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Contribution: This article features a systematic literature review with the objective of presenting a study that reflects the current scenario of research on the cognitive load theory (CLT) in the domain of teaching and learning computer programming. Background: Computer programming is a highly cognitive skill, requiring mastering multiple competencies, and recognized as being difficult to learn, for this reason, the cognitive load (CL) in the learner’s working memory emerged as an influential concept, making CLT one of the most common theories in computing education research. Research Questions: What are the approaches that relate CLT to teaching and learning computer programming? What CLT-related concepts are covered? What evidence is reported with respect to this context? Methodology: Following a formal protocol, a survey was performed for papers linking CLT to teaching and learning programming published between 2010 and 2020. The selection of papers was based on a set of criteria established to drive the selection process, including alignment with the research questions and paper quality assessment. Findings: The approaches applied in the papers are based on measuring the CL; through instructional design based on the development or use of resources or tools, a range of different pedagogy strategies and the CLT concepts. With respect to the concepts, the subjective measurement technique and worked example effect are the most commonly deployed. As far as the evidence reported, the better part is related to the worked example effect and measuring CLs. [ABSTRACT FROM AUTHOR]

Contributions: The underrepresentation of women in computer science (CS) majors has long been a focus of attention in many academic documents, the majority of them from the United States and Europe. There is, however, a lack of information about educational interventions (EIs) for women in computing in Latin America. The contribution of this article is to cover this gap and describe what researchers in Latin American countries have been publishing about the recruitment and retention of women in the CS field. Background: Many EIs targeting female students at different educational levels—K-12, undergraduate, and graduate—have been undertaken to increase the participation of women in computing in Latin America. However, descriptions of these activities rarely are included in international academic databases. Research Questions: This literature mapping addresses two main research questions (RQ) about the topic of women in computing in academic publications in Latin American countries: RQ1) what are the characteristics of the publications about women in computing in Latin America? and RQ2) what are the published interventions to recruit and retain women in computing in Latin America? To answer RQ1, six subquestions were created covering year, language, country of origin, document type, and professional track. Furthermore, for RQ2, two subquestions were created involving educational level and the use of software development with a female theme. Methodology: This investigation used the systematic literature mapping process. To achieve a broad coverage of papers, the following sources were included: Scopus, Web of Science, Google Scholar, EBSCO, the proceedings of the Latin American Women in Computing Conference (LAWCC), and those of the Women in Technology (WIT) workshop colocated with the annual conference of the Brazilian Computer Society (SBC). The included papers were published in the last decade (2010–2020) and written in English, Portuguese, or Spanish. Findings: The literature mapping encompasses 197 academic documents, 48.2% of which were written in Portuguese, 28.7% in English, and 23.1% in Spanish. The papers originated from 15 of the 20 Latin American countries. Brazil and Costa Rica have the highest number of publications overall. The documents describe initiatives to increase the participation of women in computing majors that cover the entire educational spectrum, from K-12 to graduate programs, but papers targeting populations in higher education have started to appear recently. [ABSTRACT FROM AUTHOR]

Scholars have suggested that design thinking (DT) should form an integral part of the new product development (NPD) process. However, the contribution of DT to NPD over the past years is yet to be synthesized. In this article, we develop a conceptual framework categorizing how DT contributes to NPD, and present a map to visualize how research in the area of DT in NPD has evolved over the past 20 years. A systematic analysis of 89 journal papers published between 2000 and 2020 helped to generate a conceptual framework, which provides a typology for discussing the growing state of the art of DT in NPD. The study enhances the academic debate by providing a holistic perspective on how DT contributes to the NPD ecosystem and offers directions for future research for the next 20 years. [ABSTRACT FROM AUTHOR]

Many modern navigation systems and map-based services do not only provide the fastest route from a source location $s$ s to a target location $t$ t but also provide a few alternative routes to the users as more options to choose from. Consequently, computing alternative paths has received significant research attention. However, it is unclear which of the existing approaches generates alternative routes of better quality because the quality of these alternatives is mostly subjective. Motivated by this, in this paper, we present a user study conducted on the road networks of Melbourne, Dhaka and Copenhagen that compares the quality (as perceived by the users) of the alternative routes generated by four of the most popular existing approaches including the routes provided by Google Maps. We also present a web-based demo system that can be accessed using any internet-enabled device and allows users to see the alternative routes generated by the four approaches for any pair of selected source and target. We report the average ratings received by the four approaches and our statistical analysis shows that there is no credible evidence that the four approaches receive different ratings on average. We also discuss the limitations of this user study and recommend the readers to interpret these results with caution because certain factors may have affected the participants’ ratings. [ABSTRACT FROM AUTHOR]

Background: More than 30 years ago, Harmon distinguished developmental research articles (RAs), which propose a solution to a problem, from experimental RAs, but the developmental format has received little attention. Literature review: Genre analysis of RAs has been largely restricted to articles following the standard experimental/Introduction, Methods, Results, Discussion (IMRD) format, thereby excluding many developmental engineering articles. Recently, a textbook proposed Introduction, Process, Testing, Conclusion (IPTC) as a prototypical format for electrical engineering RAs, but this format has not yet been demonstrated from a corpus. Research questions: 1. What is the macrostructure of electrical engineering RAs? 2. What are the characteristic features of each division of electrical engineering RAs? Methodology: Section headings, wordcount, and notable features were analyzed for 75 RAs from 15 electrical engineering journals and compared with both IPTC and Harmon's developmental structure. Results: Only one article, a case study, followed IMRD. Sixty-seven developmental RAs followed the IPTC format. These are distinguished by the second division (P), where the new solution is described, written in extended style, comprising several sections with headings specific to the research. A paragraph at the end of the Introduction describing the organization of the paper, the location of the theoretical framework and testing methods, and a ubiquitous Conclusion also differ from IMRD. Seven developmental RAs exhibited a hybrid format with the well-known IMRD section headings superimposed on an IPTC structure. Conclusions: Most electrical engineering articles are developmental and follow IPTC format. This can inform future genre analysis research and has pedagogical implications for teaching engineering writing. [ABSTRACT FROM AUTHOR]

The term “business incubator” (BI) has become an accepted neologism among academics, practitioners, and policymakers. This is despite the lack of an agreed definition amongst scholars of what exactly constitutes a BI. Using a systematic literature review methodology, we identify and analyze definitions of BIs used in published academic research papers and practice papers over a 35-year period. In this article, we undertake a thematic analysis, using the software package NVivo, of 82 academic and 14 practice definitions used in 61 publications. Our analysis shows that definitions of BIs are constructed around three core themes: the business incubation model; the purpose of the incubator; and the target of support provided by the incubator. By identifying both consistencies and inconsistencies in existing definitions, we provide a more nuanced understanding of the heterogeneity that underlies the organizational form referred to as a BI. We conclude by proposing an agenda for further research. [ABSTRACT FROM AUTHOR]

A common method for reading information stored in DNA molecules is shotgun sequencing. This method outputs a histogram of the frequencies of all the molecules’ substrings of a given length $\ell $. To protect against noisy readings, the rank-modulation scheme encodes the information in the relative ranking of the substring frequencies, instead of their absolute values. However, the best rank-modulation codes for shotgun sequencing have low rates which are asymptotically vanishing. In this paper we propose new constructions of rank-modulation codes for shotgun sequencing. The first code construction is systematic, allowing the user to arbitrarily set the frequencies of a large subset of the substrings, which the encoder then completes to a permutation that may be realized by a DNA molecule. The construction is then improved by allowing the user to set the frequencies of additional substrings, at the cost of imposing constraints on the frequencies. The resulting codes have higher, non-vanishing rates, compared with previously known codes. As an example, for histograms of substrings of length $\ell =2$ , and an alphabet of size 4 (as in DNA molecules), we are able to construct a code with rate $\approx 0.909$ , whereas previously, the best construction resulted in a code with rate $\approx 0.654$. Additionally, the encoded information in our construction may be written to shorter DNA molecules than possible before. We also prove that the systematic codes constructed in this paper are the largest possible among all systematic codes. [ABSTRACT FROM AUTHOR]

In this article, with the increased disruptions faced by businesses and the occurrence of natural disasters in the world, supply chain resilience remains a major challenge especially for small- and medium-sized enterprises (SMEs). Despite the relevance of SMEs to the economy, there is limited scholarly work on resilience practices in SMEs and a limited understanding of how SMEs can achieve resilience. To understand the role of supply chain resilience in SMEs, we undertake a systematic literature review (SLR), which results in the identification and analysis of 101 journal articles, published between 2006 and 2019, on SME supply chain resilience. Our analysis into SME supply chain resilience highlights four focal areas: 1) the role of collaboration and culture; 2) the role of SMEs’ capabilities; 3) the role of Information Systems; and (4) the role of cost and financing. Our SLR investigation identifies future research directions and focal areas tailored to SMEs to help them to assess and develop their supply chain resilience. [ABSTRACT FROM AUTHOR]

Firms engaged in university–industry collaboration (UIC) desire to advance knowledge and new technologies with their academic partners, however the performance of knowledge creation and transfer is greatly affected by complementarity and compatibility between the firm and academic institute. In practice, many firms assess the appropriateness of academic partners using a broad range of criteria, with high subjectivity. This paper therefore seeks to address this challenge by introducing a systematic approach to help firms determine the appropriateness of academic partners, represented as “matching quality” in this paper. Three facets of matching quality are examined: complementarity of research ability, compatibility in business mindset, and compatibility in relationships. This paper proposes a framework and model for assessing matching quality, along with a case study to demonstrate how the proposed model works. [ABSTRACT FROM AUTHOR]

It is possible to launch undetectable load-redistribution (LR) attacks against power systems even in systems with protection schemes. Therefore, it is imperative to detect LR attacks in power systems and establish corrective actions to provide secure dispatch points. This paper develops a systematic real-time LR threat analysis (RTLRTA) tool to flag LR attacks and identify all affected transmission assets. Since attackers might introduce some forms of random strategies to create LR attacks, we introduce different optimization models to generate random LR attacks to determine accurate thresholds for our detection index and test the tool’s functionality. Additionally, based on an estimation for the actual loads in the post-attack stage, we design a set of physical line flow security constraints (PLFSCs) that can be added to the existing security-constrained economic dispatch (SCED) models. This leads to appropriate responses to the identified LR attacks and provides secure dispatch points. We generate multiple scenarios of LR attacks and random errors for different target lines in the 2383-bus Polish test system to validate our proposed methods’ accuracy and functionality in detecting LR attacks and responding to them. [ABSTRACT FROM AUTHOR]

Over the past 20 years, the rapid integration of renewable energy has resulted in electricity markets that are increasingly complex, interconnected, and uncertain. Similar to the banking system's financial crisis in 2008 due to chained reactions, severe financial losses due to uncertainty at a large renewable farm could induce significant financial losses at other market participants. The spread of such financial shocks can be worsened by centralized market clearing, and systemic risks consequently germinate in electricity market operations. Therefore, our previous work has compared systemic risk with systematic risk in the electricity market with uncertainties. However, the scope of our previous work has been limited to risk indices. This paper aims to broaden the study by proposing the theoretical foundation of systemic risk analysis in electricity markets with uncertainties. First, an electricity market financial network is defined to describe the cash inflow/outflow of all participants, and the financial contagion is employed to model the interlinks between different entities. Then, two financial properties, financial resilience and financial reliability, are proposed to evaluate the systemic risk in market settlements with uncertainties. Finally, the proposed theoretical foundation of systemic risk is demonstrated on the Texas synthetic 2000-bus system with 70% renewable penetration. [ABSTRACT FROM AUTHOR]

The prefixed Varshamov-Tenengolts (VT) codes, which are subsets of VT codes with predetermined prefixes, can be used for error correction over segmented edit channels. In this paper, we investigate the construction and analysis of this class of codes. First, we derive upper bounds on the size of zero-error codes for segmented edit channels with segment-by-segment decoding. Second, we establish a one-to-one correspondence between prefixed VT codes and Levenshtein codes. Based on this relation, we can obtain explicit formulas on the size of prefixed VT codes via the existing results on the size of Levenshtein codes. Third, we construct a new zero-error prefixed VT code and show that the size of the constructed code is strictly larger than that of the existing prefixed VT code for the segmented deletion channel. Finally, an efficient systematic encoding method of prefixed VT codes is proposed for the segmented edit channels. [ABSTRACT FROM AUTHOR]

To provide reliable transmissions with flexible rates for satellite communications, this paper presents a novel method of constructing multi-rate quasi-cyclic low-density parity-check (LDPC) codes. The basic idea is to generate low-rate codes from a high-rate mother code by combining shortening and extending, which ensures that the generated code family owns the same code length, in order to maintain the same frame structure. The code construction involves the design of base matrices and exponent matrices for the designed codes. A progressive row elimination and addition algorithm is proposed for designing the code base matrices from a high rate to low rates. This algorithm leads to the nested and systematic structure of the parity-check matrices, which are desirable for practical implementations of their encoders and decoders, while ensuring the optimal decoding thresholds. In addition, we construct a circulation coefficient matrix based on finite fields and select the optimal rows in this matrix to construct exponent matrices while considering of cycle structures. We demonstrate that the designed codes achieve better performance for all the code rates than the LDPC codes in DVB-S2X standards. In addition, the proposed codes do not exhibit error floors for their block error rates down to 10−5. [ABSTRACT FROM AUTHOR]

Functional and nonfunctional characteristics of software systems are defined by their architecture. Therefore, research streams such as Internet-of-Things (IoT) or component-based software engineering provide researchers and practitioners with construction guidelines for selected architectural characteristics. Current systems can be categorized in delivering services to the user and being engineered in a smart way. For example, services being provided by IoT-Systems must fulfill users’ goals in a highly dynamic and ad-hoc way. Consequently, this survey aims at answering various research questions regarding the methodical composition of system components and services. Furthermore, new research opportunities are sketched that should be tackled to make the scientific progress available to practitioners. Based on a systematic literature review from a software architecture point of view, in this paper we identify 75 primary studies for domain-specific IoT component composition approaches and architectures. Initial results show that current integration approaches mainly focus on performance evaluation of their integration solutions, which may be too narrow for fulfilling user goals by utilizing of IoT architectures. [ABSTRACT FROM AUTHOR]

The problem of computing the Hamming weight distribution of linear codes is considered in this paper. A novel method to enumerate all codewords up to a certain Hamming weight for binary linear block codes in general and in particular for the punctured, shortened, precoded polar codes is introduced. The proposed approach performs a recursive decomposition of the codes using construction X4 that is typically used to combine codes of different lengths. This allows to enumerate the low-weight codewords of the overall code as combinations of the low-weight codewords of the component codes. Numerical results show that the proposed approach can efficiently compute the exact partial weight distribution of the 5G New Radio punctured/shortened polar codes with CRC11 and pure polar codes. In the former and latter cases, the low-weight codeword number is up to 106 and 108, respectively. Besides, randomly punctured and shortened polar codes and randomly precoded polar codes are also considered. To the best of the authors’ knowledge, this is the first method able to solve these problems. [ABSTRACT FROM AUTHOR]

Contribution: This document presents a systematic bibliographic review that demonstrates the need to conduct research on how the user experience impacts the development of computational thinking. Background: In the field of computer science, computational thinking is defined as a method that enhances problem-solving skills, system design, and human behavior understanding. Over the last few decades, several tools have been proposed for the development of computational thinking skills; however, there is no area of study that evaluates the implications or the impact that these types of platforms have on users belonging to any knowledge area. Research Question: Do user interfaces influence the development of computational thinking skills? Methodology: To address this issue, a systematic review of the literature was conducted using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) methodology for analyzing and evaluating scientific publications. Findings: The results show that despite the dearth of literature on the subject, the specific design of a user interface has a significant impact on the development of computational thinking. Bearing the above in mind, it is necessary to conduct research that delves more deeply into the effects caused by the technologies that are used to develop computational thinking, this being a line of research that is worthy of consideration. [ABSTRACT FROM AUTHOR]

In ICISC-05, and in the ePrint 2010/287, Patarin claimed a lower bound on the number of $2 q$ tuples of $n$ -bit strings $(P_{1}, \ldots, P_{2q}) \in ({\{0,1\}}^{n})^{2q}$ satisfying $P_{2i - 1} \oplus P_{2i} = \lambda _{i}$ for $1 \leq i \leq q$ such that $P_{1}, P_{2}, \ldots $ , $P_{2q}$ are distinct and $\lambda _{i} \in {\{0,1\}} ^{n} \setminus \{0^{n}\}$. This result is known as Mirror theory and widely used in cryptography. It stands as a powerful tool to provide a high-security guarantee for many block cipher-(or even ideal permutation-) based designs. In particular, Mirror theory has a direct application in the security of XOR of block ciphers. Unfortunately, the proof of Mirror theory contains some unverifiable gaps and several mistakes. This paper provides a simple and verifiable proof of Mirror theory. [ABSTRACT FROM AUTHOR]

Constrained codes are used to prevent errors from occurring in various data storage and data transmission systems. They can help in increasing the storage density of magnetic storage devices, in managing the lifetime of solid-state storage devices, and in increasing the reliability of data transmission over wires. Over the years, designing practical (complexity-wise) capacity-achieving constrained codes has been an area of research gaining significant interest. We recently designed various constrained codes based on lexicographic indexing. We introduced binary symmetric lexicographically-ordered constrained (S-LOCO) codes, $q$ -ary asymmetric LOCO (QA-LOCO) codes, and a class of two-dimensional LOCO (TD-LOCO) codes. These families of codes achieve capacity with simple encoding and decoding, and they are easy to reconfigure. We demonstrated that these codes can contribute to notable density and lifetime gains in magnetic recording (MR) and Flash systems, and they find application in other systems too. In this paper, we generalize our work on LOCO codes by presenting a systematic method that guides the code designer to build any constrained code based on lexicographic indexing once the finite set of data patterns to forbid is known. In particular, we connect the set of forbidden patterns directly to the cardinality of the LOCO code and most importantly to the rule that uncovers the index associated with a LOCO codeword. By doing that, we reveal the secret arithmetic of patterns, and make the design of such constrained codes significantly easier. We give examples illustrating the method via codes based on lexicographic indexing from the literature. We then design optimal (rate-wise) constrained codes for the new two-dimensional magnetic recording (TDMR) technology. Over a practical TDMR model, we show notable performance gains as a result of solely applying the new codes. Moreover, we show how near-optimal constrained codes for TDMR can be designed and used to further reduce complexity and error propagation. All the newly introduced LOCO codes are designed using the proposed general method, and they inherit all the desirable properties in our previously designed LOCO codes. [ABSTRACT FROM AUTHOR]

Linear codes over $\mathbb {Z}_{p^{s}}$ of length $n$ are subgroups of $\mathbb {Z}_{p^{s}}^{n}$. These codes are also called $\mathbb {Z}_{p^{s}}$ -additive codes and can be seen as a generalization of linear codes over $\mathbb {Z}_{2}$ and $\mathbb {Z}_{4}$. A $\mathbb {Z}_{p^{s}}$ -linear code is a code over $\mathbb {Z}_{p}$ , not necessarily linear, which is the generalized Gray map image of a $\mathbb {Z}_{p^{s}}$ -additive code. In 2015, a systematic encoding was found for $\mathbb {Z}_{4}$ -linear codes. Moreover, an alternative permutation decoding method, which is suitable for any binary code (not necessarily linear) with a systematic encoding, was established. In this paper, we generalize these results by presenting a systematic encoding for any $\mathbb {Z}_{p^{s}}$ -linear code with $s\geq 2$ and $p$ prime. We also describe a permutation decoding method for any systematic code over $\mathbb {Z}_{p}$ , not necessarily linear, and show some examples of how to use this systematic encoding in this decoding method. [ABSTRACT FROM AUTHOR]

This paper presents the first systematic study of the zero-error capacity regions of noisy networks. First, we consider two simple such networks, each consisting of a stationary memoryless multiple access channel with two binary inputs and one discrete output. There are two users in each network. Each of the two users transmits a message through the network, and the sink(s) of the network can decode both messages with zero error. A graph is used to represent the distinguishability of the inputs of the channel, and a graph set is used to represent the distinguishability of the inputs of the network. We show that for two networks represented by the same graph set, their zero-error capacity regions are the same. We list all the possible graph sets for the two networks and determine the zero-error capacity regions for some of these graph sets. Based on this result, we explore a relation between graph theory and set theory, and then redefine the cancellative pair of families of subsets. We further extend the problem formulation to a general network called the parallel network, which may consist of more than one channel with multiple inputs and multiple outputs. [ABSTRACT FROM AUTHOR]

This paper investigates the problem of correcting multiple criss-cross insertions and deletions in arrays. More precisely, we study the unique recovery of $n \times n$ arrays affected by ${t}$ -criss-cross deletions defined as any combination of ${t_{\mathrm {r}}}$ row and ${t_{\mathrm {c}}}$ column deletions such that ${t_{\mathrm {r}}}+ {t_{\mathrm {c}}}= {t}$ for a given $t$. We show an equivalence between correcting ${t}$ -criss-cross deletions and ${t}$ -criss-cross insertions and show that a code correcting ${t}$ -criss-cross insertions/deletions has redundancy at least ${t} n + {t}\log n - \log ({t}!)$. Then, we present an existential construction of a ${t}$ -criss-cross insertion/deletion correcting code with redundancy bounded from above by ${t} n + \mathcal {O}({t}^{2} \log ^{2} n)$. The main ingredients of the presented code construction are systematic binary ${t}$ -deletion correcting codes and Gabidulin codes. The first ingredient helps locating the indices of the inserted/deleted rows and columns, thus transforming the insertion/deletion-correction problem into a row/column erasure-correction problem which is then solved using the second ingredient. [ABSTRACT FROM AUTHOR]

Some nonlinear codes, such as Kerdock and Preparata codes, can be represented as binary images under the Gray map of linear codes over rings. This paper introduces MAP decoding of Kerdock and Preparata codes by working with their quaternary representation (linear codes over $\mathbb {Z}_{4}$) with the complexity of $\mathcal {O}(N^{2}\log _{2} N)$ , where N is the code length in $\mathbb {Z}_{4}$. A sub-optimal bitwise APP decoder with good error-correcting performance and complexity of $\mathcal {O}(N\log _{2} N)$ that is constructed using the decoder lifting technique is also introduced. This APP decoder extends upon the original lifting decoder by working with likelihoods instead of hard decisions and is not limited to Kerdock and Preparata code families. Simulations show that our novel decoders significantly outperform several popular decoders in terms of error rate. [ABSTRACT FROM AUTHOR]

The problem of coding for informed receivers (IR) is considered, where a transmitter multicasts a bunch of messages to its associated receivers, each of which already has a subset of messages as side information. Which receiver has what side information is unknown to the transmitter. A family of polar codes for IR was proposed for binary-input channels in (Huang and Shieh, 2018), which was shown to provide excellent side information gain regardless of side information configuration and content. A trial extension of this scheme to high-order modulations, however, was unsatisfactory. In this paper, two families of systematic polar coded modulations for IR are proposed. In the first family, by building a connection between the message bits and modulated symbols under systematic polar codes, we leverage the bit assignments and labeling techniques such that receiver side information can be directly translated to a minimum distance gain. In the second family, a permutation operation is added before modulation such that the message bits can be properly reordered to further advance and balance the gains among different side information configurations. Simulations show that the proposed schemes provide large and balanced side information gains and significantly outperform the system directly adapted from (Huang and Shieh, 2018) onto high-order modulations. [ABSTRACT FROM AUTHOR]

This article aims to determine factors crucial for the performance of new ventures by performing a meta-analysis. It evaluates the performance of machine learning and statistical models by selecting 19 studies through preferred reporting items for systematic reviews and meta-analyses (PRISMA). The results obtained were graphically represented using forest plots. A subjective analysis of the studies revealed “business plan,” “market scope,” “team size,” “service timing,” “market growth,” and “age of the entrepreneur” as crucial factors for deciding the performance of the new ventures. In machine learning model-based studies, the combined model was found to be statistically significant. The variables, namely, “seed funding,” “funding rounds,” “location,” “social media presence,” “team size,” “number of founding members,” and “defunct date” affect the predictive capability of these models. The implications of this article can be applied by start-ups to reduce uncertainty and enhance performance. [ABSTRACT FROM AUTHOR]

Contribution: This article lends empirical evidence to this research area of factors influencing students’ choice of and success in science, technology, engineering, and mathematics (STEM). Background: Understanding these factors is crucial as it informs recruitment and support interventions provided to students and constitutes a premise to improving graduation rates. The social cognitive career theory (SCCT) was used as a theoretical framework to provide insight regarding factors influencing students’ choice of qualifications. Research Questions: What is the state of research on the factors influencing students’ choice of and success in STEM programmes? Which of these factors have interested most researchers? What research themes are covered in articles investigating these factors? Methodology: This study followed the general bibliometric analysis workflow—study design, data collection, data analysis, data visualization, and interpretation. Data collection followed the preferred reporting items for systematic review and metaanalysis (PRISMA) guidelines. From an initial set of 408 articles, 179 related to the theme and were published in the Web of Science between 2004 and 2020. These articles were analyzed using the standard bibliometric metrics. Findings: Findings indicate that this research field is still growing. Thirty-two factors were identified and rated based using an objective assessment criterion. In addition, a classification of the factors is presented based on the SCCT. This study provides a theoretical reference for improving success rates for STEM qualifications and better understanding the theme. The study proposes a research agenda of what future research in the field should focus on, based on current gaps. [ABSTRACT FROM AUTHOR]

For high-rate linear systematic maximum distance separable (MDS) codes, most early constructions could initially optimally repair all the systematic nodes but not all the parity nodes. Fortunately, this issue was first solved by Li et al. in (IEEE Trans. Inform. Theory, 64(9), 6257-6267, 2018), where a transformation that can convert any nonbinary MDS array code into another one with desired properties was proposed. However, the transformation does not work for binary MDS array codes. In this paper, we address this issue by proposing another generic transformation that can convert any $[n, k]$ binary MDS array code into a new one, which endows any $r=n-k\ge 2$ chosen nodes with optimal repair bandwidth and optimal rebuilding access properties, and at the same time, preserves the normalized repair bandwidth/rebuilding access for the remaining $k$ nodes under some conditions. As two immediate applications, we show that 1) by applying the transformation multiple times, any binary MDS array code can be converted into one with optimal rebuilding access for all nodes, 2) any binary MDS array code with optimal repair bandwidth or optimal rebuilding access for the systematic nodes can be converted into one with the corresponding optimality property for all nodes. [ABSTRACT FROM AUTHOR]

With ever more stringent requirements of cellular standards it is an ongoing challenge to find the optimal RF transmitter architecture. In recent years, the multiphase transmitter (MP TX) architecture has been introduced as a promising candidate. It features high power efficiency and avoids phase modulation which is critical for upconversion of ultra-wideband signals. In this brief, the problem of unwanted spectral emission, inherent in MP TX architectures, is compensated by a proper data delay. Such an approach is considered for the first time in the multiphase architecture and achieves a spectral improvement of up to 38 dB in adjacent channels and 24 dB at the receiver (RX) duplex distance for a new radio (NR) signal with 20 MHz bandwidth. With the proposed solution the MP TX architecture becomes a highly competitive candidate for wideband signals such as LTE, LTE-CA or NR signals. In addition, a detailed and efficient implementation of the digital front-end (DFE) for the MP TX architecture including the proposed data delay is presented. [ABSTRACT FROM AUTHOR]

Blockchain can be used to build a peer-to-peer, secure, and smart transaction system. As a horizontal technology that has changed several fields of industry, blockchain has tremendous potential to transform healthcare systems as well. In this article, a systematic review is conducted to critically evaluate 64 articles on blockchain-based healthcare systems, published between 2016 and January 2020 in 21 conferences, 33 journals, and ten online sources. The aim of this article is to answer three main questions. First, what are the applications of blockchain in the healthcare systems, and what are the structures and challenges of applying blockchain to a specific healthcare domain? Second, what are the technical, temporal, and spatial aspects of the currently developed blockchain applications for different healthcare domain? Third, what are the future research directions in designing and implementing blockchain-based healthcare systems? Statistical facts about the technical aspects of these 64 articles show that most of the proposed blockchain-based healthcare systems use private blockchain and Ethereum platforms; furthermore, the majority of the authors are affiliated with research institutions in the USA and China. We also discuss potential future research directions, e.g., integrating the blockchain in artificial intelligence based solutions, cloud-computing-based solutions, and parallel blockchain architecture. [ABSTRACT FROM AUTHOR]

While the number of women with Coronary Heart Disease requiring cardiac rehabilitation (CR) continues to increase, lack of access and other barriers to center-based CR present significant challenges. A mobile phone and wearable device-based technological system can offer home-based secondary prevention program for CHD. We have designed a women-specific digital health intervention system for use in a home-based CR program. The system that we have proposed combines human-expert intelligence with machine intelligence to enhance the decision-making capability of a health coach. We have evaluated the prototype of our system with eight women with CHD for over 13 weeks. The evaluation has shown a significant positive impact of preprogrammed intervention messages on participants’ walking performance on the same and the next day. Since increased walking activities directly improve heart health, we can directly infer that our proposed system is beneficial as a tool for secondary prevention among women with CHD. [ABSTRACT FROM AUTHOR]

While the block size of 3-D NAND flash memory increases with the density and capacity, the raw bit-error rates (RBER) of open blocks could be significantly increased. This article conducts a systematic study over reliability issues caused by open blocks, and reports several new observations. We found that the reliability degradation, due to long open time in writing a block, could happen over all layers in a 3-D NAND block, even after the block is closed. To address the reliability issues of open blocks, this article first proposes to adaptively allocate active blocks to serve write requests based on the workload characteristics for open time reduction. We then propose a partial-block refreshing strategy to alleviate the amplified RBER variations in open blocks and, thus, avoid unnecessary refreshing operations in low-RBER layers. Experimental results show that the proposed method can reduce the RBER by 43% through the reduction of the open time by 28% on average, and reduce the extra write operations for refreshing by 23% on average. [ABSTRACT FROM AUTHOR]

We demonstrate the first recurrent neural network architecture for learning signal temporal logic (TL) formulas, and present the first systematic comparison of formula inference methods. Legacy systems embed much expert knowledge which is not explicitly formalized. There is great interest in learning formal specifications that characterize the ideal behavior of such systems—that is, formulas in TL that are satisfied by the system’s output signals. Such specifications can be used to better understand the system’s behavior and improve the design of its next iteration. Previous inference methods either assumed certain formula templates, or did a heuristic enumeration of all possible templates. This work proposes a neural network architecture that infers the formula structure via gradient descent, eliminating the need for imposing any specific templates. It combines the learning of formula structure and parameters in one optimization. Through systematic comparison, we demonstrate that this method achieves similar or better misclassification rates (MCRs) than enumerative and lattice methods. We also observe that different formulas can achieve similar MCR, empirically demonstrating the under-determinism of the problem of TL inference. [ABSTRACT FROM AUTHOR]

Deep neural networks (DNNs) are being heavily utilized in modern applications, putting energy-constraint devices to the test. To bypass high energy consumption issues, approximate computing has been employed in DNN accelerators to balance out the accuracy-energy reduction trade-off. However, the approximation-induced accuracy loss can be very high and drastically degrade the performance of the DNN. Therefore, there is a need for a fine-grain mechanism that would assign specific DNN operations to approximation to maintain acceptable DNN accuracy, while achieving low energy consumption. We present an automated framework for weight-to-approximation mapping through formal property exploration for approximate DNN accelerators. At the MAC unit level, our experimental evaluation surpassed already energy-efficient mappings by more than $\times 2$ in terms of energy gains, while supporting a fine-grain control over the introduced approximation. [ABSTRACT FROM AUTHOR]

This communication presents a novel systematic design of a high-aperture-efficiency and 2-D beam-scanning nematic liquid-crystal (LC)-based reflectarray (LCRA) that operates in the sixth-generation (6G) midband (7–24 GHz). Despite a 260° phase range, the maximum aperture efficiency is 35.8% at an aperture dimension (F/D) ratio of 0.58, the highest aperture efficiency at the lowest F/D ratio among LCRAs designed to operate on the mmWave band. The proposed LC-based reflectarray unit cell (LC-RUC) has significantly low reflection loss compared to other LC-RUCs. Also, the bias topology of the proposed LC-RUC makes the LCRA capable of 2-D beam scanning. The beam-scanning range of the proposed LCRA is ±50° on the xoz plane and 0°–65° in the yoz plane at 9.55 GHz. A $2 \times 2 $ patch array antenna is designed as the feed antenna to achieve a small F/D ratio system and ease of optimization. When designing the feed antenna, the number of elements or the element spacing is considered to achieve high feed efficiency. In addition, the fabricated planar feed antenna can be easily integrated with a 3-D printed jig in which the focal length can be adjusted for optimization. The lowest side lobe level (SLL) of the proposed LCRA is −15.5 dB. [ABSTRACT FROM AUTHOR]

The accuracy of the first-order multiplicative (Ott–Clemmow) and additive (van der Waerden) modified saddle point integration methods for the Sommerfeld problem of a vertical Hertzian dipole over a lossy half-space is investigated using two theoretically equivalent formulations with either a positive or a negative image term extracted. It is demonstrated that whereas the additive method leads to the same asymptotic field representation irrespective of the sign of the image, the multiplicative variant yields distinct results in these two cases, both of which differ from the unique result of the additive method. It is further found that the positive-image Ott–Clemmow method yields the well-known Norton formula, but the negative-image variant is inaccurate and predicts a zero field in the on-surface transmitter–receiver configuration. It is also demonstrated that the first-order multiplicative method yields an incomplete representation of the first order in the inverse distance. [ABSTRACT FROM AUTHOR]

Analysis and measurement validation of Marchand and Transformer baluns is presented in this brief that compares key performance metrics including amplitude and phase balance, circuit size, bandwidth and impedance match. Whilst novel variants of these circuits have been published in the open literature to improve their performance by direct compensation, there yet remains a fundamental comparison of the core coupled-line structures to reveal a systematic design procedure for baluns. Simple analytical equations are derived for both the baluns to reveal a deep analytical insight and a basis for performance comparison. It is then validated by measurement on the same gallium arsenide wafer, which is demonstrated for the first time. A systematic design approach is summarized that can be followed by other designers that has resulted in state-of-the-art performance for both balun types without the need for additional compensation and or tuning techniques at the output ports. The Marchand balun covers a frequency range of 30-65 GHz with a measured amplitude and phase imbalance less than 0.7 dB and 1.2° respectively. The transformer balun covers a frequency range of 30-45 GHz with a measured amplitude and phase imbalance less than 0.2 dB and 0.9° respectively. [ABSTRACT FROM AUTHOR]

Contribution: In this study, we accumulated the knowledge and generated evidence on how and in what context CDIO framework has been used in software engineering (SE) education. The aggregated evidence will enable SE academics in making informed decisions while adopting CDIO for SE education and build upon it. Background: CDIO framework is relevant for SE as it focuses on enabling engineering graduates in conceiving, designing, implementing, and operating complex systems and products. We were not able to find any study that identifies and aggregates the evidence on the use of CDIO for SE education. Research Questions: This study attempts to answer the following research questions: 1) how CDIO has been used in SE education? and 2) what are the experiences of academics in applying the CDIO framework in SE education? Methodology: Using a mixed-method approach (systematic mapping study and interview study with experienced academics in SE), we established the state of the art and practice on the use of CDIO in SE education. Findings: Getting a commitment from the higher management, teachers, and students is a major challenge in the adoption of the CDIO initiative followed by a lack of competence, finance, and resources. Ownership, motivation, persistence, and training of teachers and students are required not only to adopt CDIO for SE but also to sustain it. [ABSTRACT FROM AUTHOR]

We present two lower bounds on sub-packetization level $\alpha $ of MSR codes with parameters $(n, k, d=n-1, \alpha)$ where $n$ is the block length, $d$ is the number of helper nodes contacted during single-node repair, $\alpha $ the sub-packetization level and $k\alpha $ the scalar dimension. The first bound we present is for any MSR code and is given by $\alpha \ge e^{\frac {(k-1)(r-1)}{2r^{2}}}$. The second bound we present is for the case of optimal-access MSR codes and the bound is given by $\alpha \ge \min \left\{{ r^{\frac {n-1}{r}}, r^{k-1} }\right\}$. There exist optimal-access MSR constructions that achieve the second sub-packetization level bound with an equality making this bound tight. We also prove that for an optimal-access MSR code to have optimal sub-packetization level under the constraint that the $\beta $ scalar symbol indices we access from a given helper node is dependent only on the index of the failed node, it is necessary that the support of the parity-check matrix be the same as the support structure of the existing MSR constructions in literature such as the Clay code. [ABSTRACT FROM AUTHOR]

We consider construction of deletion and substitution correcting codes with low redundancy and efficient encoding/ decoding. First, by simplifying the method of Sima et al. (ISIT 2020), we construct a family of binary single-deletion $s$ -substitution correcting codes with redundancy $(s+1) (2s+1)\log _{2} n+o(\log _{2} n)$ and encoding complexity $O(n^{2})$ , where $n$ is the blocklength of the code and $s\geq 1$. The construction can be viewed as a generalization of Smagloy et al.’s construction (ISIT 2020), and for the special case of $s=1$ , our construction is a slight improvement in redundancy of the existing works. Further, we modify the syndrome compression technique by combining a precoding process and construct a family of systematic $t$ -deletion $s$ -substitution correcting codes with polynomial time encoding/decoding algorithms for both binary and nonbinary alphabets, where $t\geq 1$ and $s\geq 1$. Specifically, our binary $t$ -deletion $s$ -substitution correcting codes of length $n$ have redundancy $(4t+3s)\log _{2}n+o(\log _{2}n)$ , whereas, for $q$ being a prime power, the redundancy of $q$ -ary $t$ -deletion $s$ -substitution codes is asymptotically $\left({4t+4s-1-\lfloor \frac {2s-1}{q}\rfloor }\right)\vphantom {{\lfloor \frac {2s-1}{q}\rfloor }_{j}}\log _{q} n + o(\log _{q}n)$ as $n\to \infty $. We also construct a family of binary systematic $t$ -deletion correcting codes (i.e., $s=0$) with redundancy $(4t-1)\log _{2} n+o(\log _{2} n)$. The proposed constructions improve upon the redundancy of the state-of-the-art constructions. [ABSTRACT FROM AUTHOR]

Since real-world objects and their interactions are often multi-modal and multi-typed, heterogeneous networks have been widely used as a more powerful, realistic, and generic superclass of traditional homogeneous networks (graphs). Meanwhile, representation learning (a.k.a. embedding) has recently been intensively studied and shown effective for various network mining and analytical tasks. In this work, we aim to provide a unified framework to deeply summarize and evaluate existing research on heterogeneous network embedding (HNE), which includes but goes beyond a normal survey. Since there has already been a broad body of HNE algorithms, as the first contribution of this article, we provide a generic paradigm for the systematic categorization and analysis over the merits of various existing HNE algorithms. Moreover, existing HNE algorithms, though mostly claimed generic, are often evaluated on different datasets. Understandable due to the application favor of HNE, such indirect comparisons largely hinder the proper attribution of improved task performance towards effective data preprocessing and novel technical design, especially considering the various ways possible to construct a heterogeneous network from real-world application data. Therefore, as the second contribution, we create four benchmark datasets with various properties regarding scale, structure, attribute/label availability, and etc. from different sources, towards handy and fair evaluations of HNE algorithms. As the third contribution, we carefully refactor and amend the implementations and create friendly interfaces for 13 popular HNE algorithms, and provide all-around comparisons among them over multiple tasks and experimental settings. By putting all existing HNE algorithms under a unified framework, we aim to provide a universal reference and guideline for the understanding and development of HNE algorithms. Meanwhile, by open-sourcing all data and code, we envision to serve the community with an ready-to-use benchmark platform to test and compare the performance of existing and future HNE algorithms (https://github.com/yangji9181/HNE). [ABSTRACT FROM AUTHOR]

Despite the rapidly increasing interest in analog multibeam antennas, there has been a lack of systematic theoretical approaches to synthesizing circuit-type multiple beamforming networks, such as the Blass matrix and the Nolen matrix. To address the issue, this article presents a new concept, the generalized joined coupler (GJC) matrix, which encapsulates both the Blass matrix and the Nolen matrix, as well as their variants, and presents a novel theoretical framework for generating individually and independently controllable multiple beams using the GJC matrix. A GJC matrix has $N $ columns to feed $N $ antenna elements and $M $ rows to feed $M $ beams, and the direction of each individual beam can be controlled by tuning the phase shifters in the associated row of the GJC matrix. In this article, a matrix theory is developed, and an optimization algorithm is proposed to provide a mathematical tool for synthesizing such matrices and, consequently, the multiple beams. Using a particle swarm optimization algorithm, numerical results demonstrate that multibeams with independent control of individual beam directions and sidelobes can, indeed, be synthesized in a systematic manner. Specifically, two GJC matrix variants, the Blass-like matrix and the Nolen-like matrix, are investigated. [ABSTRACT FROM AUTHOR]

Spatial defect patterns on semiconductor wafer bin maps can provide valuable information on the root causes of process abnormalities. Thus, the identification of these patterns is important for quality management and yield improvement. To date, most research has focused on the case of a single defect pattern. The recognition of mixed-type patterns is challenging as the patterns need to be separated into clusters and each cluster classified as a predefined type of defect pattern. In this study, we propose a novel method for mixed-type defect pattern detection and recognition in wafer bin maps. We separate mixed-type defect patterns into clusters using tensor voting. Marching algorithms are then developed to extract region and curve patterns based on the structural saliency information of the voting process. Our method is inherently robust against noise and sufficiently flexible to deal with complex defect patterns. The results obtained using real and simulated data demonstrate the effectiveness of the proposed method in the detection and recognition of both single and mixed-type defect patterns. [ABSTRACT FROM AUTHOR]

This brief presents a low-power multiuser detector that can terminate its processing earlier than usual for interleave division multiple access (IDMA) systems. As a baseline detection algorithm, a recently proposed bitwise early termination (BET) is adopted. Despite algorithmically feasible, the BET has never been realized in circuitry yet, pending the demonstration of physical practicality. For the first time ever, we efficiently implement the BET in a 65-nm CMOS technology, and demonstrate that it is indeed effective in realizing a fast and low-power detector. In doing so, we organize an essential set of information bits to examine the feasibility of the BET, and define a systematic procedure of manipulating the set of bits. In addition, we build an efficient hardware architecture that enables the proposed manipulation procedure. Through an extensive comparison with the state-of-the-art detectors in the literature, we validate that the prototype implementation completes the detection at the earliest, and draws the lowest power. Specifically, the proposed 16-user detector takes 3.98 iterations per bit, and dissipates 97 mW to process one 8192-chip frame. In contrast, even the latest low-power counterpart iterates 6 times, and consumes 24% more power. [ABSTRACT FROM AUTHOR]

Contribution: In the research presented in this article, a procedure for determining student workload has been designed, tested, and validated. This procedure also makes it possible to analyze how different teaching variables are affected by workload and to visualize the learning environment generated in the course. Background: When the project-based learning (PBL) methodology is used in a course, if the students’ workload is not properly planned and controlled, important variables in the educational environment, such as the teaching organization and the students’ approach to learning, can be affected. The PBL methodology may even become unfeasible as it affects the other courses with which it shares year and semester. This justifies the need to know the student workload of a subject. The previous research has presented procedures for establishing student workload. However, they use questionnaires with a high number of questions. A questionnaire with many questions affects the reliability of students’ answers. The questionnaire presented in this article reduces the number of questions without affecting the results obtained and it is easily applicable to other courses. Research Questions: The questions to be answered in this research are: 1) is the workload of the students, when using the PBL methodology in a course, in line with the one established in the syllabus? and 2) is the learning environment created in the course as expected? Methodology: The methodology used to obtain the necessary data is based on students completing weekly surveys, two critical incident questionnaires (CIQs), and a final survey. The aim was always to minimize the number of questions to be answered, ensuring that the data collected provided a true picture of the workload and the educational environment. Findings: The analysis of the data obtained by applying the procedure provides mechanisms to control the workload, ensure involvement and motivation, improve students’ academic results and show the learning environment created in the course. The implementation of this method, during three academic years, has allowed to test its effectiveness, validate some of the initial hypotheses, and confirm the conclusions of some previous studies. [ABSTRACT FROM AUTHOR]

Contribution: Demonstrates how to use experiential learning (EL) to improve argumentative writing. Presents the design and development of a natural language processing (NLP) application for aiding instructors in providing feedback on student essays. Discusses how EL combined with automated support provides an analytical approach to improving written-communication skills. Background: High-quality, timely, feedback is an effective way to improve students’ writing. However, large class sizes and limited instructor backgrounds often make formative feedback impossible. Recent trends, including lowering entry requirements, have added to these challenges. Assistive technologies for implementing inclusive education provide viable solutions. Research Questions: 1) How and why can EL be used to develop argumentative writing skills in university STEM students? 2) How can technologies be developed to support using EL in teaching writing? and 3) How might the holistic impact of using such analytic techniques be evaluated? Methodology: Participants in an EL project were assigned two essays in sequence. They were given instructions on making good arguments and shown how to use an analytic rubric to maximize their scores. The essays were hand scored by tutors who provided scores for each dimension of the rubric. Subsequently, the content and argumentation of the essays were analyzed using NLP techniques to obtain independent scores. Qualitative data were also collected. Findings: The project produced transformative writing experiences for the participants. It showed how analytical techniques help improve writing skills and how relevant automated instructor assistance can be developed using NLP technologies. [ABSTRACT FROM AUTHOR]

This article presents approaches for efficient modeling and systematic design of enhanced phase-locked loop (ePLL) structures. While different ePLL structures have found a wide acceptance for various applications, their modeling and design aspects have not been fully and systematically reported in the existing literature. This article fills this gap by presenting an effective modeling approach for both the single- and three-phase ePLLs. The models are derived with a view to minimize the number of parameters to be adjusted to simplify the design. The models are then used to develop systematic design algorithms for their parameters. As an example, application of the ePLL in a grid-connected inverter is formulated and studied through simulation and experimental results. The design and simulation files are made available. [ABSTRACT FROM AUTHOR]

We study the rack-aware storage system where all storage nodes are organized in racks and within each rack the nodes can communicate freely without taxing the system bandwidth. Rack-aware regenerating codes (RRCs) were proposed for minimizing the repair bandwidth for single erasures. In the initial setting of RRCs, the repair of a single node requires the participation of all the remaining nodes in the rack containing the failed node as well as a large number of helper racks containing no failures. Consequently, the repair may be infeasible in front of multiple node failures. In this work, a relaxed repair model that can tolerate multiple node failures by simultaneously reducing the intra-rack connections and cross-rack connections is proposed. A tradeoff between the storage and repair bandwidth under the relaxed repair model is derived, and parameters of the two extreme points on the tradeoff curve are characterized for the minimum storage and minimum bandwidth respectively. Moreover, two codes corresponding to the extreme points are explicitly constructed over the fields of size comparable to the code length and with the lowest sub-packetization. Finally, for the convenience of practical use, systematic encoding processes for the two codes are also established. [ABSTRACT FROM AUTHOR]

Little is known about the effect of pulsed electromagnetic fields (PEMFs) as an option for preventing osteoporosis. This study sought to investigate the effectiveness of PEMFs for the management of primary osteoporosis in older adults. We searched databases from the inception to date to target trials examining the effects of PEMFs compared to placebo or sham or other agents for the management of primary osteoporosis for a meta-analysis using random effects model. Eight trials including 411 participants were included. PEMFs was non-inferior to conventional pharmacological agents and exercise respectively in preventing the decline of Bone Mineral Density (BMD) at the lumbar (MD 8.76; CI −9.64 to 27.16 and MD 1.33; CI −2.73 to 5.39) and femur neck (MD 0.04; CI −1.09 to 1.16 and MD 1.50; CI −0.26 to 3.26), and significantly improving balance function measured by Berg Balance Scale (BBS) (MD 0.91; CI 0.32 to 1.49) and Timed Up and Go test (MD −3.61; CI −6.37 to −0.85), directly after intervention. The similar trends were observed in BMD and BBS at 12- and 24-weeks follow-up from baseline. PEMFs had positive effects non-inferior to first-line treatment on BMD and better over placebo on balance function in older adults with primary osteoporosis, but with moderate to very low certainty evidence and short-term follow-ups. There is a need for high-quality randomised controlled trials evaluating PEMFs for the management of primary osteoporosis. [ABSTRACT FROM AUTHOR]