Batch processing with interval graph compatibilities between tasks

We analyze batch-scheduling problems that arise in connection with certain industrial applications. The models concern processing on a single max-batch machine with the additional feature that the tasks of the same batch have to be compatible. Compatibility is a symmetric binary relation—the compatible pairs are described with an undirected “compatibility graph”, which is often an interval graph according to some natural practical conditions that we present. We consider several models with varying batch capacities, processing times or compatibility graphs. We summarize known results, and present a min-max formula and polynomial time algorithms.     

The catwalk task: Reflections and synthesis: Part 2

In this article we recount our experiences with a series of encounters with the catwalk task and reflect on the professional growth that these opportunities afforded. First, we individually reflect on our own mathematical work on the catwalk task. Second, we reflect on our experiences working with a group of community college students on the catwalk task and our interpretations of their mathematical thinking. In so doing we also detail a number of innovative and novel student-generated representations of the catwalk photos. Finally, we each individually reflect on the entire experience with the catwalk problem, as mathematics learners, as teachers, and as professionals.     

Onium salt supported peptide synthesis

Task specific ionic liquids and onium salts have been used as soluble supports for peptide synthesis. These new supports combine easy monitoring, high loading capacities, large scale preparation, and homogeneous kinetics characteristics while keeping advantages of solid-phase synthesis including easy purification and workup. Careful structural design of these supports allowed for fine tuning of physical properties leading to better yields, kinetics, and purities.     

A microextraction procedure based on a task‐specific ionic liquid for the separation and preconcentration of lead ions from red lipstick and pine leaves

First, the extraction and preconcentration of ultratrace amounts of lead(II) ions was performed using microliter volumes of a task‐specific ionic liquid. The remarkable properties of ionic liquids were added to the advantages of microextraction procedure. The ionic liquid used was trioctylmethylammonium thiosalicylate, which formed a lead thiolate complex due to the chelating effect of the ortho‐positioned carboxylate relative to thiol functionality. So, trioctylmethylammonium thiosalicylate played the roles of both chelating agent and extraction solvent simultaneously. Hence, there is no need to use a ligand. The main parameters affecting the efficiency of the method were investigated and optimized. Under optimized conditions, this approach showed a linear range of 2.0–24.0 ng/mL with a detection limit of 0.0010 ng/mL. The proposed method was applied to the extraction and preconcentration of lead from red lipstick and pine leaves samples prior to electrothermal atomic absorption spectroscopic determination.     

Focusing on the Needs: Experiences of Developing a Data Science Program

Donoho’s article “50 Years of Data Science” is a well-thought explanation of a newly developed discipline called “data science.” In this article, we examine his explanations and suggestions about data science, follow-up on some of the issues he mentioned, and share our experiences in developing a data science curriculum and the teaching of related courses.     

A hybrid adaptively genetic algorithm for task scheduling problem in the phased array radar

A phased array radar (PAR) is used to detect new targets and update the information of those detected targets. Generally, a large number of tasks need to be performed by a single PAR in a finite time horizon. In order to utilize the limited time and the energy resources, it is necessary to provide an efficient task scheduling algorithm. However, the existing radar task scheduling algorithms can't be utilized to release the full potential of the PAR, because of those disadvantages such as full PAR task structure ignored, only good performance in one aspect considered and just heuristic or the meta-heuristic method utilized. Aiming at above issues, an optimization model for the PAR task scheduling and a hybrid adaptively genetic (HAGA) algorithm are proposed. The model considers the full PAR task structure and integrates multiple principles of task scheduling, so that multi-aspect performance can be guaranteed. The HAGA incorporates the improved GA to explore better solutions while using the heuristic task interleaving algorithm to utilize wait intervals to interleave subtasks and calculate fitness values of individuals in efficient manners. Furthermore, the efficiency and the effectiveness of the HAGA are both improved by adopting chaotic sequences for the population initialization, the elite reservation and the mixed ranking selection, as well as designing the adaptive crossover and the adaptive mutation operators. The simulation results demonstrate that the HAGA possesses merits of global exploration, faster convergence, and robustness compared with three state-of-art algorithms—adaptive GA, hybrid GA and highest priority and earliest deadline first heuristic (HPEDF) algorithm.     

The Effect of Speaking Sample Duration on Determination of Habitual Pitch

The purpose of this study was to investigate if there was an effect of duration of speaking on determination of habitual pitch. Five speaking periods commonly used to elicit habitual pitch in clinical voice evaluations were compared (1, 5, 15, 30, and 60 seconds). Thirty female speakers with normal voices participated. Results of a within-subject univariate F-test revealed a statistically significant (p < 0.001) difference in habitual pitch among the speaking periods. Habitual pitch for the 1-second and 60-second speaking periods were found to be statistically significantly (p < 0.05) different than all remaining speaking periods, and the habitual pitch for the 30-second speaking period was found to be statistically significantly (p < 0.05) different than 60-second speaking period. Implications for the use of various speaking durations when determining habitual pitch are discussed, as is the possibility of a speaking duration effect on determination of other pitch-related voice parameters.     

Developing and refining a framework for mathematical and linguistic complexity in tasks related to rates of change

We present and develop a preliminary framework for describing the relationship between the mathematical and linguistic complexity of instructional tasks used in secondary mathematics. The initial framework was developed through a review of relevant literature. It was refined by examining how 4 ninth grade mathematics teachers of linguistically diverse groups of students described the linguistic and mathematical complexity of a set of tasks from their curriculum unit on linear functions. We close by presenting our refined framework for describing the interaction of linguistic complexity and mathematical complexity in curriculum materials, and discuss potential uses of this framework in the design of more accessible classroom learning environments for linguistically diverse students.     

A task that elicits reasoning: A dual analysis

This paper reports on the forms of reasoning elicited as fourth grade students in a suburban district and sixth grade students in an urban district worked on similar tasks involving reasoning with the use of Cuisenaire rods. Analysis of the two data sets shows similarities in the reasoning used by both groups of students on specific tasks, and the tendency of a particular task to elicit numerous forms of reasoning in both groups of students. Attributes of that task and ways that those attributes can be replicated in other domains may have implications in the teaching of early reasoning.