Towards a design-by-contract based approach for realizable connector-centric software architectures

Despite being a widely-used language for specifying software systems, UML remains less than ideal for software architectures. Architecture description languages (ADLs) were developed to provide more comprehensive support. However, so far the application of ADLs in practice has been impeded by at least one of the following problems: (i) advanced formal notations, (ii) lack of support for complex connectors, and (iii) potentially unrealizable designs. In this paper we propose a new ADL that is based on Design-by-Contract (DbC) for specifying software architectures. While DbC promotes a formal and precise way of specifying system behaviours, it is more familiar to practising developers, thus allowing for a more comfortable way of specifying architectures than using process algebras. Furthermore, by granting connectors a first-class status, our ADL allows designers to specify not only simple interaction mechanisms as connectors but also complex interaction protocols. Finally, in order to ensure that architectural designs are always realizable we eliminate potentially unrealizable constructs in connector specifications (the connector “glue”)

What to Fix? Distinguishing between design and non-design rules in automated tools

Technical debt---design shortcuts taken to optimize for delivery speed---is a critical part of long-term software costs. Consequently, automatically detecting technical debt is a high priority for software practitioners. Software quality tool vendors have responded to this need by positioning their tools to detect and manage technical debt. While these tools bundle a number of rules, it is hard for users to understand which rules identify design issues, as opposed to syntactic quality. This is important, since previous studies have revealed the most significant technical debt is related to design issues. Other research has focused on comparing these tools on open source projects, but these comparisons have not looked at whether the rules were relevant to design. We conducted an empirical study using a structured categorization approach, and manually classify 466 software quality rules from three industry tools---CAST, SonarQube, and NDepend. We found that most of these rules were easily labeled as either not design (55%) or design (19%). The remainder (26%) resulted in disagreements among the labelers. Our results are a first step in formalizing a definition of a design rule, in order to support automatic detection.Comment: Long version of accepted short paper at International Conference on Software Architecture 2017 (Gothenburg, SE

Evaluating Middle School English Language Learners’ Science and Literacy Proficiency

The academic success and English proficiency of ELL students are receiving more attention as a result of the growing number of ELL students and the demand for accountability and assessment in education. It is widely accepted that ELL students struggle on state standardized tests because they lack the cognitive academic language abilities needed to succeed on extensive subject evaluations (Thakkar, 2013). According to Abedi and Dietel, ELLs\u27 academic performance lags behind that of other segments of population, and the attainment gap reduces only slightly over time (2004). The NWEA archival data of 6th, 7th, and 8th grade students who attended a Midwest area middle school in 2018-2019 educational year was used to investigate the question of whether or not middle school ELL students’ academic achievement improved in integrated science during one year of instruction while becoming more English language proficient, and improved in integrated science significantly more than the native speakers’ achievement in science after both groups completed a year of science instruction.. The data were used to analyze trends over time and variation in changes over time among groups of individuals in terms of English language and science achievements. Paired t-test and analysis of variances were used to determine if there was a relationship between science achievement and English language proficiency. The results indicated that there was a significant improvement in academic achievement of ELL students in science during one year of instruction while they were becoming more English language proficient, and ELL students’ academic achievement in science did not improve significantly more than the native speakers’ achievement after both groups completed a year of science instruction. Findings may be used to develop strategies to improve English language skills of ELL students of the targeted school settings. Improvement in English language skills may allow ELL students to succeed in all subject areas

Electrochemical Aptasensor for Detection of Dopamine

This work presents a proof of concept of a novel, simple, and sensitive method of detection of dopamine, a neurotransmitter within the human brain. We propose a simple electrochemical method for the detection of dopamine using a dopamine-specific aptamer labeled with an electrochemically active ferrocene tag. Aptamers immobilized on the surface of gold screen-printed gold electrodes via thiol groups can change their secondary structure by wrapping around the target molecule. As a result, the ferrocene labels move closer to the electrode surface and subsequently increase the electron transfer. The cyclic voltammograms and impedance spectra recorded on electrodes in buffer solutions containing different concentration of dopamine showed, respectively, the increase in both the anodic and cathodic currents and decrease in the double layer resistance upon increasing the concentration of dopamine from 0.1 to 10 nM L-1. The high affinity of aptamer-dopamine binding (KD ≈ 5 nM) was found by the analysis of the binding kinetics. The occurrence of aptamer-dopamine binding was directly confirmed with spectroscopic ellipsometry measurements

On asymptotic distributions of exceedance statistics

AbstractIn this study, two independent samples X1,X2,…,Xn and Y1,Y2,…,Ym with respective distribution functions F and Q are considered. The joint asymptotic distributions of exceedance statistics defined as the number of Y observations falling into a random interval of order statistics constructed from the X sample is investigated. The results can be used in the context of a two-sample problem