Development and Transfer of Technological Pedagogical Content Knowledge (TPACK) of Special Education Teachers

This dissertation presents findings of three studies investigating the development and transfer of TPACK of pre-service and in-service elementary school special education teachers. The dissertation is presented in a non-traditional format including an introduction, three manuscripts submitted for journal publication, and a summary chapter. The purpose of the first study was to analyze development of TPACK of pre-service elementary special education teachers enrolled in a graduate level pedagogy course Integrating Technology in Mathematics and Science Instruction in Special Education and Inclusive Classrooms in a New York City public college. The study’s research question was to find out whether the TPACK- based course affects TPACK and basic TPACK domains of pre-service special education teachers’ knowledge: TK – technological knowledge, PK – pedagogical knowledge, and CK – content knowledge. The paired sample t-test indicated significant gains in teachers’ TPACK, however there were no significant changes in PK, TK and CK. The first study raised questions of whether the TPACK basic domains are independent of the TPACK domain. The purpose of the second study was to investigate the question raised in the first study i.e., whether TK, PK, and CK are independent constructs in the TPACK framework and to develop instruments for assessing the basic domains of the TPACK. Exploratory and confirmatory factor analyses suggested that the TPACK construct is independent from TK, PK, and CK. Multiple linear regression showed that TK, PK and CK are not predictors of the TPACK for this population. The purpose of the third study was to analyze TPACK development and a learning trajectory of a single pre-service elementary special education teacher and TPACK transfer from this course to the teaching during the induction to teaching year. It was noted that the graduate pedagogy course played a critical role in developing pre-service teacher’s TPACK. The study suggested several internal (teacher’s attitude towards using technology and preparedness – teacher’s comfort with using technology) and external (access to technology and school support) factors affecting transfer of teacher’s TPACK from her pre-service to in-service teaching experience

Compressive Sensing of Signals Generated in Plastic Scintillators in a Novel J-PET Instrument

The J-PET scanner, which allows for single bed imaging of the whole human body, is currently under development at the Jagiellonian University. The dis- cussed detector offers improvement of the Time of Flight (TOF) resolution due to the use of fast plastic scintillators and dedicated electronics allowing for sam- pling in the voltage domain of signals with durations of few nanoseconds. In this paper we show that recovery of the whole signal, based on only a few samples, is possible. In order to do that, we incorporate the training signals into the Tikhonov regularization framework and we perform the Principal Component Analysis decomposition, which is well known for its compaction properties. The method yields a simple closed form analytical solution that does not require iter- ative processing. Moreover, from the Bayes theory the properties of regularized solution, especially its covariance matrix, may be easily derived. This is the key to introduce and prove the formula for calculations of the signal recovery error. In this paper we show that an average recovery error is approximately inversely proportional to the number of acquired samples

Application of the Compress Sensing Theory for Improvement of the TOF Resolution in a Novel J-PET Instrument

Nowadays, in Positron Emission Tomography (PET) systems, a Time of Flight information is used to improve the image reconstruction process. In Time of Flight PET (TOF-PET), fast detectors are able to measure the difference in the arrival time of the two gamma rays, with the precision enabling to shorten significantly a range along the line-of-response (LOR) where the annihilation occurred. In the new concept, called J-PET scanner, gamma rays are detected in plastic scintillators. In a single strip of J-PET system, time values are obtained by probing signals in the amplitude domain. Owing to Compress Sensing theory, information about the shape and amplitude of the signals is recovered. In this paper we demonstrate that based on the acquired signals parameters, a better signal normalization may be provided in order to improve the TOF resolution. The procedure was tested using large sample of data registered by a dedicated detection setup enabling sampling of signals with 50 ps intervals. Experimental setup provided irradiation of a chosen position in the plastic scintillator strip with annihilation gamma quanta

Novel method for hit-position reconstruction using voltage signals in plastic scintillators and its application to Positron Emission Tomography

Currently inorganic scintillator detectors are used in all commercial Time of Flight Positron Emission Tomograph (TOF-PET) devices. The J-PET collaboration investigates a possibility of construction of a PET scanner from plastic scintillators which would allow for single bed imaging of the whole human body. This paper describes a novel method of hit-position reconstruction based on sampled signals and an example of an application of the method for a single module with a 30 cm long plastic strip, read out on both ends by Hamamatsu R4998 photomultipliers. The sampling scheme to generate a vector with samples of a PET event waveform with respect to four user-defined amplitudes is introduced. The experimental setup provides irradiation of a chosen position in the plastic scintillator strip with an annihilation gamma quanta of energy 511~keV. The statistical test for a multivariate normal (MVN) distribution of measured vectors at a given position is developed, and it is shown that signals sampled at four thresholds in a voltage domain are approximately normally distributed variables. With the presented method of a vector analysis made out of waveform samples acquired with four thresholds, we obtain a spatial resolution of about 1 cm and a timing resolution of about 80 p

The ATLAS SCT grounding and shielding concept and implementation

This paper presents a complete description of Virgo, the French-Italian gravitational wave detector. The detector, built at Cascina, near Pisa (Italy), is a very large Michelson interferometer, with 3 km-long arms. In this paper, following a presentation of the physics requirements, leading to the specifications for the construction of the detector, a detailed description of all its different elements is given. These include civil engineering infrastructures, a huge ultra-high vacuum (UHV) chamber (about 6000 cubic metres), all of the optical components, including high quality mirrors and their seismic isolating suspensions, all of the electronics required to control the interferometer and for signal detection. The expected performances of these different elements are given, leading to an overall sensitivity curve as a function of the incoming gravitational wave frequency. This description represents the detector as built and used in the first data-taking runs. Improvements in different parts have been and continue to be performed, leading to better sensitivities. These will be detailed in a forthcoming paper

Thin-film silicon detectors for particle detection

Integrated particle sensors have been developed using thin-film on ASIC technology. For this purpose, hydrogenated amorphous silicon diodes, in various configurations, have been optimized for particle detection. These devices were first deposited on glass substrates to optimize the material properties and the dark current of very thick diodes (with thickness up to 50 μm). Corresponding diodes were later directly deposited on CMOS readout chips. These integrated particle sensors have been characterized using light pulse illumination and beta particle irradiation from 63Ni and 90Sr sources. Direct detection of single low- and high-energy beta particles have been demonstrated. The application of this new integrated particle sensor concept for medical imaging is also discussed

Analogue read-out chip for Si strip detector modules for LHC experiments

We present a 128-channel analogue front-end chip SCTA128 for readout of silicon strip detectors employed in the inner tracking detectors of LHC experiments. The architecture of the chip and critical design issues are discussed. The performance of the chip has been evaluated in detail in bench tests and is presented in the paper. The chip is used to read out prototype analogue modules compatible in size, functionality and performance with the ATLAS SCT base line modules. Several full size detector modules equipped with SCTA128 chips have been built and tested successfully in the lab with E particles as well as in beam tests