Prototyping Dynamic Software Product Lines to evaluate run-time reconfigurations

Dynamic Software Product Lines (DSPL) encompass systems that are capable of modifying their own behavior with respect to changes in their operating environment by using run-time reconfigurations. A failure in these reconfigurations can directly impact the user experience since the reconfigurations are performed when the system is already under the users control. In this work, we prototype a Smart Hotel DSPL to evaluate the reliability-based risk of the DSPL reconfigurations, specifically, the probability of malfunctioning (Availability) and the consequences of malfunctioning (Severity). This DSPL prototype was performed with the participation of human subjects by means of a Smart Hotel case study which was deployed with real devices. Moreover, we successfully identified and addressed two challenges associated with the involvement of human subjects in DSPL prototyping: enabling participants to (1) trigger the run-time reconfigurations and to (2) understand the effects of the reconfigurations. The evaluation of the case study reveals positive results regarding both Availability and Severity. However, the participant feedback highlights issues with recovering from a failed reconfiguration or a reconfiguration triggered by mistake. To address these issues, we discuss some guidelines learned in the case study. Finally, although the results achieved by the DSPL may be considered satisfactory for its particular domain, DSPL engineers must provide users with more control over the reconfigurations or the users will not be comfortable with DSPLs.     

Visibility-preserving convexifications using single-vertex moves

Devadoss asked: (1) can every polygon be convexified so that no internal visibility (between vertices) is lost in the process? Moreover, (2) does such a convexification exist, in which exactly one vertex is moved at a time (that is, using single-vertex moves)? We prove the redundancy of the “single-vertex moves” condition: an affirmative answer to (1) implies an affirmative answer to (2). Since Aichholzer et al. recently proved (1), this settles (2).     

Leveraging BPMN particularities to improve traceability links recovery among requirements and BPMN models

Requirements Engineering - Traceability links recovery (TLR) has been a topic of interest for many years. However, TLR approaches are based on the latent semantics of the software artifacts, and...     

Influence of grating parameters on the linewidths of external-cavity diode lasers

We investigate experimentally the influence of the grating reflectivity, grating resolution, and diode facet antireflection (AR) coating on the intrinsic linewidth of an external-cavity diode laser built with a diffraction grating in a Littrow configuration. Grating lasers at 399, 780, and 852 nm are determined to have typical linewidths between 250 and 600 kHz from measurements of their frequency noise power spectral densities. The linewidths are little affected by the presence of an AR coating on the diode facet but narrow as the grating reflectivity and grating resolution are increased, with the resolution exerting a greater effect. We also use frequency noise measurements to characterize a laser mount with improved mechanical stability.     

Handling nonconforming individuals in search-based model-driven engineering: nine generic strategies for feature location in the modeling space of the meta-object facility

Software and Systems Modeling - Lately, the model-driven engineering community has been paying more attention to the techniques offered by the search-based software engineering community. However,...     

Modelling of mercury transport and transformation processes in the Idrijca and Soca river system

In the town of Idrija, Slovenia, the world's second largest mercury mine was active for 500 years and about 37,000 tons of mercury has been lost in the environment. Mercury is still drained from soil, riverbed and floodplains and transported with the Idrijca and Soca Rivers to the Gulf of Trieste. A part of inorganic mercury is methylated either in the river system, or later in the coastal area, and, due to its bioaccumulation and biomagnification represents potential danger to human health. A 1-D aquatic model MeRiMod was used to simulate hydrodynamics and sediment transport in the river system from Idrija to the Soca River mouth. Transport of particle bound and dissolved mercury as well as potential net methylation of mercury in the river system was simulated. The simulation of an observed flood wave with 20-year recurrence period was performed in order to validate the model. Methylation was simulated at lower discharges, as higher methylation rates occur in such conditions. The measurement data and the MeRiMod model were also used to establish a historical mercury mass balance of the Idrijca and Soca Rivers catchment. Sediment core data from the Gulf of Trieste and the measured concentrations from floodplains were used to verify and calibrate the model. Simulations of different high discharges were performed as most of the transport of particulate mercury occurs within flood wave conditions. Compared to the measurements, the results of the model showed an agreement within an order of magnitude, for the transport of total mercury mostly within a factor of 4, and for the methylation within a factor of 5. However, proper trends of the phenomena were obtained by simulations. The combination of modelling and measurements has resulted in some interesting conclusions about the phenomenon of the transport and transformations of mercury in the observed river system.     

High incidence of chromosome 8 monosomy and chromosome 7 trisomy in prostatic primary tumor and its related lymphatic metastasis. Preliminary results

SETTING: Chest Clinic, University Teaching Hospital, Zambia. OBJECTIVE: To study the pre-diagnosis economic impact, burden, and barriers to care-seeking for tuberculosis patients in urban Zambia. DESIGN: In-depth interviews conducted over a 9-week period with adult in-patients and out-patients registering with new pulmonary tuberculosis; data analysis using Epi Info. RESULTS: Interviews were completed by 202 patients: 64% normally worked, but 31% stopped due to their tuberculosis, with an average of 48 days off. The mean duration of illness prior to their tuberculosis registration was 63 days, with 64% of patients delaying in presenting to the Chest Clinic. Of these, 38% blamed money shortages for their delay. In seeking diagnosis, patients incurred a mean total cost equivalent to 127% of their mean monthly income (pounds sterling UK 40 [$US 59]); direct expenditures represented 60% of this cost. In addition, patients lost, on average, 18 work days prior to diagnosis. Care-givers incurred costs equivalent to 31% of the mean monthly income (pounds sterling UK 10 [$US 15]). CONCLUSION: The economic burden of tuberculosis on patients creates barriers to prompt diagnosis which may lead to continuing transmission of the infection. Important economic barriers include transportation expenditure, cost of 'special food', and lost income. These barriers may be reduced through interventions that reduce the number of health encounters, travel distances and duration of illness before diagnosis.     

Autonomic Computing through Reuse of Variability Models at Runtime: The Case of Smart Homes

Our research shows that autonomic behavior can be achieved by leveraging variability models at runtime. In this way, the modeling effort made at design time is not only useful for producing the system but also provides a richer semantic base for autonomic behavior during execution. The use of variability models at runtime brings new opportunities for autonomic capabilities by reutilizing the efforts invested at design time. Our proposed approach has two aspects: reuse of design knowledge to achieve AC and reuse of existing model-management technologies at runtime. We developed the Model-Based Reconfiguration Engine (MoRE) to implement model-management operations. Our research demonstrates the approach's feasibility for smart homes, especially for self-healing and -configuring capabilities.     

Enhancing software model encoding for feature location approaches based on machine learning techniques

Software and Systems Modeling - Feature location is one of the main activities performed during software evolution. In our previous works, we proposed an approach for feature location in models...