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An augmented reality app for real-time analysis of direct current in resistive circuits is presented. The app allows the manipulation of circuit elements and computes the values of voltage and current intensity using the loop method and applying the Kirchhoff’s voltage law. The app can be used in theoretical classes and laboratories. The contributions of this paper are two-fold. First, the app has higher levels of interactivity than other apps in the same domain since it allows defining the configuration and the parameters of the circuit. Second, the app performs more complex computations than similar apps in real-time.

A new algorithmic model (cTAM) of self-assembly of electronic resistive circuits akin to models for DNA self-assembly has been recently introduced and a complete characterization of their shape and properties has been given for one-dimensional electric ladders. Growth is controlled by thresholding of the energy required for attachments of new components to a growing assembly. In this sequel, we characterize an analogous family of two-dimensional resistive circuit grids self-assemblable in the cTAM model. These circuits have remained unresolved for some time in full generality. Fundamental questions concerning the size, shape, and energy distribution of the assembly sequences and their steady-state in large scales are addressed in full.

In this study, we aim to establish the factors that explain the technology acceptance of augmented reality (AR) in students’ engineering education. Technology acceptance of AR apps has been insufficiently investigated. We conceive a theoretical model to explain technology acceptance by relating behavioral intention to use with the variables subjective norm, technology optimism, technology innovativeness, perceived ease of use, perceived usefulness, and attitude toward using. An interactive AR app on electrical circuits was designed to assist students to overcome their difficulties in understanding how electricity works. A theoretical model was hypothesized and tested using structural equation modeling. The study was conducted using a sample of 190 engineering students. The results demonstrate the positive effect of technology optimism and technology innovativeness on perceived usefulness and attitude toward using, respectively. Furthermore, they suggest that attitude toward using is influenced by perceived usefulness but not directly by perceived ease of use. This could mean that students would be willing to use this app if they find it useful and not just easy to use. Finally, the results illustrate that attitude toward using firmly explains behavioral intention to use, which is consistent with the findings in previous studies. These results could guide how academics and higher education centers should approach the incorporation of these technologies in classrooms.

Neste trabalho apresentamos uma sequência didática experimental utilizando material de baixo custo e fácil acesso, na qual circuitos elétricos resistivos simétricos são conceituados e montados. Também é ilustrado de forma concreta o Teorema do Ponto Médio (TPM). Tal trabalho objetiva acrescentar, ao pequeno número de trabalhos experimentais envolvendo circuitos elétricos resistivos simétricos, uma proposta que aborde o assunto de forma lúdica e leve. Fazemos isso por meio do uso de lâmpadas incandescentes-halógenas como resistores, pois, nesse caso, temos um excelente indicativo visual de como a corrente elétrica está se distribuindo e, consequentemente, tem-se uma visualização direta da simetria ou não existente. In this work we present an experimental didactic sequence using low cost and easy access material, in which two-dimensional (2D) and symmetrical resistive electrical circuits are conceptualized and assembled. The Middle Point Theorem (MPT) is concretely illustrated. Such work aims to try to fill a gap: the absence of experiments involving symmetrical resistive electrical circuits. We do this by using incandescent-halogen lamps as resistors, because, in this case, we have an excellent visual indicator of how the electric current is being distributed and, consequently, there is a direct visualization of the symmetry or its non-existence.

Let $N$ be a circuit composed of a finite number of positive and negative linear resistors, ideal diodes, nullators, norators and independent current and voltage sources. In this article, we consider the problem to determine, without any numerical computation, the state of a diode of $N$ . We propose a set of topological conditions such that, when verified by a diode of $N$ , the state of the diode is determined and the same in all the solutions of $N$ . Our results may simplify, sometimes dramatically, the usual trial-and-error procedure to find the solutions of $N$ .

[This paper is part of the Focused Collection on Curriculum Development: Theory into Design.] We argue that teaching learning sequence (TLS) design needs to be further developed through the explicit articulation of methodology, which comprises the theoretical commitments regarding research and how those give rise to methods for design, implementation and assessment. In this study we propose design based research (DBR) as a methodology to conduct systematic and iterative studies of the design and assessment of educational interventions (such as materials and strategies) as solutions to complex problems in educational practice. This methodology does not specify theoretical commitments regarding the nature of learning and how those give rise to teaching strategies, but the articulation of those commitments is expected as part of the justification for decision making in the design process. In order to demonstrate the framework, we present an example of TLS development in the context of introductory electrostatics and dc circuits. We describe the evaluation of the TLS over three years of implementation, addressing both the capacity of the TLS for involving students in learning the topic and the students’ learning itself.

In this chapter, some of the concepts introduced in Chap. 9 are extended to nonlinear first-order circuits, also making reference to potential functions for resistive circuits. In particular, some circuits with piecewise-linear nonlinearities (either original or obtained by approximation) are studied, showing the advantages of this kind of formulation, which makes it possible to find the solution analytically, whereas in the general case we usually have to resort to numerical solutions.

This paper presents a simple and efficient method for finding all characteristic curves of piecewise-linear resistive circuits using integer programming. In this method, the problem of finding all characteristic curves is formulated as a mixed integer programming problem, and it is solved by an integer programming solver CPLEX. It is shown that the proposed method can be implemented easily without writing complicated programs. It is also shown that all characteristic curves are obtained by solving a mixed integer programming problem only once. Numerical examples are given to confirm the effectiveness of the proposed method.

In this paper, we report on using mass transport to control nutrition supply of colorectal cancer cells for developing a microtumor in a confined microchamber. To mimic the spatial heterogeneity of a tumor, two microfluidic configurations based on resistive circuits are designed. One has a convection-dominated microchamber to simulate the tumor region proximal to leaky blood vessels. The other has a diffusion-dominated microchamber to mimic the tumor core that lacks blood vessels and nutrient supply. Thus, the time for nutrition to fill the microchamber can vary from tens of minutes to several hours. Results show that cells cultured under a diffusive supply of nutrition have a high glycolytic rate and a nearly constant oxygen consumption rate. In contrast, cells cultured under convective supply of nutrition have a gradual increase of oxygen consumption rate with a low glycolytic rate. This suggests that cancer cells have distinct reactions under different mass transport and nutrition supply. Using these two microfluidic platforms to create different rate of nutrition supply, it is found that a continuous microtumor that almost fills the mm-size microchamber can be developed under a low-nutrient supply environment, but not for the convective condition. It also is demonstrated that microchannels can simulate the delivery of anti-cancer drugs to the microtumor under controlled mass-transport. This method provides a means to develop a larger scale microtumor in a lab-on-a-Chip system for post development and stimulations, and microchannels can be applied to control the physical and chemical environment for anti-cancer drug screening.

This paper presents a novel design for a test platform to determine the state of health (SOH) of lithium-ion batteries (LIBs). The SOH is a key parameter of a battery energy storage system and its estimation remains a challenging issue. The batteries that have been tested are 18,650 Li-ion cells as they are the most commonly used batteries on the market. The test platform design is detailed from the building of the charging and discharging circuitry to the software. Data acquired from the testing circuitry are stored and displayed in LabVIEW to obtain the charging and discharging curves. The resulting graphs are compared to the outcome predicted by the battery datasheets, to verify that the platform delivers coherent values. The SOH of the battery is then calculated using a Coulomb counting method in LabVIEW. The batteries will be discharged through various types of resistive circuits, and the differences in the resulting curves will be discussed. A single battery cell will also be tested over 30 cycles and the decrease in the SOH will be clearly identified.

Recommender systems have been widely used for predicting unknown ratings. Collaborative filtering as a recommendation technique uses known ratings for predicting user preferences in the item selection. However, current collaborative filtering methods cannot distinguish malicious users from unknown users. Also, they have serious drawbacks in generating ratings for cold-start users. Trust networks among recommender systems have been proved beneficial to improve the quality and number of predictions. This paper proposes an improved trust-aware recommender system that uses resistive circuits for trust inference. This method uses trust information to produce personalized recommendations. The result of evaluating the proposed method on Epinions dataset shows that this method can significantly improve the accuracy of recommender systems while not reducing the coverage of recommender systems.

Este trabalho relata o desenvolvimento e aplicacao de uma oficina apresentada para professores de Fisica do Ensino Medio com o intuito de se empregar o uso de um software de simulacao eletrica para o ensino dos conceitos basicos de circuitos eletricos resistivos. A oficina foi elaborada visando a utilizacao dos pressupostos e estrategias de aprendizagem ativa e levando-se em consideracao os conceitos da teoria aprendizagem significativa de David Ausubel. As atividades foram desenvolvidas de maneira pratica, utilizando o software de simulacao eletrica para ilustrar um cenario em que os alunos sao motivados a se engajarem mais ativamente em seu aprendizado. Como resultado desta oficina se evidencia um aumento na importância da utilizacao de novas tecnologias em sala de aula quando utilizadas de acordo com metodologias de ensino-aprendizagem que promovam uma participacao mais ativa dos alunos. http://dx.doi.org/10.18226/23185279.v3iss3p104

The paper deals with the extension of the concept of content and cocontent functions, known from the theory of nonlinear resistive circuits, to circuits with memristive elements. The connection between the (co)content and the area of the hysteresis loop of a memristive element is indicated. It is proved and demonstrated on examples that the area of the hysteresis loop of a one-port, composed entirely of memristive elements, equals the sum of the areas of the loops of individual memristive elements. It is also proved that the law of conservation of (co)content applies also to circuits with memristive elements.

In the present work we explore resistive circuits where the individual resistors are arranged in fractal-like patterns. These circuits have some of the characteristics typically found in geometric fractals, namely self-similarity and scale invariance. Considering resistive circuits as graphs, we propose a definition of self-similar circuits which mimics a self-similar fractal. General properties of the resistive circuits generated by this approach are investigated, and interesting examples are commented in detail. Specifically, we consider self-similar resistive series, tree-like resistive networks and Sierpinski's configurations with resistors., 9 pages, 15 figures

This study examines the causal reasoning that university students use to explain how dc circuits work. We analyze how students use the concepts of electric field and potential difference in their explanatory models of dc circuits, and what kinds of reasoning they use at the macroscopic and microscopic levels in their explanations. This knowledge is essential to help instructors design and implement new teaching approaches that encourage students to articulate the macroscopic and microscopic levels of description. A questionnaire with an emphasis on explanations was used to analyze students’ reasoning. In this analysis of students’ reasoning in the microscopic and macroscopic modeling processes in a dc circuit, we refer to epistemological studies of scientific explanations. We conclude that the student explanations fall into three main categories of reasoning. The vast majority of students employ an explanatory model based on simple or linear causality and on relational reasoning. Moreover, around a third of students use a relational reasoning that relates two magnitudes current and resistance or conductivity of the material, which is included in a macroscopic explanatory model based on Ohm’s law and the conservation of the current. In addition, few students situate the explanations at the microscopic level (charges or electrons) with unidirectional cause-effect reasoning. This study looks at a number of aspects that have been little mentioned in previous research at the university level, about the reasoning types students use when establishing macro-micro relationships and some possible difficulties with complex reasoning.

This chapter contains sections titled: Design of a Resistive Thevenin Source Design of a Coupling Circuit Design of a Pi Attenuator Problems

A new algorithm is proposed for finding all solutions of piecewise-linear resistive circuits using separable programming. In this algorithm, the problem of finding all solutions is formulated by a separable programming problem, and it is solved by the modified simplex method using the restricted-basis entry rule. Since the modified simplex method finds one solution per application, the proposed algorithm can find all solutions efficiently. Numerical examples are given to confirm the effectiveness of the proposed algorithm.

The research reported in this paper represents an in-depth examination of the finding from an earlier investigation that university students often do not develop a functional understanding of the concept of a complete circuit. Participants in this study included undergraduates in introductory and upper-division physics courses as well as graduate teaching assistants. Although the concept of a complete circuit is covered in the standard undergraduate curriculum, students in all three groups had difficulty in applying this concept to single-loop, resistive circuits. Students frequently did not apply the conservation of current when analyzing circuits containing more than one battery. Certain basic conceptual difficulties spanned all of the populations and even persisted after instruction in upper-division courses that involved analog electronics.

A simple and efficient method is proposed for finding all characteristic curves of piecewise-linear resistive circuits using the integer programming solver CPLEX. It is proved that all characteristic curves can be obtained by this method using the manual of CPLEX and the original paper where the algorithm used in CPLEX is proposed. Our method can be implemented easily without writing complex programs, and all characteristic curves are obtained by solving mixed integer programming problems only twice.

An efficient algorithm is proposed for finding all solutions of piecewise-linear (PWL) resistive circuits with high approximation accuracy, namely, circuits where the characteristics of PWL resistors are approximated by PWL functions with a very large number of segments. This algorithm is based on the LP test using the dual simplex method, the contraction method, and a special technique that makes the algorithm not require large memory space and not require copying tableaus. By numerical examples, it is shown that the proposed algorithm could find all solutions of a circuit where the number of PWL resistors is 4000 and the number of linear regions is 10 0004000.

A self-switching circuit and a resistive circuit are designed and implemented for vibration suppression with a piezo patch in this study. A numerical model is developed for a rectangular beam bonded with a pair of piezo patches. One piezo patch is used to excite the system, the other one being used for vibration damping. Optimal resistances are respectively determined for the resistive circuit and self-switching circuit, and a new switch law is proposed for the switching circuit. These two circuits are implemented in an experimental setup to verify the model. Experimental results show that the vibration of a clamped beam can be effectively damped by using the resistive circuit or switching circuit. Due to the fact that switching is not perfect in practice, the damping performance of the switching circuit is a little different from the simulated result.

Recently, efficient algorithms have been proposed for finding all characteristic curves of one-port piecewise-linear resistive circuits. Using these algorithms, a middle scale one-port circuit can be represented by a piecewise-linear resistor that is neither voltage nor current controlled. In this letter, an efficient algorithm is proposed for finding all dc operating points of piecewise-linear circuits containing such neither voltage nor current controlled resistors.

Recently, an efficient algorithm was proposed for finding all solutions of piecewise-linear (PWL) resistive circuits using the simplex method, which could solve a problem where the number of PWL resistors is 200 and the number of linear regions is 10/sup 200/. In this work, an improved version of this algorithm is proposed, which can be applied to a broader class of PWL resistive circuits and could solve problems where the number of PWL resistors is 500 and the number of linear regions is 10/sup 500/ in practical computation time.

This paper presents a novel approach to the study of electric circuits: utilizing three phase electric power systems to introduce students to the techniques of circuit analysis beyond Kirchhoff’s and Ohm’s Laws. The efficacy of the pedagogy is evaluated by comparison of student performance on DC circuits assessment quiz pre and post intervention and by comparison to circuit analysis methods used by experts. Also discusses is how the curriculum effects students qualitative and quantitative conceptions of the behavior of voltage and current in DC resistive circuits.

In this letter, an effective technique is proposed for improving the computational efficiency of the contraction-type LP test algorithm, which is an algorithm for finding all solutions of piecewise-linear resistive circuits. Using the proposed technique, all solutions of a large-scale problem, where the number of variables is 100 and the number of linear regions is 10100, could be found in less than 10 min using a 360 MHz computer. Copyright 2001 John Wiley & Sons, Ltd.

In this letter, the performance of the LP test algorithm, which is an algorithm for finding all solutions of piecewise-linear resistive circuits, is evaluated by numerical experiments. It is shown that the algorithm could find all solutions of large-scale problems (including those where the number of variables is 200-300 and the number of linear regions is 10 200 -10 300 ) in practical computation time.

An efficient and practical method is proposed for finding all solutions of piecewise-linear resistive circuits using integer programming. In this method, we formulate the problem of finding all solutions by a mixed integer programming problem, and solve it by a high-performance integer programming software such as GLPK, SCIP, or CPLEX. It is shown that the proposed method can be easily implemented without making complicated programs. It is also confirmed by numerical examples that the proposed method can find all solutions of medium-scale circuits in practical computation time.

This paper presents an efficient algorithm for finding all solutions of piecewise-linear resistive circuits. The algorithm uses two types of sign tests; one is a new test that is proposed in this paper, and the other is the test proposed by Yamamura and Ochiai (1992). The computational complexity of the new test is much smaller than that of Yamamura and Ochiai's test. These tests eliminate many linear regions that do not contain a solution. Therefore, the number of simultaneous linear equations to be solved is substantially reduced. The proposed algorithm is very simple and efficient. >

Building upon of a set of innovative hands-on laboratory courses developed at Virginia Tech (VT) known as Lab-in-a-Box (LiaB), LiaB is now being expanded to Virginia Community Colleges (VCCS) where faculty from VT and the VCCS are working to incorporate LiaB into the engineering and engineering technology programs. As implemented at VT, the students design, build, and test at home various d.c. and a.c. circuits using an inexpensive electronics and demonstrate the operation of these circuits in an open classroom environment. LiaB covers topics ranging from simple resistive circuits to filters and provides students a physical representation of models created in various circuit modeling software programs. Modifications to the way in which the students are engaged in the LiaB experiments have been instituted at three VCCS community colleges to tailor the laboratory experience to instructional environment at each school. Learning materials are under development, to support students to achieve a deeper depth of learning of the underlying circuit theory. Non-traditional dissemination avenues, such as podcasts and Flash tutorials, are being considered as a means to engage students in the learning process. Evaluation of the courses and learning materials and assessment of the learning outcomes at VT and at the three VCCS has recently begun.