Motivation can be identified as a dimension that determines learning success and causes the high dropout rate among online learners, especially in complex e-learning environments. It is argued that ...these learning environments represent a new challenge to cognitive load researchers to investigate the motivational effects of instructional conditions and help instructional designers to predict which instructional configurations will maximize learning and transfer. Consistent with the efficiency perspective introduced by Paas and Van Merriënboer (1993), an alternative motivational perspective of the relation between mental effort and performance is presented. We propose a procedure to compute and visualize the differential effects of instructional conditions on learner motivation, and illustrate this procedure on the basis of an existing data set. Theoretical and practical implications of the motivational perspective are discussed.
This article reports experimental work comparing
exploration and worked-examples practice in learning to use a
database program. Exploration practice is based on discovery
learning principles, ...whereas worked-examples practice arose from the
development of cognitive load theory. Exploration practice was
expected to place a considerable load on working memory, whereas a
heavy use of worked examples was hypothesized to lead to more
effective processing by reducing extraneous mental load. Students
with no previous domain familiarity with databases were found to
substantially benefit from worked examples in comparison to
exploration. However, if students had previous familiarity with the
database domain, the type of practice made no significant difference
to their learning because the exploration students were able to draw
on existing, well-developed domain schemas to guide their
exploration.
Detectors manufactured on p-type silicon material are known to have significant advantages in very harsh radiation environment over n-type detectors, traditionally used in High Energy Physics ...experiments for particle tracking. In p-type (n+ segmentation on p substrate) position-sensitive strip detectors, however, the fixed oxide charge in the silicon dioxide is positive and, thus, causes electron accumulation at the Si/SiO2 interface. As a result, unless appropriate interstrip isolation is applied, the n-type strips are short-circuited. Widely adopted methods to terminate surface electron accumulation are segmented p-stop or p-spray field implantations. A different approach to overcome the near-surface electron accumulation at the interface of silicon dioxide and p-type silicon is to deposit a thin film field insulator with negative oxide charge. We have processed silicon strip detectors on p-type Magnetic Czochralski silicon (MCz-Si) substrates with aluminum oxide (Al2O3) thin film insulator, grown with Atomic Layer Deposition (ALD) method. The electrical characterization by current–voltage and capacitance−voltage measurement shows reliable performance of the aluminum oxide. The final proof of concept was obtained at the test beam with 200GeV/c muons. For the non-irradiated detector the charge collection efficiency (CCE) was nearly 100% with a signal-to-noise ratio (S/N) of about 40, whereas for the 2×1015neq/cm2 proton irradiated detector the CCE was 35%, when the sensor was biased at 500V. These results are comparable with the results from p-type detectors with the p-spray and p-stop interstrip isolation techniques. In addition, interestingly, when the aluminum oxide was irradiated with Co-60 gamma-rays, an accumulation of negative fixed oxide charge in the oxide was observed.
Research on Cognitive Load Theory has shown that measures of cognitive load can reveal important information about the cognitive consequences of instructional conditions that is not necessarily ...reflected by traditional performance-based measures. Although, the individual measures of cognitive load can be considered important to determine the power of different instructional conditions, a meaningful interpretation of a certain level of cognitive load can only be given in the context of its associated performance level, and vice versa. This was recognized by Paas and Van Merriënboer (1993) who developed a 2-dimensional computational approach to combine measures of test performance with measures of the associated mental effort in order to compare the 'mental efficiency' of instructional conditions. In this approach, high task performance associated with low effort is termed high instructional efficiency, whereas low task performance with high effort is termed low instructional efficiency. Here we explore the utility of employing multi-dimensional approaches, in particular two 2-dimensional efficiency measures and a new 3-dimensional approach, which combines the measures of learning effort, test effort and test performance. Each of these approaches with their associated insights and analyses may be useful for instructional researchers, e.g. as diagnostic instruments to identify different aspects of efficient or inefficient instructional conditions and can be implemented in a broad range of learning environments, including electronic environments, possibly enabling more effective learning-task selection.
Recent results of CERN RD39 collaboration on the development of radiation hard Si detectors operated at low to cryogenic temperatures will be presented in this paper. It has been found, in ...comparisons of results of simulation and charge collection data of pad and strip detectors, the charge-injected-diode (CID) operation mode of Si detectors reduces the free carrier trapping, resulting in a much higher charge collection at the SLHC fluence than that in a standard Si detector. The reduction in free carrier trapping by almost a factor of 3 is due to the fact that the CID mode pre-fills the traps, making them neutral and not active in trapping of particle-induced free carriers (signal). It has been found that, electron traps can be pre-filled by injection of electrons from the n+ contact. The CID mode of detector operation can be achieved by a modestly low temperature of ≤−40°C and a operation bias of <600V. Results of one CID detector application as LHC beam-loss-monitor (BLM) will be presented. Non-irradiated Si detectors has been shown, with tests by laser using our cryogenic transient-current-technique (TCT), to work quite well at LHe temperature (4K), which are very stable with no polarization and good charge collection efficiency.
In this article, we discuss cognitive load measurement techniques with regard to their contribution to cognitive load theory (CLT). CLT is concerned with the design of instructional methods that ...efficiently use people's limited cognitive processing capacity to apply acquired knowledge and skills to new situations (i.e., transfer). CLT is based on a cognitive architecture that consists of a limited working memory with partly independent processing units for visual and auditory information, which interacts with an unlimited long-term memory. These structures and functions of human cognitive architecture have been used to design a variety of novel efficient instructional methods. The associated research has shown that measures of cognitive load can reveal important information for CLT that is not necessarily reflected by traditional performance-based measures. Particularly, the combination of performance and cognitive load measures has been identified to constitute a reliable estimate of the mental efficiency of instructional methods. The discussion of previously used cognitive load measurement techniques and their role in the advancement of CLT is followed by a discussion of aspects of CLT that may benefit by measurement of cognitive load. Within the cognitive load framework, we also discuss some promising new techniques.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Tracking detectors for future high-luminosity particle physics experiments have to be simultaneously radiation hard and cost efficient. This paper describes processing and characterization of Formula ...Omitted (n-type silicon bulk) detectors made of high-resistivity Magnetic Czochralski silicon (MCz-Si) substrates with 6-inch wafer diameter. The processing was carried out on a line used for large-scale production of sensors using standard fabrication methods, such as implanting polysilicon resistors to bias individual sensor strips. Special care was taken to avoid the creation of Thermal Donors (TD) during processing. The sensors have a full depletion voltage of 120-150 V which are uniform over the investigated sensors. All of the leakage current densities were below Formula Omitted at 200 V bias voltage. A strip sensor with 768 channels was attached to readout electronics and tested in particle beam with a data acquisition (DAQ) similar to the system used by the CMS experiment at the CERN LHC. The test beam results show a signal-to-noise ratio greater than 40 for the test beam sensor. The results demonstrate that MCz-Si detectors can reliably be manufactured in the industrial scale semiconductor process.
Magnetic Czochralski silicon as detector material Härkönen, J.; Tuovinen, E.; Luukka, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2007, Letnik:
579, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The Czochralski silicon (Cz-Si) has intrinsically high oxygen concentration. Therefore Cz-Si is considered as a promising material for the tracking systems in future very high luminosity colliders. ...In this contribution a brief overview of the Czochralski crystal growth is given. The fabrication process issues of Cz-Si are discussed and the formation of thermal donors is especially emphasized. N
+/p
−/p
+ and p
+/n
−/n
+ detectors have been processed on magnetic Czochralski (MCz-Si) wafers. We show measurement data of AC-coupled strip detectors and single pad detectors as well as experimental results of intentional TD doping. Data of spatial homogeneity of electrical properties, full depletion voltage and leakage current, is shown and n and p-type devices are compared. Our results show that it is possible to manufacture high quality n
+/p
−/p
+ and p
+/n
−/n
+ particle detectors from high-resistivity Cz-Si.
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