As computational thinking (CT) is being embraced by educational systems worldwide, researchers and teachers have posed important questions such as “what to teach” and “what can be learned.” These ...questions are universally crucial to the learning of all subjects. Nevertheless, there is no up-to-date, systematic overview of CT education for K-9 students that attempt to provide answers to these crucial questions. Thus, this systematic review presents a synthesis of 55 empirical studies, providing evidence of the development of computational thinking through programming in Scratch, one of the most popular visual block programming languages in schools. The purpose of this review is to systematically examine the CT skills that can be obtained through Scratch in K-9 based on empirical evidence. This systematic review has adopted Brennan and Resnick's (2012) framework as the basis for defining and identifying the expected CT skills in K-9. The major findings entail what computational thinking skills students in K-9 can learn through Scratch in relation to the framework mentioned above, taking the progression of learning into account. Additional CT skills that are not captured by the framework were identified including input/output, reading, interpreting and communicating code, using multimodal media, predictive thinking, and human-computer interaction. These additional CT skills are not currently presented in Brennan and Resnick's (2012) framework and can be considered as possible supplements to their framework. Furthermore, the paper discusses the difficulties regarding assessment and the progression of the identified skills, as well as problems with study designs. Finally, the paper sets out suggestions for future studies based on the current research gaps.
•The paper identified computational thinking skills that can be obtained through Scratch in compulsory education.•The paper presented a quantitative analysis of the methodology of the empirical studies.•The paper described the learning challenges and difficulties associated with the identified computational thinking skills.•The paper provided an overview of the progression of the computational thinking skills according to the learners' ages.•The paper revealed some problems in scientific reporting.
Owing to the breakthrough of artificial meta-materials, the emergence and evolution of reconfigurable intelligent surface (RIS) have drawn a novel blueprint for the development of the ...sixth-generation (6G) wireless networks, through the creation of smart radio environment to meet the requirement of ubiquitous connectivity. Meanwhile, the vision for the 6G illuminates the integration of sensing and communication, bringing out a demand for both high-quality communication and high-precision localization. Therefore, regarding the future wireless localization, the potential of RIS to tag the signals provides additional degrees of freedom. To this end, to fulfil the increasing demands for positioning, RIS has drawn a growing amount of research both from academia and industry. In this paper, we first introduce the emerging investigations and development of RIS, and we give a concise summary of the localization principles. Then we explain the potential of RIS in localization, and provide a comprehensive survey of the current state of research on RIS-assisted localization. Finally, we discuss the most significant research challenges to tackle for RIS-aided localization in the future.
Teachers around the world have started teaching programming at the K-9 level, some due to the formal introduction of programming in the national curriculum, others without such pressure and on their ...own initiative. In this study, we attempted to understand which skills - both CT-related and general - are developed among pupils in the process of working with programming in schools. To do so, we interviewed 19 Swedish teachers who had been teaching programming for a couple of years on their own initiative. The teachers were selected based on their experience in teaching programming. Our thematic analysis of these interviews shed light on what skills teachers perceive pupils develop when programming. This led us to identify three themes related to CT skills and five themes related to general skills. The CT skills identified corresponded well with and were thus thematically structured according to the dimensions of CT proposed in the framework of Brennan and Resnick, namely computational concepts, computational practices and computational perspectives. In addition to the CT skills, our thematic analysis also resulted in the identification of general skills related to digital competency and 21st century skills, namely cognitive skills and attitudes, language skills, collaborative skills and attitudes and creative problem-solving skills and attitudes.
Problem and goal. Computational thinking has been introduced in many countries around the world and teachers are working intensely to incorporate programming activities in the classroom. However, ...teachers are faced with several challenges due to the fact that there is still little research conducted focusing on programming education for younger children, that programming didactics is a rather new phenomenon for the K-9 educational system, and that K-9 teachers have little training with regards to programming. In Sweden for instance, programming has been introduced in several subjects and not as a subject in its own, which create a pressure on teachers to utilize programming as an instrument to teach and enhance learning of different subjects such as mathematics. Methodology. In this paper, we report on a larger lesson study conducted in a primary school (sixth grade) in Sweden with a total of 155 participating pupils. The aim of the lesson was to study whether the visual programming languages, Scratch , in particular, can be used to teach computational thinking, mathematics and social science in an interdisciplinary way. Results. Thus, the paper more specifically presents findings related to: 1) reflections of the use of lesson study methodology to develop programming education; 2) how programming can be utilized as an instrument to teach mathematics as well as social sciences in an interdisciplinary way; and 3) the didactical strategies employed by the teachers. Conclusion. The evidence from this study suggests that the interdisciplinary character of the lesson which incorporates learning goals of mathematics, social science and programming was highly beneficial. The pupils gained a better understanding of learning material by drawing, digitalizing and animating their ideas in Scratch .
In this contribution, a practical reconfigurable intelligent surface (RIS)-assisted multiple-input multiple-output (MIMO) system is presented to improve the performance and spectral efficiency (SE) ...of state-of-the-art RIS-assisted spatial modulation systems by introducing phase offsets on the RIS and transmitter. As opposed to conventional RIS-assisted spatial modulation schemes, the proposed RIS-assisted generalized spatial modulation with phase offset (RIS-GSM-P) scheme activates an arbitrary number of transmit antennas to form a wider variety of transmit antenna combinations (TAC) for improving SE. Depending on whether the direct path is available or not, two phase offset schemes are conceived to enhance the beamforming of the RIS and to widen the channel difference between TACs. Finally, a unified framework for the theoretical bit error rate upper bound of the proposed RIS-GSM-P scheme is presented, which is also compatible with several conventional RIS-assisted transmission schemes. Furthermore, a low-complexity detector is provided to reduce the detection complexity. Monte Carlo simulation results are provided to demonstrate the effectiveness of the proposed schemes and to validate our theoretical analysis.
Blast furnace (BF) ironmaking is the predominating process for producing hot metal (HM). It consumes huge quantities of carbonaceous fuel materials and leads to massive CO2 emissions. The injection ...of coke oven gas (COG) into the BF is considered a promising solution. It recovers the COG that is a kind of off-gas in the steelwork, and reuses the COG as an H2-intensive fuel in the BF to partially replace the use of carbonaceous fuel materials. However, thus far, the technology is not widely adopted, mainly due to the lack of understanding regarding the effects of key operational parameters of COG injection on BF performance. In addition, the coupling effect of COG injection and BF operation particularly the control at furnace top is not clear, leading to the low utilization efficiency. In this work, a continuum-based BF process model is developed and validated to consider the injection of COG into a commercial scale BF through the tuyere. The model is validated by comparing the calculated key performance indicators with those measured in production. The impact of COG injection rate is studied and its coupling effects with top burden distribution have also been clarified. The simulation results show that an increased COG injection rate leads to improved BF performance, in terms of increased productivity and decreased consumption of carbonaceous fuel materials. However, the utilization efficiency of COG and the replacement ratio of carbonaceous fuel materials by COG is decreased. An optimum top burden distribution can be identified, which can improve the utilization efficiency of injected COG and achieve a relatively high replacement ratio. The findings from this work should be useful to guide production of BF with H2-intensive fuel injection, which helps to save the use of carbonaceous fuel materials and reduce CO2 emission.
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•A BF model is developed that can consider simultaneous injection of various fuels.•Effects of COG injection rate on BF are studied based on a commercial scale BF.•Coupling effects of COG injection rate and furnace top control on the BF is clarified.•Optimum top burden distribution is identified to improve COG utilization efficiency.•Mechanism for key factors affecting utilization efficiency of injected COG is explained.
The shaft furnace based H2-intensive direct reduction process has the potential to realize “carbon neutrality” and can significantly reduce the CO2 emission, compared to the traditional blast furnace ...process. To date, no commercial-scale shaft furnace using H2 has been established, due to the lack of corresponding understanding. In this work, a continuum-based shaft furnace model is developed, which considers the multi-phase flows of gas and solid, heat and mass transfer as well as key chemical reactions in the direct reduction process. It is validated by comparing the simulated performance indicators with those measured in the plant. Using the model, the effects of the pressure at the cooling gas outlet have been studied. The results show that the pressure at the cooling gas outlet has a significant impact on in-furnace gas flow, which should be carefully controlled to separate the reducing and cooling gas effectively. As for the product, the carburization and metallization of direct reduced iron can also be optimized through proper control of the pressure at the cooling gas outlet. On this basis, under the same injection rate, the production using H2 is compared with the normal one using reformed natural gas, under their respectively optimized conditions. It is shown that the production with H2 delivers direct reduced iron with less carburization and metallization. Charging large-sized pellets into the furnace centre can solve the problems to a degree by improving the gas flow distribution in the reducing zone. This work should provide a deeper insight into the cleaner production of the shaft furnace based direct reduction process, particularly that operated with H2.
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Novel communication technology based on large intelligent surface (LIS), which manipulates the phase of the incident waves to enhance the communication quality, has been proposed as a promising ...candidate for future wireless communication systems and standards. In order to improve the spectral efficiency, the concept of LIS assisted communications has been introduced into the realm of index modulation (IM) recently. In this letter, a practical LIS based generalized spatial modulation (LIS-GSM) scheme is proposed by modulating the transmit signals through both transmitter and LIS jointly while designing the pattern of receive antennas in a more flexible way. Furthermore, a unified framework for the derivation of the theoretical average bit error rate (ABER) based on the maximum likelihood detector is also presented. Simulation results demonstrate that LIS-GSM is more robust in terms of ABER as well as receive antenna pattern compared with conventional LIS-SM.
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