the professional competence of the teaching force” (Hu, 2005, p. 655). For TEFL academics, one component of this competence is the capacity to conduct research (Shu, 2002), which also reflects other changes in Chinese higher education. The aspirations of higher education institutions at all levels have led to more rigorous recruitment policies and promotion requirements (Che, 2004; Wang, 2007), stressing research as an important indicator of academics’ performance (Shi, 2002; Pan, 2006). These changes highlight the role of research in higher education institutions’ efforts to raise their national status and world ranking (Zhang, Wang, & He, 2006), and have exerted influences on faculty’s academic role. Academics are obliged to engage in research activities, and this has posed challenges to teaching-oriented institutions and disciplines

Optically stimulated luminescence in vivo dosimetry for radiotherapy: physical characterization and clinical measurements in (60)Co beams

A commercial optically stimulated luminescence (OSL) dosimetry system was investigated for in vivo dosimetry in radiation therapy. Dosimetric characteristics of InLight dot dosimeters and a microStar reader (Landauer Inc.) were tested in (60)Co beams. The reading uncertainty of a single dosimeter was 0.6%. The reproducibility of a set of dosimeters after a single irradiation was 1.6%, while in repeated irradiations of the same dosimeters it was found to be 3.5%. When OSL dosimeters were optically bleached between exposures, the reproducibility of repeated measurements improved to 1.0%. Dosimeters were calibrated for the entrance dose measurements and a full set of correction factors was determined. A pilot patient study that followed phantom validation testing included more than 100 measured fields with a mean relative difference of the measured entrance dose from the expected dose of 0.8% and the standard deviation of 2.5%. In conclusion, these results demonstrate that OSL dot dosimeters represent a valid alternative to already established in vivo dosimetry systems

A stiffness derivative local hypercomplex-variable finite element method for computing the energy release rate

A “local” hypercomplex-variable finite element method, L-ZFEM, is proposed for the computation of the energy release rate (ERR) using the stiffness derivative equation. This approach is analogous to the stiffness derivative method proposed by Parks and Hellen but has superior numerical accuracy. In addition, this method is significantly more efficient than the previously published “global” hypercomplex-variable finite element method, ZFEM, in that the global hypercomplex system of FE equations is not assembled nor solved. Instead, the displacement field is computed using a traditional, real-valued finite element method, and the numerical derivative of the stiffness matrix at the element level is only computed for a group of local, surrounding elements to the crack tip by using a Taylor series expansion based on complex numbers or dual numbers. The ERR is then determined as a sum of the element contributions. Derivatives of the ERR with respect to an arbitrary model parameter such as a crack extension, material property, or geometric feature are also available using a combination of the global and local methods, GL-ZFEM. Both L-ZFEM and GL-ZFEM were implemented into the commercial finite element software Abaqus through user defined element subroutines. Numerical results show that the ERR obtained by L-ZFEM has the same accuracy as that estimated through the global ZFEM or the J-integral methods but exhibits superior computational efficiency. © 2019 Elsevier Lt

MultiZ: A Library for Computation of High-order Derivatives Using Multicomplex or Multidual Numbers

Multicomplex and multidual numbers are two generalizations of complex numbers with multiple imaginary axes, useful for numerical computation of derivatives with machine precision. The similarities between multicomplex and multidual algebras allowed us to create a unified library to use either one for sensitivity analysis. This library can be used to compute arbitrary order derivates of functions of a single variable or multiple variables. The storage of matrix representations of multicomplex and multidual numbers is avoided using a combination of one-dimensional resizable arrays and an indexation method based on binary bitwise operations. To provide high computational efficiency and low memory usage, the multiplication of hypercomplex numbers up to sixth order is carried out using a hard-coded algorithm. For higher hypercomplex orders, the library uses by default a multiplication method based on binary bitwise operations. The computation of algebraic and transcendental functions is achieved using a Taylor series approximation. Fortran and Python versions were developed, and extensions to other languages are self-evident. © 2020 ACM

Sensitivity analysis for radiofrequency induced thermal therapies using the complex finite element method

In radiofrequency induced thermal procedures for cancer treatment, the temperature of the cancerous tissue is raised over therapeutic values while maintaining the temperature of the surrounding tissue at normal levels. In order to control these temperature levels during a thermal therapy, it is important to predict the temperature distribution over the region of interest and analyze how the variations of the different parameters can affect the temperature in the healthy and damaged tissue. This paper proposes a sensitivity analysis of the radiofrequency induced thermal procedures using the complex Taylor series expansion (CTSE) finite element method (ZFEM), which is more accurate and robust compared to the finite difference method. The radiofrequency induced thermal procedure is modeled by the bioheat and the Joule heating equations. Both equations are coupled and solved using complex-variable finite element analysis. As a result, the temperature sensitivity with respect to any material property or boundary condition involved in the process can be calculated using CTSE. Two thermal therapeutical examples, hyperthermia and ablation induced by radio frequency, are presented to illustrate the capabilities and accuracy of the method. Relative sensitivities of the temperature were computed for a broad range of parameters involved in the radiofrequency induced thermal process using ZFEM. The major feature of the method is that it enables a comprehensive evaluation of the problem sensitivities, including both model parameters and boundary conditions. The accuracy and efficiency of the method was shown to be superior to the finite difference method. The computing time of a complex finite element analysis is about 1.6 times the computing time of real finite element analysis; significantly lower than the 2 times of forward/backward finite differencing or 3 times of central differencing. It was found that the radiofrequency hyperthermia procedure is very sensitive to the electric field and temperature boundary conditions. In the case of the radiofrequency ablation procedure, the cooling temperature of the electrodes has the highest liver/tumor temperature sensitivity. Also, thermal and electrical conductivities of the healthy tissue were the properties with the highest temperature sensitivities. The result of the sensitive analysis can be used to design very robust and safe medical procedures as well as to plan specific patient procedures