Types for X10 Clocks

X10 is a modern language built from the ground up to handle future parallel systems, from multicore machines to cluster configurations. We take a closer look at a pair of synchronisation mechanisms: finish and clocks. The former waits for the termination of parallel computations, the latter allow multiple concurrent activities to wait for each other at certain points in time. In order to better understand these concepts we study a type system for a stripped down version of X10. The main result assures that well typed programs do not run into the errors identified in the X10 language reference, namely the ClockUseException. The study will open, we hope, doors to a more flexible utilisation of clocks in the X10 language.Comment: In Proceedings PLACES 2010, arXiv:1110.385

Deductive Verification of Parallel Programs Using Why3

The Message Passing Interface specification (MPI) defines a portable message-passing API used to program parallel computers. MPI programs manifest a number of challenges on what concerns correctness: sent and expected values in communications may not match, resulting in incorrect computations possibly leading to crashes; and programs may deadlock resulting in wasted resources. Existing tools are not completely satisfactory: model-checking does not scale with the number of processes; testing techniques wastes resources and are highly dependent on the quality of the test set. As an alternative, we present a prototype for a type-based approach to programming and verifying MPI like programs against protocols. Protocols are written in a dependent type language designed so as to capture the most common primitives in MPI, incorporating, in addition, a form of primitive recursion and collective choice. Protocols are then translated into Why3, a deductive software verification tool. Source code, in turn, is written in WhyML, the language of the Why3 platform, and checked against the protocol. Programs that pass verification are guaranteed to be communication safe and free from deadlocks. We verified several parallel programs from textbooks using our approach, and report on the outcome.Comment: In Proceedings ICE 2015, arXiv:1508.0459

Is there space to build one more transshipment terminal within Portuguese territory?

NSBE - UN

Evaluation of commercially available post-consumer recycled pet to produce bottles for mineral water

O Polietileno Tereftalato (PET) é o principal polímero para a produção de garrafas de água e refrigerantes, sendo cada vez mais importante, no contexto global, o combate ao desperdício e descarte através da reciclagem deste importante recurso. Neste trabalho, seis resinas processo mecânicos aprovados pela EFSA foram avaliadas. As propriedades de cor, viscosidade intrínseca, temperatura de fusão, concentração de benzeno, limoneno, oligómeros e substâncias não intencionalmente adicionadas (NIAS) foram avaliadas. No que toca à determinação das concentrações de Benzeno, Limoneno e Oligómeros, foram encontrados valores superiores comparativamente ao reportado em bibliografia. As concentrações obtidas foram de 30 – 410 μg kg-1 PET para o benzeno, 20 – 66 μg kg-1 PET para o limoneno; 52 – 78 mg kg-1 PET para o dímero e 999 – 1394 mg kg-1 PET para o trímero. A concentração de NIAS detetada nas resinas conduz a um nível de exposição estimado (considerando uma garrafa de 8,5 g e 0,3 L) inferior ao correspondente à Classe 3 de Cramer da abordagem TTC para o limite de risco toxicológico. A análise estatística dos dados pelo modelo paramétrico univariado agrupou as amostras em 3 sub-grupos de homogeneidade: o primeiro grupo compreende as amostras IN, NO e F, o segundo as amostras F, FBL e BA e o terceiro a amostra MO. A análise por componentes independentes (ICA) confirmou alguns dos resultados deste teste. Foi possível verificar a similaridade das amostras MO e BA pelos conteúdos em nonanal, F e FBL pelo etilhexilacetato, dodecano e o difenil éter e as amostras FBL e IN pelo farneceno. A amostra NO foi a única que não apresentou correlação com as restantes.Polyethylene terephthalate (PET) is the most important polymer for the production of bottles for water and soft drinks, being increasingly important globally to reduce waste by recycling this material. In this work, six PET resins from different mechanical recycling processes, with positive opinions from EFSA, were evaluated for the properties: color, intrinsic viscosity, melting temperature and for the concentration of benzene, limonene, oligomers, and non-intentionally added substances (NIAS). Regarding the determination of Benzene, Limonene, and Oligomers, the samples in study have higher concentration values than those found in the literature. The obtained concentrations are 30 – 410 μg kg-1 PET for benzene, 20 – 66 μg kg-1 PET, for limonene and 52 – 78 mg kg-1 PET for PET dimer and 999 – 1394 mg kg-1 PET for trimer. The unknowns and NIAS concentration detected in the resins, yield and estimated exposure levels (considering a bottle of 8,5 g and 0,3 L) lower than that corresponding to the Cramer Class 3 of TTC approach for toxicology risk. The statistical analysis by univariate approach grouped the samples into 3 subsets: one group including the samples IN, NO, and F, the second group including the samples F, FBL, and BA, and NO as the only sample in the third group. The ICA approach confirmed some results from the univariate model: it was found out that MO and BA correlate by nonanal, F and FBL by the ethylhexylacetate, dodecane and diphenyl ether, and FBL and IN by farnesene. NO showed no correlation with the remaining

An instance of the MIKADO migration model

In this document, we briefly describe the main contribution to the deliverable on experimenting with the implementation of most of the calculi considered in the project. First, we describe how two well known calculi for mobile processes KLAIM and Dπ have been implemented on the top of IMC. We then describe the implementation of the MiKO programming language, an instance of the parametric calculus introduced in the WP1 with the TyCO calculus as the content of the membrane itself. After this, we outline the description of the implementation of the abstract machine for an instance of the Kell Calculus that dedicates particular attention to the proof of its correctness. Our presentation ends with a discussion of the problem of implementing security membranes on the top of an execution platform

Nonrigid reconstruction of 3D breast surfaces with a low-cost RGBD camera for surgical planning and aesthetic evaluation

Accounting for 26% of all new cancer cases worldwide, breast cancer remains the most common form of cancer in women. Although early breast cancer has a favourable long-term prognosis, roughly a third of patients suffer from a suboptimal aesthetic outcome despite breast conserving cancer treatment. Clinical-quality 3D modelling of the breast surface therefore assumes an increasingly important role in advancing treatment planning, prediction and evaluation of breast cosmesis. Yet, existing 3D torso scanners are expensive and either infrastructure-heavy or subject to motion artefacts. In this paper we employ a single consumer-grade RGBD camera with an ICP-based registration approach to jointly align all points from a sequence of depth images non-rigidly. Subtle body deformation due to postural sway and respiration is successfully mitigated leading to a higher geometric accuracy through regularised locally affine transformations. We present results from 6 clinical cases where our method compares well with the gold standard and outperforms a previous approach. We show that our method produces better reconstructions qualitatively by visual assessment and quantitatively by consistently obtaining lower landmark error scores and yielding more accurate breast volume estimates

Online estimation of the hand-eye transformation from surgical scenes

Hand-eye calibration algorithms are mature and provide accurate transformation estimations for an effective camera-robot link but rely on a sufficiently wide range of calibration data to avoid errors and degenerate configurations. To solve the hand-eye problem in robotic-assisted minimally invasive surgery and also simplify the calibration procedure by using neural network method cooporating with the new objective function. We present a neural network-based solution that estimates the transformation from a sequence of images and kinematic data which significantly simplifies the calibration procedure. The network utilises the long short-term memory architecture to extract temporal information from the data and solve the hand-eye problem. The objective function is derived from the linear combination of remote centre of motion constraint, the re-projection error and its derivative to induce a small change in the hand-eye transformation. The method is validated with the data from da Vinci Si and the result shows that the estimated hand-eye matrix is able to re-project the end-effector from the robot coordinate to the camera coordinate within 10 to 20 pixels of accuracy in both testing dataset. The calibration performance is also superior to the previous neural network-based hand-eye method. The proposed algorithm shows that the calibration procedure can be simplified by using deep learning techniques and the performance is improved by the assumption of non-static hand-eye transformations.Comment: 6 pages, 4 main figure

Automated pick-up of suturing needles for robotic surgical assistance

Robot-assisted laparoscopic prostatectomy (RALP) is a treatment for prostate cancer that involves complete or nerve sparing removal prostate tissue that contains cancer. After removal the bladder neck is successively sutured directly with the urethra. The procedure is called urethrovesical anastomosis and is one of the most dexterity demanding tasks during RALP. Two suturing instruments and a pair of needles are used in combination to perform a running stitch during urethrovesical anastomosis. While robotic instruments provide enhanced dexterity to perform the anastomosis, it is still highly challenging and difficult to learn. In this paper, we presents a vision-guided needle grasping method for automatically grasping the needle that has been inserted into the patient prior to anastomosis. We aim to automatically grasp the suturing needle in a position that avoids hand-offs and immediately enables the start of suturing. The full grasping process can be broken down into: a needle detection algorithm; an approach phase where the surgical tool moves closer to the needle based on visual feedback; and a grasping phase through path planning based on observed surgical practice. Our experimental results show examples of successful autonomous grasping that has the potential to simplify and decrease the operational time in RALP by assisting a small component of urethrovesical anastomosis

FetReg2021: A Challenge on Placental Vessel Segmentation and Registration in Fetoscopy

Fetoscopy laser photocoagulation is a widely adopted procedure for treating Twin-to-Twin Transfusion Syndrome (TTTS). The procedure involves photocoagulation pathological anastomoses to regulate blood exchange among twins. The procedure is particularly challenging due to the limited field of view, poor manoeuvrability of the fetoscope, poor visibility, and variability in illumination. These challenges may lead to increased surgery time and incomplete ablation. Computer-assisted intervention (CAI) can provide surgeons with decision support and context awareness by identifying key structures in the scene and expanding the fetoscopic field of view through video mosaicking. Research in this domain has been hampered by the lack of high-quality data to design, develop and test CAI algorithms. Through the Fetoscopic Placental Vessel Segmentation and Registration (FetReg2021) challenge, which was organized as part of the MICCAI2021 Endoscopic Vision challenge, we released the first largescale multicentre TTTS dataset for the development of generalized and robust semantic segmentation and video mosaicking algorithms. For this challenge, we released a dataset of 2060 images, pixel-annotated for vessels, tool, fetus and background classes, from 18 in-vivo TTTS fetoscopy procedures and 18 short video clips. Seven teams participated in this challenge and their model performance was assessed on an unseen test dataset of 658 pixel-annotated images from 6 fetoscopic procedures and 6 short clips. The challenge provided an opportunity for creating generalized solutions for fetoscopic scene understanding and mosaicking. In this paper, we present the findings of the FetReg2021 challenge alongside reporting a detailed literature review for CAI in TTTS fetoscopy. Through this challenge, its analysis and the release of multi-centre fetoscopic data, we provide a benchmark for future research in this field

MiKO---Mikado Koncurrent Objects

The motivation for the Mikado migration model is to provide programming constructs for controlling code mobility that are as independent as possible from the particular programming language used to program the code. The main idea is to regard a domain (or site, or locality), where mobile code may enter or exit, as a membrane enclosing running processes, and offering services that have to be called for entering or exiting the domain. MiKO---Mikado Koncurrent Objects is a particular instance of this model, where the membrane is explicitly split in two parts: the methods defining the interface, and a process part describing the data for, and the behavior of, the interface. The talk presents the syntax, operational semantics, and type system of MiKO, together with an example. It concludes by briefly mentioning the implementation of a language based on the calculus