Software verification and validation

In software project management, software testing, and software engineering, verification and validation (V&V) is the process of checking that a software system meets specifications and requirements so that it fulfills its intended purpose. It may also be referred to as software quality control. It is normally the responsibility of software testers as part of the software development lifecycle. In simple terms, software verification is: "Assuming we should build X, does our software achieve its goals without any bugs or gaps?" On the other hand, software validation is: "Was X what we should have built? Does X meet the high-level requirements?" Definitions Verification and validation are not the same thing, although they are often confused. Boehm succinctly expressed the difference as

Verification: Are we building the product right?
Validation: Are we building the right product?

"Building the product right" checks that the specifications are correctly implemented by the

Foot-Interfaces Control and Human-Robot Interaction in Four-Handed Manipulation

Jacob Hernandez Sanchez

Humans have a great capacity to perform complex manipulations. However, there are many tasks for which two hands are not enough, such as in surgery. For such tasks, a dyad of people is required. However, when not used to work together, a dyad collaboration can be intermittent, slow and prone to misunderstandings if relied solely on verbal cues. The current PhD thesis report concerns the design and control of foot interfaces to enable solo four-handed manipulations. In the first part, we present the platform design in five DoF, with position mapping and haptic force feedback. We tackle the known issue of fatigue when using position mapping, by partially compensating for the dynamics of the leg. Finally, we perform a series of feasibility validations on bipedal teleoperation in 3 and 4 and 5 DoF. In the second part, a behavioural study investigates a symmetric bipedal holding and transport of an object while working on it with the hands. This study sheds light to the human capacity to use the redundancy given by augmentation with the feet, to assist the task of the hands. We investigate the effect of shared-control for lower limb teleoperation. Two modalities are used: 1. synergistic control of two robotic arms with one foot, 2. force assistance. We evaluate these strategies in terms of objective and subjective metrics, such as physical and cognitive workload and fluency.Aiming at enabling individualized foot dexterous control, in the third part of the thesis, we addressed the problem of bio-mechanical coupling of foot rotations. This is done by detecting intention to grasp, and selectively easing this action while haptically constraining the foot gestures for tool alignment. A user study was conducted to evaluate our proposed approach in a surgical laparoscopic gripper.In the fourth and final part, we focus on investigating more demanding tasks for the feet, as well as the coordinated control of four hands, during hybrid-robotic laparoscopic surgery. One foot controls a camera, while the other one performs a grasping task. Noteworthy is that all four-arms can be controlled simultaneously. For easing the solo surgical task, we design haptic assistance, for autonomous grasping operated by the foot. Finally, we perform a systematic behavioural study to understand the effect of our haptic-shared-control, along with an assistance modality for camera tool-tracking. We cover uni-pedal, bipedal and four-handed task scenarios. Our main conclusion is that foot gestures can be conditioned with haptic feedback, to effectively control multiple degrees of freedom of a supernumerary robotic arm. Thereby enabling four-arm simultaneous manipulations. This is done specifically by leveraging 1. a foot kinesthetic haptic platform that allows for the use of two feet, 2. leg compensation, and virtual assistive impedance, which are useful to increase comfort and alleviate fatigue. 3. Hybridization of control mappings for foot gestures, with limited range of motion and oblique axes of rotation, 4. Haptic shared-control strategies for prehensile force assistance, coordination assistance, and DoF-individuation assistance. We found that robotic assistance is highly appreciated, and has an important role in simplifying four-handed tasks. Indeed, these are instrumental considerations to enable a more fluent, less demanding, and more performant interaction, in tasks where the feet are supplementing the task of hands.

EPFL2022

A fully joint Bayesian quantitative trait locus mapping of human protein abundance in plasma

Anthony Christopher Davison, Jörg Hager, Radu Popescu, Hélène Ruffieux

Molecular quantitative trait locus (QTL) analyses are increasingly popular to explore the genetic architecture of complex traits, but existing studies do not leverage shared regulatory patterns and suffer from a large multiplicity burden, which hampers the detection of weak signals such as trans associations. Here, we present a fully multivariate proteomic QTL (pQTL) analysis performed with our recently proposed Bayesian method LOCUS on data from two clinical cohorts, with plasma protein levels quantified by mass-spectrometry and aptamer-based assays. Our two-stage study identifies 136 pQTL associations in the first cohort, of which >80% replicate in the second independent cohort and have significant enrichment with functional genomic elements and disease risk loci. Moreover, 78% of the pQTLs whose protein abundance was quantified by both proteomic techniques are confirmed across assays. Our thorough comparisons with standard univariate QTL mapping on (1) these data and (2) synthetic data emulating the real data show how LOCUS borrows strength across correlated protein levels and markers on a genome-wide scale to effectively increase statistical power. Notably, 15% of the pQTLs uncovered by LOCUS would be missed by the univariate approach, including several trans and pleiotropic hits with successful independent validation. Finally, the analysis of extensive clinical data from the two cohorts indicates that the genetically-driven proteins identified by LOCUS are enriched in associations with low-grade inflammation, insulin resistance and dyslipidemia and might therefore act as endophenotypes for metabolic diseases. While considerations on the clinical role of the pQTLs are beyond the scope of our work, these findings generate useful hypotheses to be explored in future research; all results are accessible online from our searchable database. Thanks to its efficient variational Bayes implementation, LOCUS can analyze jointly thousands of traits and millions of markers. Its applicability goes beyond pQTL studies, opening new perspectives for large-scale genome-wide association and QTL analyses.

PUBLIC LIBRARY SCIENCE2020

Counterexample-Guided Focus

The automated inference of quantified invariants is considered one of the next challenges in software verification. The question of the right precision-efficiency tradeoff for the corresponding program analyses here boils down to the question of the right treatment of disjunction below and above the universal quantifier. In the closely related setting of shape analysis one uses the focus operator in order to adapt the treatment of disjunction (and thus the efficiency-precision tradeoff) to the individual program statement. One promising research direction is to design parameterized versions of the focus operator which allow the user to fine-tune the focus operator not only to the individual program statements but also to the specific verification task. We carry this research direction one step further. We fine-tune the focus operator to each individual step of the analysis (for a specific verification task). This fine-tuning must be done automatically. Our idea is to use counterexamples for this purpose. We realize this idea in a tool that automatically infers quantified invariants for the verification of a variety of heap-manipulating programs.