Fundamental Computer Science Concepts Research Articles

Sparcl: A language for partially invertible computation

Abstract Invertibility is a fundamental concept in computer science, with various manifestations in software development (serializer/deserializer, parser/printer, redo/undo, compressor/decompressor, and so on). Full invertibility necessarily requires bijectivity, but the direct approach of composing bijective functions to develop invertible programs is too restrictive to be useful. In this paper, we take a different approach by focusing on partially invertible functions—functions that become invertible if some of their arguments are fixed. The simplest example of such is addition, which becomes invertible when fixing one of the operands. More involved examples include entropy-based compression methods (e.g., Huffman coding), which carry the occurrence frequency of input symbols (in certain formats such as Huffman tree), and fixing this frequency information makes the compression methods invertible. We develop a language Sparcl for programming such functions in a natural way, where partial invertibility is the norm and bijectivity is a special case, hence gaining significant expressiveness without compromising correctness. The challenge in designing such a language is to allow ordinary programming (the “partially” part) to interact with the invertible part freely, and yet guarantee invertibility by construction. The language Sparcl is linear-typed and has a type constructor to distinguish data that are subject to invertible computation and those that are not. We present the syntax, type system, and semantics of the language and prove that Sparcl correctly guarantees invertibility for its programs. We demonstrate the expressiveness of Sparcl with examples including tree rebuilding from preorder and inorder traversals, Huffman coding, arithmetic coding, and LZ77 compression.

Synchronization Possibilities and Features in Java

Abstract In this paper we have discussed one of the greatest features of the general-purpose computer programming language –Java. This paper represents concepts of Synchronization possibilities and features in Java. Today’s operating systems support concept of “Multitasking”. Multitasking achieved by executing more than one task at a same time. Tasks runs on threads. Multitasking runs more than one task at a same time. Multitasking which means doing many things at the same time is one of the most fundamental concepts in computer engineering and computer science because the processor execute given tasks in parallel so it makes me think that are executing simultaneously. Multitasking is related to other fundamental concepts like processes and threads. A process is a computer program that is executing in a processor, while a thread is a part of a process that has a way of execution: it is a thread of execution. Every process has at least one thread of execution. There are two types of multitasking: process – based and thread – based. Process-based multitasking, means that on a given computer there can be more than one program or process that is executing, while thread-based multitasking, which is also known as multithreading, means that within a process, there can be more than one thread of execution, each of them doing a job and so accomplishing the job of their process. When there are many processes or many threads within processes, they may have to cooperate with each other or concurrently try to get access to some shared computer resources like: processor, memory and input/output devices. They may have to, for example: print a file in a printer or write and/or read to the same file. We need a way of setting an order, where processes and/or threads could do their jobs (user jobs) without any problem, we need to synchronize them. Java has built-in support for process and thread synchronization, there are some constructs that we can use when we need to do synchronization.This paper, a first phase discussed the concept of Parall Programming, threads, how to create a thread, using a thread, working with more than one thread. Second phase is about synchronization, what is in general and in the end we disscused the synchronization possibilities and feautures in Java.

A Gender-Related Analysis of a Robots' Math Class

Using robot programming activities for learning in the classroom is one way to drive interest and engagement in the STEM field among students, especially girls. And this is a field that is particularly characterized by an underrepresentation of women. Accordingly, many countries are increasingly integrating activities related to computer science concepts into their education systems. The EU also sets the goal of considering the connections between STEM disciplines in schools and having students gain experience with robots as well. The use of robots for teaching purposes creates opportunities for motivating and meaningful mathematics lessons that are linked to the fundamental concepts of computer science. Mathematics teaching in such a context offers possibilities for an experimental and problem-oriented approach to the content and a deep insight into mathematical concepts. Research in this area shows that the use of robots can promote understanding of mathematical concepts, change attitudes and motivation, and develop metacognitive and problem-solving skills. However, as for gender differences in this context, little is known to date. Addressing this gap, for this work, we investigated learners' performance, mathematical and computational ideas and experiences, problem-solving strategies, and help used in an ER (Educational Robotics) activity. In addition, the learners’ mathematical competence and computational thinking skills as well as possible correlations of these measures with the learners’ performance on an ER activity were examined. For these purposes, an ER activity on the topic of plane geometric figures was designed, which was carried out in a 6th grade (11-12 years) class (n=24) of an Austrian middle school in the city of Salzburg using the TI-Innovator Rover. The comparison of six female and six male student groups, each consisting of two students, made it possible to address the above research questions. For this purpose, a mixed-methods approach was chosen. Qualitative data, consisting of the audio recordings of the student groups' conversations during the ER activity, the constructions made on the posters, the student notes, and the saved programs, form the basis for thematic analysis. The quantitative data include the number of tasks solved during the ER activity by the student groups, the mathematics grade of the last school year by the students, and the results of a test on the students' computational thinking skills with the related self-assessments. Appropriate quantitative methods for analysis include the Wilcoxon rank-sum test (Mann-Whitney test), the Welch Two Sample t-test, and Kendall's tau and Pearson's correlation coefficient to test for differences and correlations. The main results indicate that groups with female students perform better while showing high engagement in the activity, exhibit a more systematic approach to problem-solving and at the same time use less intensive help from the teachers than their male counterparts in this class. The paper concludes by giving future directions for research and the limits of the present work.

A Novel Three-Way Decision Model for Improving Computational Thinking Based on Grey Correlation Analysis

Computational thinking (CT) is an approach that applies the fundamental concepts of computer science to solve problems, design systems, and understand human behavior, which can help students develop lifetime learning and generate new topics. It has been the elements of competency expected of the next generation of talents. However, the current research on computational thinking evaluation is still at a relatively weak stage. The existing related evaluation research is still limited to traditional curriculum evaluation methods. Therefore, the training effect of computational thinking cannot be well quantified, and the characteristics of students cannot be further explored. In this work, we propose a three-way decision model for improving computation thinking. We first developed a system of evaluation metrics, including five specific primary indicators and several secondary indicators. Next, the weight of each indicator was determined by applying an expert similarity measure, consequently getting the best metric sequence. We employ a grey correlation analysis to calculate the distance of each test result from this optimal sequence. Then, we trisect the set of testers based on the distance to build three regions of high score sequences, medium score sequences, and low score sequences inspired by the three-way decision. We can then exploit these rules on target students in the relatively low regions to improve their computational thinking. An example analysis illustrates the effectiveness and applicability of the method. This article provides a solid theoretical basis for improving students’ computational thinking ability. Teaching administrators can conveniently formulate computational thinking teaching strategies, and timely warning and intervention for students with poor computational thinking ability can effectively improve students’ computational thinking ability. The corresponding training measures are given to students of different ability levels to achieve differentiated and personalized training.

Computational Abstraction.

Representation and abstraction are two of the fundamental concepts of computer science. Together they enable “high-level” programming: without abstraction programming would be tied to machine code; without a machine representation, it would be a pure mathematical exercise. Representation begins with an abstract structure and seeks to find a more concrete one. ion does the reverse: it starts with concrete structures and abstracts away. While formal accounts of representation are easy to find, abstraction is a different matter. In this paper, we provide an analysis of data abstraction based upon some contemporary work in the philosophy of mathematics. The paper contains a mathematical account of how Frege’s approach to abstraction may be interpreted, modified, extended and imported into type theory. We argue that representation and abstraction, while mathematical siblings, are philosophically quite different. A case of special interest concerns the abstract/physical interface which houses both the physical representation of abstract structures and the abstraction of physical systems.

Sparcl: a language for partially-invertible computation

Invertibility is a fundamental concept in computer science, with various manifestations in software development (serializer/deserializer, parser/printer, redo/undo, compressor/decompressor, and so on). Full invertibility necessarily requires bijectivity, but the direct approach of composing bijective functions to develop invertible programs is too restrictive to be useful. In this paper, we take a different approach by focusing on partially-invertible functions—functions that become invertible if some of their arguments are fixed. The simplest example of such is addition, which becomes invertible when fixing one of the operands. More involved examples include entropy-based compression methods (e.g., Huffman coding), which carry the occurrence frequency of input symbols (in certain formats such as Huffman tree), and fixing this frequency information makes the compression methods invertible. We develop a language Sparcl for programming such functions in a natural way, where partial-invertibility is the norm and bijectivity is a special case, hence gaining significant expressiveness without compromising correctness. The challenge in designing such a language is to allow ordinary programming (the “partially” part) to interact with the invertible part freely, and yet guarantee invertibility by construction. The language Sparcl is linear-typed, and has a type constructor to distinguish data that are subject to invertible computation and those that are not. We present the syntax, type system, and semantics of the language, and prove that Sparcl correctly guarantees invertibility for its programs. We demonstrate the expressiveness of Sparcl with examples including tree rebuilding from preorder and inorder traversals and Huffman coding.

Genetic programs can be compressed and autonomously decompressed in live cells.

Fundamental computer science concepts inspired novel information-processing molecular systems in test tubes1–13 and genetically-encoded circuits in live cells14–21. Recent research showed that digital information storage in DNA, implemented using deep sequencing and conventional software, can approach the maximum Shannon information capacity22 of 2 bits per nucleotide23. DNA is used in nature to store genetic programs, but the information content of natural encoding rarely approaches this maximum24. We hypothesize that the biological function of a genetic program can be preserved while reducing the length and increasing the information content of its DNA encoding. Here we support this hypothesis by describing an experimental procedure for compressing a genetic program and its subsequent autonomous decompression and execution in human cells. As a test-bed we choose an RNAi cell classifier circuit25 that comprises redundant DNA sequence and is therefore amenable for compression, as are many other complex gene circuits15, 18, 26–28. In one example, we implement a compressed encoding of a ten-gene four-input AND gate circuit using only four genetic constructs. The compression principles applied to gene circuits can enable fitting complex genetic programs into DNA delivery vehicles with limited cargo capacity, and storing compressed and biologically inert programs in vivo for on-demand activation.

Behavioural sequential analysis of using an instant response application to enhance peer interactions in a flipped classroom

ABSTRACTTo stimulate classroom interactions, this study employed two different smartphone application modes, providing an additional instant interaction channel in a flipped classroom teaching fundamental computer science concepts. One instant interaction mode provided the students (N = 36) with anonymous feedback in chronological time sequence, while the other showed their feedback by “like” ranking (N = 26). The behavioural patterns of undergraduates using these two different modes were compared. The results showed that the like-ranked feedback deepened the interaction between asking and answering questions, reduced the number of irrelevant messages, and increased attention to questionable messages. The students using the like-ranking mode also received more encouragement during the flipped classroom discussion activities.

Teaching Nondeterminism Through Programming

Nondeterminism (ND) is a fundamental concept in computer science, and comes in two main flavors. One is the kind of ND that appears in automata theory and formal languages, and is the one that students are usually introduced to. It is known to be hard to teach. We present here a study, in which we introduced students to the second kind of ND, which we term opera- tive. This kind of ND is quite different from the first one. It appears in nondeterministic program - ming languages and in the context of concurrent and distributed programming. We study how high-school students understand operative ND after learning the nondeterministic programming language of live sequence charts (LSC). To assess students' learning, we used a two-dimensional taxonomy that is based upon the SOLO and the Bloom taxonomies. Our findings show that after a semestrial course on LSC, high-school students with no previous experience with ND of either type, understood operative ND on a level that allowed them to create and execute programs that included nondeterminism on various levels and in various degrees of complexity. We believe that it is important to expose students to the two types of ND, especially as ND has become a very prominent characteristic of computerized systems. Our findings suggest that students can reach a significant understanding of operative ND when the concept is introduced in the context of a programming course.

MODELING IN MAPLE AS THE RESEARCHING MEANS OF FUNDAMENTAL CONCEPTS AND PROCEDURES IN LINEAR ALGEBRA

The article is devoted to binary technology and "fundamental training technology." Binary training refers to the simultaneous teaching of mathematics and computer science, for example differential equations and Maple, linear algebra and Maple. Moreover the system of traditional course of Maple is not performed. The use of the opportunities of Maple-technology in teaching mathematics is based on the following fundamental concepts of computer science as an algorithm,program, a linear program, cycle, branching, relative perators, etc. That’s why only a certain system of command operators in Maple is considered. They are necessary for fundamental concepts of linear algebra and differential equations studying in Maple-environment. Relative name - "the technology of fundamental training" reflects the study of fundamental mathematical concepts and procedures that express the properties of these concepts in Maple-environment. This article deals with the study of complex fundamental concepts of linear algebra (determinant of the matrix and algorithm of its calculation, the characteristic polynomial of the matrix and the eigenvalues of matrix, canonical form of characteristic matrix, eigenvectors of matrix, elementary divisors of the characteristic matrix, etc.), which are discussed in the appropriate courses briefly enough, and sometimes are not considered at all, but they are important in linear systems of differential equations, asymptotic methods for solving differential equations, systems of linear equations. Herewith complex and voluminous procedures of finding of these linear algebra concepts embedded in Maple can be performed as a result of a simple command-operator. Especially important issue is building matrix to canonical form. In fact matrix functions are effectively reduced to the functions of the diagonal matrix or matrix in Jordan canonical form. These matrices are used to rise a square matrix to a power, to extract the roots of the n-th degree of a square matrix, to calculate matrix exponent, etc. The author creates four basic forms of canonical models of matrices and shows how to design matrices of similar transformations to these four forms. We introduce the programs-procedures for square matrices construction based on the selected models of canonical matrices. Then you can create a certain amount of various square matrices based on canonical matrix models, it allows to use individual learning technologies. The use of Maple-technology allows to automate the cumbersome and complex procedures for finding the transformation matrices of canonical form of a matrix, values of matrices functions, etc., which not only saves time but also attracts attention and efforts on understanding the above mentioned fundamental concepts of linear algebra and procedures for investigation of their properties. All these create favorable conditions for the use of fundamental concepts of linear algebra in scientific and research work of students and undergraduates using Maple-technology.

Synchronization Possibilities and Features in Java

In this paper we have discussed one of the greatest features of the general purpose computer programming language –Java. This paper represents concepts of Synchronization possibilities and features in Java. Today's operating systems support concept of "Multitasking". Multitasking achieved by executing more than one task at a same time. Tasks runs on threads. Multitasking runs more than one task at a same time. Multitasking which means doing many things at the same time is one of the most fundamental concepts in computer engineering and computer science because the processor execute given tasks in parallel so it makes me think that are executing simultaneously. Multitasking is related to other fundamental concepts like processes and threads. A process is a computer program that is executing in a processor, while a thread is a part of a process that has a way of execution: it is a thread of execution. Every process has at least one thread of execution. There are two types of multitasking: process – based and thread – based. Process-based multitasking, means that on a given computer there can be more than one program or process that is executing, while thread-based multitasking, which is also known as multithreading, means that within a process, there can be more than one thread of execution, each of them doing a job and so accomplishing the job of their process. When there are many processes or many threads within processes, they may have to cooperate with each other or concurrently try to get access to some shared computer resources like: processor, memory and input/output devices. They may have to, for example: print a file in a printer or write and/or read to the same file. We need a way of setting an order, where processes and/or threads could do their jobs (user jobs) without any problem, we need to synchronize them. Java has built-in support for process and thread synchronization, there are some constructs that we can use when we need to do synchronization.This paper, a first phase discussed the concept of Parall Programming, threads, how to create a thread, using a thread, working with more than one thread. Second phase is about synchronization, what is in general and in the end we disscused the synchronization possibilities and feautures in Java.

Generative Tools for Interactive Composition: Real-Time Musical Structures Based on Schaeffer's TARTYP and on Klumpenhouwer Networks

Interactive computer music is comparable to improvisation because it includes elements of real-time composition performed by the computer. This process of real-time composition often incorporates stochastic techniques that remap a predetermined fundamental structure to a surface of sound processing. The hierarchical structure is used to pose restrictions on the stochastic processes, but, in most cases, the hierarchical structure in itself is not created in real time. This article describes how existing musical analysis methods can be converted into generative compositional tools that allow composers to generate musical structures in real time. It proposes a compositional method based on generative grammars derived from Pierre Schaeffer's TARTYP, and describes the development of a compositional tool for real-time generation of Klumpenhouwer networks. The approach is based on the intersection of musical ideas with fundamental concepts in computer science including generative grammars, predicate logic, concepts of structural representation, and various methods of categorization.

The concept of nondeterminism

Nondeterminism is a fundamental concept in computer science that appears in various contexts such as automata theory, algorithms and concurrent computation. We present a taxonomy of the different ways that nondeterminism can be defined and used; the categories of the taxonomy are domain, nature, implementation, consistency, execution and semantics. An historical survey shows how the concept was developed from its inception by Rabin & Scott, Floyd and Dijkstra, as well the interplay between nondeterminism and concurrency. Computer science textbooks and pedagogical software are surveyed to determine how they present the concept; the results show that the treatment of nondeterminism is generally fragmentary and unsystematic. We conclude that the teaching of nondeterminism must be integrated through the computer science curriculum so that students learn to see nondeterminism both in terms of abstract mathematical entities and in terms of machines whose execution is unpredictable.

QuickDraw

This paper describes a new tool for introducing computer graphics and multimedia applications into first year, called QuickDraw , and our experience using it. QuickDraw provides an easy to use language and platform independent interface which permits students to create multimedia applications beginning with their first assignment in an introductory computer science course. QuickDraw has been carefully designed to avoid complex "magical" statements in order to setup, use, or tear down the multimedia environment, making it an appropriate tool for use with students with no prior programming experience. As instructors, we have found that QuickDraw effectively engages students by allowing them to create visually impressive programs with minimal complexity, while continuing to allow us to effectively teach fundamental computer science concepts.

The Concept of Nondeterminism: Its Development and Implications for Teaching

Nondeterminism is a fundamental concept in computer science that appears in various contexts such as automata theory, algorithms and concurrent computation. We present a taxonomy of the different ways that nondeterminism can be defined and used; the categories of the taxonomy are domain, nature, implementation, consistency, execution and semantics. An historical survey shows how the concept was developed from its inception by Rabin & Scott, Floyd and Dijkstra, as well as the interplay between nondeterminism and concurrency. Computer science textbooks and pedagogical software are surveyed to determine how they present the concept; the results show that the treatment of nondeterminism is generally fragmentary and unsystematic. We conclude that the teaching of nondeterminism must be integrated through the computer science curriculum so that students learn to see nondeterminism both in terms of abstract mathematical entities and in terms of machines whose execution is unpredictable.

Introducing propositional logic and queueing theory with the infotraffic interactive learning environments

InfoTraffic [2] is a collection of learning environments forteaching fundamental concepts of computer science and mathematics. So far, the two programs LogicTraffic, targeted at propositional logic, and QueueTraffic, targeted at queueing theory have been released 1 . Both are freely availableand can be downloaded (along with teaching materials) from [1]. This demonstration abstract gives a very brief introductionto these two programs and their use in class.

Catch that speeding turtle

Graphics are a great way to keep students motivated early in a computer science program. This paper introduces a simple Ada graphics package that simultaneously meets two goals: it provides a easy to understand graphics package that leads to enjoyable projects in CS1, and it is an appropriate tool for teaching fundamental computer science concepts to beginning programmers. The package is an Ada implementation and extension of a Java TutleGraphics package used at a number of universities.

Compression of Words Over a Partially Commutative Alphabet

Concurrency is a fundamental concept in computer science which is concerned with the study of systems involving multiple processes. The order of events in a concurrent system is unpredictable because of the independence of events occurring in the individual processes. Trace theory is a successful model for the execution of concurrent processes which employs congruence classes of words over partially commutative alphabets. These congruence or interchange classes generalize the more familiar notions of strings and type classes. Motivated by recent work in the areas of program profiling and compression of executable code, we consider a rate distortion problem in which the objective is to reproduce a string which is equivalent to the original string. This leads to a generalization of Kolmogorov complexity and a new graph entropy called the interchange entropy. We provide some of the basic properties of the interchange entropy. We also consider some universal compression schemes for this problem and show that for a large collection of dependence alphabets we can asymptotically attain the interchange entropy.

Demonstration of a universal surface DNA computer.

A fundamental concept in computer science is that of the universal Turing machine, which is an abstract definition of a general purpose computer. A general purpose (universal) computer is defined as one which can compute anything that is computable. It has been shown that any computer which is able to simulate Boolean logic circuits of any complexity is such a general purpose computer. The field of DNA computing was founded in 1994 by Adleman's solution of a 7-bit instance of the Hamiltonian path problem. This work, as well as most of the subsequent experimental and theoretical investigations in the area, focused primarily upon the solution of NP-complete problems, which are a subset of the larger universal class of problems. In the present work a surface DNA computer capable of simulating Boolean logic circuits is demonstrated. This was done by constructing NOR and OR gates and combining them into a simple logic circuit. The NOR gate is one of the universal gates in Boolean logic, meaning that any other logic gate can be built from it alone. The circuit was solved using DNA-based operations, demonstrating the universal nature of this surface DNA computing model.

Mental models of recursion

Recursion is a fundamental concept in Computer Science. A student's knowledge of recursion can be termed their mental model of recursion. A student's mental model is viable if it allows them to accurately and consistently represent the mechanics of recursion. Non-viable mental models are constructed if students have misconceptions about the mechanisms of recursion or have misconceptions about concepts fundamental to recursion. This paper presents a study of the mental models of recursion that first year students at the University of the Witwatersrand have constructed in 2000, 2001 and 2002. It was found that while the majority of students constructed the viable copies model, many non-viable models such as the looping , active , step , magic , return-value and various odd models were also constructed. Identifying the models that students have can allow lecturers to target individual students' specific problems and analysis of the models can provide insight into learning.