bluuebunny/crossref_metadata_2025 huggingface dataset:
Is one-stop surgery for carpal tunnel syndrome safe? A retrospective long-term follow-up study in a neurosurgical unit in Copenhagen
Authors: Jørgensen Louise Møller , Piil Karin , Bashir Asma , Larsen Morten Bo , Poggenborg Pamela Santiago , Bjørck Sebastian , Fugleholm Kåre
Published: September 2017

Objectives

The aim of this study was to evaluate one-stop surgery (OSS) for carpal tunnel syndrome (CTS) regarding symptom relief and patient satisfaction. OSS in our setting means only one visit to the hospital for surgery and no hospital appointments for preassessment or follow-up. We hypothesised that relief of symptoms with OSS is comparable with that in non-OSS patients reported in the literature.

Design

This is a long-term retrospective follow-up study (56.5 months) of 1003 patients referred for CTS and discharged with or without surgery from an OSS clinic. Of the original cohort, 671 patients completed the long-term follow-up telephone interview.

Results

Two-thirds of the patients were free of even minor symptoms following surgery. The symptom relief and patient satisfaction in this study were comparable with results in non-OSS patients reported in the literature.

Conclusion

The implementation of a clinical pathway and OSS for the management of CTS was safe with good long-term symptom relief and high patient satisfaction.
Association between mothers’ screening uptake and daughters’ HPV vaccination: a quasi-experimental study on the effect of an active invitation campaign
Authors: Venturelli Francesco , Baldacchini Flavia , Campari Cinzia , Perilli Cinzia , Pascucci Maria Grazia , Finarelli Alba Carola , Moscara Luigi , Rossi Paolo Giorgi
Published: September 2017

Objectives

In Emilia-Romagna, the Human Papillomavirus (HPV) vaccination campaign started in 2008 offering free vaccines for 1996 and 1997 cohorts. Systematic active invitation was implemented for the 1997 cohort. Our study aimed at measuring the impact of the active invitation campaign on HPV vaccine coverage and on coverage inequalities in 11-year-old girls. Second, we evaluated the effect of the HPV vaccination campaign on participation in cervical cancer screening by mothers of target girls.

Methods

We collected information on vaccination status for girls residing in Reggio Emilia in 2008 and mothers’ screening history, before and after the 2008 vaccination campaign. Log-binomial regression models were performed to estimate Relative Risk (RR) and 95% confidence intervals (CIs) of being vaccinated as regarded citizenship, siblings, mothers’ education, marital status and screening history, stratified by birth cohort. We also calculated RR of receiving a Pap test after the vaccination campaign as regarded education, daughter’s cohort and mothers' decision to have their daughter vaccinated. Interaction between education and cohort in mothers overdue for Pap testing was calculated.

Results

Vaccination coverage was 46.3% for the uninvited cohort (1046/2260) and 77.9% for the invited cohort (1798/2307). In the uninvited cohort, daughters’ vaccination showed association with mothers’ education (8 to 11 years of education vs. graduated mothers, RR 1.61 95% CI 1.14–2.28), citizenship (foreigners vs. Italians, RR 0.45 95% CI 0.37–0.56) and screening history (regular vs. non-participant; RR 1.72 95% CI 1.26–2.36). In the invited cohort, only a slight association with screening history persisted (regular vs. non-participant; RR 1.20 95% CI 1.04–1.40). Highly educated under-screened mothers of the invited cohort showed a higher probability of receiving a Pap test after the vaccination campaign period (RR 1.27 95% CI 1.04–1.56) compared with those not invited,

Conclusion

Active invitation could increase overall HPV immunisation coverage and reduce socio-demographic inequalities and the association with mothers' screening participation.
Is local anaesthesia a favourable approach for transcatheter aortic valve implantation? A systematic review and meta-analysis comparing local and general anaesthesia
Authors: Ehret Constanze , Rossaint Rolf , Foldenauer Ann Christina , Stoppe Christian , Stevanovic Ana , Dohms Katharina , Hein Marc , Schälte Gereon
Published: September 2017

Objectives

We conducted a systematic review and meta-analysis to identify the potential favourable effects of local anaesthesia plus sedation (LAS) compared with general anaesthesia (GA) in transcatheter aortic valve implantation (TAVI).

Methods

Electronic databases (PubMed/Medline, Embase, Cochrane Central Register of Controlled Trials) and the reference lists of eligible publications were screened for randomised controlled trials (RCTs) and observational studies published between 1 January 2006 and 26 June 2016 that compare LAS to GA in an adult study population undergoing TAVI. We conducted study quality assessments using the Cochrane risk of bias tool and structured the review according to PRISMA. A meta-analysis calculating the pooled risk ratios (RRs) and mean differences (MDs) with 95% confidence intervals (CIs) under the assumption of a random-effects model was performed. Statistical heterogeneity was evaluated using the I² statistic and Cochran’s Q-test.

Results

After database screening, one RCT and 19 observational studies were included in the review. We found no differences between LAS and GA in terms of 30-day mortality, in-hospital mortality and other endpoints that addressed safety and complication rates. LAS was associated with a shorter ICU and hospital stay and with lower rates of catecholamine administration and red blood cell transfusion. New pacemaker implantations occurred more frequently under LAS. The overall conversion rate from LAS to GA was 6.2%.

Conclusion

For TAVI, both LAS and GA are feasible and safe. LAS may have some benefits such as increased haemodynamic stability and shorter hospital and ICU stays, but it does not impact 30-day mortality. Since there is a paucity of randomised trial data and the findings are mainly based on observational study data, this review should be considered as a hypothesis-generating article for subsequent RCTs that are required to confirm the potential favourable effects we detected for LAS.

Registration number

CRD42016048398 (PROSPERO).
Cost-effectiveness of milk powder fortified with potassium to decrease blood pressure and prevent cardiovascular events among the adult population in China: a Markov model
Authors: Dainelli Livia , Xu Tingting , Li Min , Zimmermann Diane , Fang Hai , Wu Yangfeng , Detzel Patrick
Published: September 2017

Objective

To model the long-term cost-effectiveness of consuming milk powder fortified with potassium to decrease systolic blood pressure (SBP) and prevent cardiovascular events.

Design

A best case scenario analysis using a Markov model was conducted.

Participants

8.67% of 50–79 year olds who regularly consume milk in China, including individuals with and without a prior diagnosis of hypertension.

Intervention

The model simulated the potential impact of a daily intake of two servings of milk powder fortified with potassium (+700 mg/day) vs the consumption of a milk powder without potassium fortification, assuming a market price equal to 0.99 international dollars (intl$; the consumption of a milk powder without potassium fortification, assuming a market price equal to intl$0.99 for the latter and to intl$1.12 for the first (+13.13%). Both deterministic and probabilistic sensitivity analyses were conducted to test the robustness of the results.

Main outcome measures

Estimates of the incidence of cardiovascular events and subsequent mortality in China were derived from the literature as well as the effect of increasing potassium intake on blood pressure. The incremental cost-effectiveness ratio (ICER) was used to determine the cost-effectiveness of a milk powder fortified with potassium taking into consideration the direct medical costs associated with the cardiovascular events, loss of working days and health utilities impact.

Results

With an ICER equal to int$4711.56 per QALY (quality-adjusted life year) in the best case scenario and assuming 100% compliance, the daily consumption of a milk powder fortified with potassium shown to be a cost-effective approach to decrease SBP and reduce cardiovascular events in China. Healthcare savings due to prevention would amount to intl$8.41 billion. Sensitivity analyses showed the robustness of the results.

Conclusion

Together with other preventive interventions, the consumption of a milk powder fortified with potassium could represent a cost-effective strategy to attenuate the rapid rise in cardiovascular burden among the 50–79 year olds who regularly consume milk in China.
Vitamin D status in tuberculosis patients with diabetes, prediabetes and normal blood glucose in China: a cross-sectional study
Authors: Zhao Xin , Yuan Yanli , Lin Yan , Zhang Tiejuan , Ma Jianjun , Kang Wanli , Bai Yunlong , Wang Yunlong , Shao Hongshan , Dlodlo Riitta A , Harries Anthony D
Published: September 2017

Objective

The association between tuberculosis (TB), diabetes mellitus (DM) and vitamin D status is poorly characterised. We therefore: (1) determined vitamin D status in patients with TB in relation to whether they had normal fasting blood glucose (FBG), pre-DM or DM and (2) assessed whether baseline characteristics in patients with TB, including their DM status, were associated with vitamin D deficiency.

Methods

In patients with TB consecutively attending six clinics or hospitals in China, we measured 25-hydroxycholecalciferol (25-(OH)D3) at the time of registration using electrochemiluminescence in a COBASE 601 Roche analyser by chemiluminescence immunoassay. Data analysis was performed using the χ2test, ORs and multivariate logistic regression.

Results

There were 306 eligible patients with TB, including 96 with smear positive pulmonary TB, 187 with smear negative pulmonary TB and 23 with extrapulmonary TB. Of these, 95 (31%) had normal blood glucose, 83 (27%) had pre-DM and 128 (42%) had DM. Median serum vitamin D levels were 16.1 ng/mL in patients with TB with normal FBG, 12.6 ng/mL in patients with TB with pre-DM and 12.1 ng/mL in patients with TB with DM (p<0.001). The study highlighted certain baseline characteristics associated with vitamin D deficiency (25-(OH)D3<20 ng/mL). After adjusting for confounders, serum vitamin D deficiency was significantly more common in patients being registered in the cold season (November to April) (p=0.006) and in those with DM (p=0.003).

Conclusion

Vitamin D levels are lower in patients with TB with pre-DM and DM and are also affected by certain baseline characteristics that include being registered in the cold season and having DM. TB programmes need to pay more attention to vitamin D status in their patients, especially if there is coexisting pre-DM or DM.
TheBrain Gamesstudy: protocol for a randomised controlled trial of computerised cognitive training for preventing mental illness in adolescents with high-risk personality styles
Authors: Mewton Louise , Hodge Antoinette , Gates Nicola , Visontay Rachel , Teesson Maree
Published: September 2017

Introduction

A broad range of mental disorders are now understood as aberrations of normal adolescent brain development. In both adolescents and adults, executive dysfunction has been implicated across a range of mental illnesses, and enhancing executive functioning may prove to be a useful prevention strategy for adolescents at risk for a range of psychopathology.

Methods and analysis

This study will consist of a double-blind, randomised controlled trial with a 12-month follow-up period. Participants will consist of 200 people aged 16–24 years who are at risk for a range of mental disorders based on personality risk factors, but have not experienced a lifetime mental illness as determined by a structured diagnostic interview. Participants will be randomly allocated to either an intervention group who complete an online cognitive training programme specifically targeting executive functioning ability or a control group who complete an online cognitive training programme that has limited executive functioning training potential. Superiority of the executive functioning training programme compared with the control training programme will be assessed at baseline, post-training and at 3-month, 6-month and 12-month follow-up. All assessments will be conducted online. The primary outcome of the study will be general psychopathology as measured by the Strengths and Difficulties Questionnaire. Secondary outcomes will include executive functioning ability, day-to-day functioning and alcohol consumption. All analyses will be undertaken using mixed-model repeated measures analysis of variance with planned contrasts.

Ethics and dissemination

Ethics approval has been obtained from the University of New South Wales Human Research Ethics Committee (HC15094). Results of the trial immediately post-treatment and at 12 months follow-up will be submitted for publication in peer-reviewed journals.

Trial registration number

ACTRN12616000127404; Pre-results.
Maydis Stigma Elicits Analgesia and Blocks Edema in Mice and Inhibits Inflammation in Macrophages
Authors: Jeong Yun Hee , Oh You-Chang , Cho Won-Kyung , Yang Hye Jin , Ma Jin Yeul
Published: September 2017

Maydis Stigma (MS) is an herb traditionally used in many parts of the world. Previous studies have reported that MS plays a role in several biological activities, including antidiabetic and anticancer activities. However, the effects of a MS ethanolic extract (MSE) on the anti-inflammatory cellular mechanism remain unclear. Here, we investigated the anti-inflammatory properties of MSE and its molecular mechanism both in vitro and in vivo. The effects of MSE on the production of inflammatory mediators, cytokines, and related proteins and the identification of target genes were determined using LPS-stimulated macrophages. We also determined the analgesic and anti-inflammatory effects of MSE by examining acetic acid-induced writhing responses and xylene-induced ear edema in mice. Our results indicated that MSE markedly decreased iNOS and COX-2 levels without causing cytotoxicity and suppressed the secretion of NO in LPS-stimulated macrophages. MSE also inhibited the production of proinflammatory cytokines, such as TNF-[Formula: see text], IL-6, and IL-1[Formula: see text], and induced the expression of HO-1. Moreover, MSE treatment significantly reduced the LPS-stimulated activation of MAPK, NF-[Formula: see text]B, and AP-1. Furthermore, MSE exerted an analgesic effect on the acetic acid-induced abdominal writhing response test and an anti-inflammatory effect on xylene-induced ear edema in ICR mice. Finally, we investigated the components of MSE using UPLC-ESI-MS and found that it contains the maysin as a marker component. Overall, these observations demonstrate that MSE has anti-inflammatory and antinociceptive effects both in vitro and in vivo, which may provide new scientific evidence for its use as a potential therapeutic agent for the treatment of inflammation.
MODELING THE DIRECT AND INDIRECT EFFECTS OF POLLUTANTS ON THE SURVIVAL OF FISH IN WATER BODIES
Authors: TIWARI PANKAJ KUMAR , BULAI IULIA MARTINA , MISRA ARVIND KUMAR , VENTURINO EZIO
Published: September 2017

Several sources of water pollution are causing negative consequences to marine life. The organisms that are more affected are fishes and marine mammals since they are at the top of the food chain. They are directly exposed to high levels of toxins in water and/or they feed on other fishes that are contaminated. Unfortunately, the main cause of the contaminations, and thus of the fish deaths, come from human activities, such as industry, agriculture, municipal wastewater and solid wastes. The present study is concerned with the effect of organic and inorganic pollutants on the survival of fish in water bodies. We introduce a nonlinear mathematical model by considering five interacting variables; organic pollutants, inorganic pollutants, bacteria, dissolved oxygen and fish in the water body. The model is analyzed using the stability theory of differential equations and to confirm the analytical findings, numerical simulations are performed. Our results suggest that to maintain water quality and to save fish life, the global community has to limit the release of organic and inorganic pollutants into the aquatic system.
The Equilibrium Cell-Based Smooth Finite Element Method for Shakedown Analysis of Structures
Authors: Ho P. L. H. , Le C. V. , Chu T. Q.
Published: September 2017

This paper presents a novel equilibrium formulation, that uses the cell-based smoothed method and conic programming, for limit and shakedown analysis of structures. The virtual strains are computed using straining cell-based smoothing technique based on elements of discretized mesh. Fictitious elastic stresses are also determined within the framework of finite element method (CS-FEM)-based Galerkin procedure, and equilibrium equations for residual stresses are satisfied in an average sense at every cell-based smoothing cell. All constrains are imposed at only one point in the smoothing domains, instead of Gauss points as in a standard FEM-based procedure. The resulting optimization problem is then handled using the highly efficient solvers. Various numerical examples are investigated, and obtained solutions are compared with available results in the literature.
How to Integrate Suppliers into the Innovation Process? An Explorative Case of Champion Formalization in the Purchasing Department in Times of Open Innovation
Authors: Maier Maximilian A. , Rück Peter , Brem Alexander
Published: September 2017

Literature on the champion theory proposes the informal character of the champion’s role and also notes difficulties in institutionalizing it. Nevertheless, formally institutionalized roles that seem to fit the description of a champion can be recognized in organizations, especially as enablers of open innovation activities. However, research cannot answer how this institutionalization occurs and which factors influence it. To answer these questions, we investigate a unique single case in which a champion role was institutionalized in the purchasing department of a multinational company. The new role’s task is to identify, select, and integrate supplier innovations. Our results indicate that the informal role of the champion can be successfully institutionalized when certain success factors are considered, which are management commitment, use of success stories, and matching of champions with research and development teams. We contribute to innovation management literature by using the well-established champion theory to explain how and why large multinational companies formally establish the role of the innovation champion. Our research offers pathways for further research about both, the antecedents and the consequences of role formalization. Practitioners can build on the success factors derived in this study when formally implementing innovation champions as enablers of open innovation activities.
Sizes of spaces of triangulations of 4-manifold and balanced presentations of the trivial group
Authors: Lishak Boris , Nabutovsky Alexander
Published: September 2017

Let [Formula: see text] be any compact four-dimensional PL-manifold with or without boundary (e.g. the four-dimensional sphere or ball). Consider the space [Formula: see text] of all simplicial isomorphism classes of triangulations of [Formula: see text] endowed with the metric defined as follows: the distance between a pair of triangulations is the minimal number of bistellar transformations required to transform one of the triangulations into the other. Our main result is the existence of an absolute constant [Formula: see text] such that for every [Formula: see text] and all sufficiently large [Formula: see text] there exist more than [Formula: see text] triangulations of [Formula: see text] with at most [Formula: see text] simplices such that pairwise distances between them are greater than [Formula: see text] ([Formula: see text] times).

This result follows from a similar result for the space of all balanced presentations of the trivial group. (“Balanced” means that the number of generators equals to the number of relations). This space is endowed with the metric defined as the minimal number of Tietze transformations between finite presentations. We prove a similar exponential lower bound for the number of balanced presentations of length [Formula: see text] with four generators that are pairwise [Formula: see text]-far from each other. If one does not fix the number of generators, then we establish a super-exponential lower bound [Formula: see text] for the number of balanced presentations of length [Formula: see text] that are [Formula: see text]-far from each other.
Cervical vertebrae of an enigmatic pterosaur from the Crato Formation (Lower Cretaceous, Araripe Basin, NE Brazil)
Authors: Leal Maria E. C. , Pêgas Rodrigo V. , Bonde Niels , Kellner Alexander W. A.
Published: September 2017

The Brazilian Crato Formation (Lower Cretaceous, Aptian) is well known for its rich pterosaur fauna. This paper deals with a new find represented by four articulated mid-cervical vertebrae. The vertebrae show a morphology consistent with that seen in the Chaoyangopteridae, especially the relative elongation, low neural spines, lack of pneumatic foramina on the lateral face of the centra and the presence of well-developed postexapophyses. Chaoyangopterids are, so far, represented with confidence only in Chinese deposits; the only record outside the Jehol Group is the Crato Formation form
Lacusovagus magnificens
, a partial skull whose assignment to the Chaoyangopteridae has been disputed. Given this controversy, we review the phylogenetic position of
Lacusovagus
, and discuss the nesting of our new specimen among theChaoyangopteridae, providing some comments concerning the composition of the group. We conclude that our new specimen provides further support for the presence of chaoyangopterids in the Early Cretaceous of Brazil.
Tracking Human Motions in Photographing
Authors: Yin Yafeng , Xie Lei , Fan Yuanyuan , Lu Sanglu
Published: September 2017

Due to the portability of smart phones, more and more people tend to take photos with smart phones. However, energy-saving continues to be a thorny problem, since photographing is a rather power hungry function. To extend the battery life of phones while taking photos, we propose a context-aware energy-saving scheme called “SenSave.” SenSave senses the user’s activities during photographing and adopts suitable energy-saving strategies accordingly. SenSave works based on the observation that a lot of energy during photographing is wasted in preparations before shooting. By leveraging the low power-consuming embedded sensors, such as accelerometer and gyroscope, we can recognize the user’s activities and reduce unnecessary energy consumption. Besides, by maintaining an activity state machine, SenSave can determine the user’s activity progressively and improve the recognition accuracy. Experiment results show that SenSave can recognize the user’s activities with an average accuracy of 95.5% and reduce the energy consumption during photographing by 30.0%, when compared to the approach by frequently turning ON/OFF the camera or screen. Additionally, we enhance “SenSave” by introducing an extended Markov chain to predict the next activity state and adopt the energy-saving strategy in advance. Then, we can reduce the energy consumption during photographing by 36.1%.
Metaphors we compute by
Authors: Videla Alvaro
Published: September 2017

Code is a story that explains how to solve a particular problem.
Adaptive Power Management in Solar Energy Harvesting Sensor Node Using Reinforcement Learning
Authors: Shresthamali Shaswot , Kondo Masaaki , Nakamura Hiroshi
Published: September 2017

In this paper, we present an adaptive power manager for solar energy harvesting sensor nodes. We use a simplified model consisting of a solar panel, an ideal battery and a general sensor node with variable duty cycle. Our power manager uses Reinforcement Learning (RL), specifically SARSA(λ) learning, to train itself from historical data. Once trained, we show that our power manager is capable of adapting to changes in weather, climate, device parameters and battery degradation while ensuring near-optimal performance without depleting or overcharging its battery. Our approach uses a simple but novel general reward function and leverages the use of weather forecast data to enhance performance. We show that our method achieves near perfect energy neutral operation (ENO) with less than 6% root mean square deviation from ENO as compared to more than 23% deviation that occur when using other approaches.
Tightening Contention Delays While Scheduling Parallel Applications on Multi-core Architectures
Authors: Rouxel Benjamin , Derrien Steven , Puaut Isabelle
Published: September 2017

Multi-core systems are increasingly interesting candidates for executing parallel real-time applications, in avionic, space or automotive industries, as they provide both computing capabilities and power efficiency. However, ensuring that timing constraints are met on such platforms is challenging, because some hardware resources are shared between cores.

Assuming worst-case contentions when analyzing the schedulability of applications may result in systems mistakenly declared unschedulable, although the worst-case level of contentions can never occur in practice. In this paper, we present two
contention-aware
scheduling strategies that produce a time-triggered schedule of the application’s tasks. Based on knowledge of the application’s structure, our scheduling strategies precisely estimate the
effective
contentions, in order to minimize the overall makespan of the schedule. An Integer Linear Programming (ILP) solution of the scheduling problem is presented, as well as a heuristic solution that generates schedules very close to ones of the ILP (5% longer on average), with a much lower time complexity. Our heuristic improves by 19% the overall makespan of the resulting schedules compared to a worst-case contention baseline.
HiCH
Authors: Azimi Iman , Anzanpour Arman , Rahmani Amir M. , Pahikkala Tapio , Levorato Marco , Liljeberg Pasi , Dutt Nikil
Published: September 2017

The Internet of Things (IoT) paradigm holds significant promises for remote health monitoring systems. Due to their life- or mission-critical nature, these systems need to provide a high level of availability and accuracy. On the one hand, centralized cloud-based IoT systems lack reliability, punctuality and availability (e.g., in case of slow or unreliable Internet connection), and on the other hand, fully outsourcing data analytics to the edge of the network can result in diminished level of accuracy and adaptability due to the limited computational capacity in edge nodes. In this paper, we tackle these issues by proposing a hierarchical computing architecture, HiCH, for IoT-based health monitoring systems. The core components of the proposed system are 1) a novel computing architecture suitable for hierarchical partitioning and execution of machine learning based data analytics, 2) a closed-loop management technique capable of autonomous system adjustments with respect to patient’s condition. HiCH benefits from the features offered by both fog and cloud computing and introduces a tailored management methodology for healthcare IoT systems. We demonstrate the efficacy of HiCH via a comprehensive performance assessment and evaluation on a continuous remote health monitoring case study focusing on arrhythmia detection for patients suffering from CardioVascular Diseases (CVDs).
A Fast Method to Compute Disjunctive Quadratic Invariants of Numerical Programs
Authors: Allamigeon Xavier , Gaubert Stéphane , Goubault Eric , Putot Sylvie , Stott Nikolas
Published: September 2017

We introduce a new method to compute non-convex invariants of numerical programs, which includes the class of switched affine systems with affine guards. We obtain disjunctive and non-convex invariants by associating different partial execution traces with different ellipsoids. A key ingredient is the solution of non-monotone fixed points problems over the space of ellipsoids with a reduction to small size linear matrix inequalities. This allows us to analyze instances that are inaccessible in terms of expressivity or scale by earlier methods based on semi-definite programming.
Demystifying Soft-Error Mitigation by Control-Flow Checking -- A New Perspective on its Effectiveness
Authors: Schuster Simon , Ulbrich Peter , Stilkerich Isabella , Dietrich Christian , SchröDer-Preikschat Wolfgang
Published: September 2017

Soft errors are a challenging and urging problem in the domain of safety-critical embedded systems. For decades, checking schemes have been investigated and improved to mitigate soft-error effects for the class of control-flow faults, with current industrial standards strongly recommending their use.

However, reality looks different: Taking a systems perspective, we implemented four representative Control-Flow Checking (CFC) schemes and put them through their paces in 396 fault-injection campaigns. In contrast to previous work, which typically relied on probability-based vulnerability metrics, we accounted for the influence of memory and time overheads on the fault-space dimensions and applied those in full-scan fault injections. This change in procedure alone severely degraded the perceived effectiveness of CFC.

In addition, we expanded the perspective to data-flow faults and their influence on the overall susceptibility, an aspect that so far has been largely ignored. Our results suggest that, without accompanying measures, any improvement regarding control-flow faults is dominated by the increase in data faults caused by the increased attack surface in terms of memory and runtime overhead. Moreover, CFC performance less depended on the detection capabilities than on general aspects of the concrete binary compilation and execution.

In conclusion, incorporating CFC is not as straightforward as often assumed and the vulnerability of systems with hardened control-flow may in many cases even be increased by the schemes themselves.
An Abstraction-Refinement Theory for the Analysis and Design of Real-Time Systems
Authors: Kurtin Philip S. , Bekooij Marco J. G.
Published: September 2017

Component-based and model-based reasonings are key concepts to address the increasing complexity of real-time systems. Bounding abstraction theories allow to create efficiently analyzable models that can be used to give temporal or functional guarantees on non-deterministic and non-monotone implementations. Likewise, bounding refinement theories allow to create implementations that adhere to temporal or functional properties of specification models. For systems in which jitter plays a major role, both best-case and worst-case bounding models are needed.

In this paper we present a bounding abstraction-refinement theory for real-time systems. Compared to the state-of-the-art TETB refinement theory, our theory is less restrictive with respect to the automatic lifting of properties from component to graph level and does not only support temporal worst-case refinement, but evenhandedly temporal and functional, best-case and worst-case abstraction and refinement.
Optimization of Real-Time Software Implementing Multi-Rate Synchronous Finite State Machines
Authors: Zhao Yecheng , Peng Chao , Zeng Haibo , Gu Zonghua
Published: September 2017

Model-based design using Synchronous Reactive (SR) models is becoming widespread for control software development in industry. However, software synthesis is challenging for multi-rate SR models consisting of blocks modeled with finite state machines, due to the complexity of validating the system’s real-time schedulability. The existing approach uses the simplified periodic task model to allow an efficient schedulability analysis, which leads to pessimistic and suboptimal solutions. Instead, in this paper, we adopt a more accurate but more complex schedulability analysis. We develop several optimization techniques to improve the algorithm’s efficiency. Experimental results on synthetic systems and an industrial case study show that the proposed optimization framework preserves the solution optimality but is much faster (e.g., 1000× for systems with 15 blocks) than the branch-and-bound algorithm, and it generates better control software than the existing approach.
Timing Analysis of Synchronous Programs using WCRT Algebra
Authors: Wang Jiajie , Mendler Michael , Roop Partha , Bodin Bruno
Published: September 2017

Synchronous languages are ideal for designing safety-critical systems. Static Worst-Case Reaction Time (WCRT) analysis is an essential component in the design flow that ensures the real-time requirements are met. There are a few approaches for WCRT analysis, and the most versatile of all is explicit path enumeration. However, as synchronous programs are highly concurrent, techniques based on this approach, such as model checking, suffer from state explosion as the number of threads increases. One observation on this problem is that these existing techniques analyse the program by enumerating a functionally equivalent automaton while WCRT is a non-functional property. This mismatch potentially causes algorithm-induced state explosion. In this paper, we propose a WCRT analysis technique based on the notion of timing equivalence, expressed using WCRT algebra. WCRT algebra can effectively capture the timing behaviour of a synchronous program by converting its intermediate representation Timed Concurrent Control Flow Graph (TCCFG) into a Tick Cost Automaton (TCA), a minimal automaton that is timing equivalent to the original program. Then the WCRT is computed over the TCA. We have implemented our approach and benchmarked it against state-of-the-art WCRT analysis techniques. The results show that the WCRT algebra is 3.5 times faster on average than the fastest published technique.
A Study of Dynamic Phase Adaptation Using a Dynamic Multicore Processor
Authors: Micolet Paul-Jules , Smith Aaron , Dubach Christophe
Published: September 2017

Heterogeneous processors such as ARM’s big.LITTLE have become popular for embedded systems. They offer a choice between running workloads on a high performance core or a low-energy core leading to increased energy efficiency. However, the core configurations are fixed at design time which offers a limited amount of adaptation.

Dynamic Multicore Processors (DMPs) bridge the gap between homogeneous and fully reconfigurable systems. Cores can fuse dynamically to adapt the computational resources to the needs of different workloads. There exists multiple examples of DMPs in the literature, yet the focus has mainly been on static partitioning.

This paper conducts the first thorough study of the potential for dynamic reconfiguration of DMPs at runtime. We study how performance varies with static partitioning and what software optimizations are required to achieve high performance. We show that energy consumption is reduced considerably when adapting the number of cores to program phases, and introduce a simple online model which predicts the optimal number of cores to use to minimize energy consumption while maintaining high performance. Using the San Diego Vision Benchmark Suite as a use case, the dynamic scheme leads to ∼40% energy savings on average without decreasing performance.
An Efficient WCET-Aware Instruction Scheduling and Register Allocation Approach for Clustered VLIW Processors
Authors: Su Xuesong , Wu Hui , Xue Jingling
Published: September 2017

In real-time embedded system design, one major goal is to construct a feasible schedule. Whether a feasible schedule exists depends on the Worst-Case Execution Time (WCET) of each task. Consequently, it is important to minimize the WCET of each task. We investigate the problem of instruction scheduling and register allocation for a program executed on a clustered Very Long Instruction Word (VLIW) processor such that the WCET of the program is minimized, and propose a novel, unified instruction scheduling and register allocation heuristic approach. Our heuristic approach is underpinned by a set of novel techniques, including spanning graph-based WCET-aware live range splitting, WCET-aware dynamic register pressure control, WCET-aware basic block prioritization for performing integrated instruction scheduling and register allocation, and WCET-aware spill code handling. We have implemented our approach in Trimaran 4.0, and compared it with the state-of-the-art approach by using a set of 20 benchmarks. The experimental results show that our approach achieves the maximum WCET improvement of 29.61% and the average WCET improvement of 10.23%, respectively.
The CURE
Authors: Naresh Vignyan Reddy Kothinti , Gope Dibakar , Lipasti Mikko H.
Published: September 2017

VLIW processors typically deliver high performance on limited budget making them ideal for a variety of communication and signal processing solutions. These processors typically need large multi-ported register files that can have side effects of increased cycle time and high power consumption. The access delay and energy of these register files can also become prohibitive when increasing the register count or the access ports, thus limiting the overall performance of the processor. Most prior art circumvent this problem by using multiple clusters with private register files, to lower the access delay and reduce energy consumption. However, clustering artifacts, like increased inter--cluster communication operations and spill-recovery code, result in a performance penalty.

This paper proposes CURE — a novel technique to considerably reduce the negative effects of clustering. CURE augments the ISA to expose the communication registers to the compilers to increase availability of architectural register state to all functional units. The inter--cluster communication operations are integrated into regular ALU and memory operations to improve instruction encoding efficiency. We also propose a new code scheduling heuristic to handle the ISA changes, and to realize the improvements in processor’s performance and energy consumption. Our quantitative analysis estimates that CURE, when compared to the baseline 8--issue uni--cluster processor, boosts average performance by 61% while reducing the average register dynamic energy by 77%.
Complete and Practical Universal Instruction Selection
Authors: Blindell Gabriel Hjort , Carlsson Mats , Lozano Roberto Castañeda , Schulte Christian
Published: September 2017

In code generation, instruction selection chooses processor instructions to implement a program under compilation where code quality crucially depends on the choice of instructions. Using methods from combinatorial optimization, this paper proposes an expressive model that integrates global instruction selection with global code motion. The model introduces (1) handling of memory computations and function calls, (2) a method for inserting additional jump instructions where necessary, (3) a dependency-based technique to ensure correct combinations of instructions, (4) value reuse to improve code quality, and (5) an objective function that reduces compilation time and increases scalability by exploiting bounding techniques. The approach is demonstrated to be complete and practical, competitive with LLVM, and potentially optimal (w.r.t. the model) for medium-sized functions. The results show that combinatorial optimization for instruction selection is well-suited to exploit the potential of modern processors in embedded systems.
DyPO
Authors: Gupta Ujjwal , Patil Chetan Arvind , Bhat Ganapati , Mishra Prabhat , Ogras Umit Y.
Published: September 2017

Modern multiprocessor systems-on-chip (MpSoCs) offer tremendous power and performance optimization opportunities by tuning thousands of potential voltage, frequency and core configurations. As the workload phases change at runtime, different configurations may become optimal with respect to power, performance or other metrics. Identifying the optimal configuration at runtime is infeasible due to the large number of workloads and configurations. This paper proposes a novel methodology that can find the Pareto-optimal configurations at runtime as a function of the workload. To achieve this, we perform an extensive offline characterization to find classifiers that map performance counters to optimal configurations. Then, we use these classifiers and performance counters at runtime to choose Pareto-optimal configurations. We evaluate the proposed methodology by maximizing the performance per watt for 18 single- and multi-threaded applications. Our experiments demonstrate an average increase of 93%, 81% and 6% in performance per watt compared to the interactive, ondemand and powersave governors, respectively.
q
LUT
Authors: Raha Arnab , Raghunathan Vijay
Published: September 2017

Approximate computing has emerged as a popular design paradigm for optimizing the performance and energy consumption of error-resilient applications in domains such as machine learning, graphics, data analytics,
etc
. Numerous techniques for approximate computing have been proposed at different layers of the system stack, from circuits to architecture to software. In this work, we propose a new technique, called
quantized table lookup
, for approximating the meta-functions used in the core computational kernels of error-resilient applications. In contrast to prior work that directly approximates the functionality of the meta-functions, the proposed technique instead approximates the input data to the meta-functions by reducing/quantizing them to
a much smaller set of values that we call quantized inputs
. The small number of quantized inputs enables us to completely replace the energy-intensive arithmetic units in the meta-function with small and energy-efficient lookup tables (called quantized lookup tables or
q
LUT) that contain precomputed output values corresponding to the quantized inputs. The proposed approximation technique is not only highly generic, but also inherently quality-configurable and input-aware. Quality-configurability and input-awareness are achieved by modulating the size of the
q
LUT as well as selecting the values of the quantized inputs judiciously based on the statistics of the original input data. To evaluate the proposed technique, we have implemented the dominant meta-functions of nine error-resilient application benchmarks as quantized table lookup based hardware accelerators using 45nm technology. Experimental results demonstrate average energy savings of 46% at the application-level for minimal (<1%) loss in output quality.
Implementation of Partitioned Mixed-Criticality Scheduling on a Multi-Core Platform
Authors: Trüb Roman , Giannopoulou Georgia , Tretter Andreas , Thiele Lothar
Published: September 2017

Recent industrial trends favor the adoption of multi-core architectures for mixed-criticality applications. Although several mixed-criticality multi-core scheduling approaches have been proposed, currently there are few implementations on hardware that demonstrate efficient resource utilization and the ability to bound interference on shared resources. To address this necessity, we develop a mixed-criticality runtime environment on the Kalray MPPA-256 Andey many-core platform. The runtime environment implements a scheduling policy based on adaptive temporal partitioning. We develop models, methods and implementation principles to implement the necessary scheduling primitives, to achieve high platform utilization and to perform a compositional worst-case execution time analysis. The bounds account for scheduling overheads and for the inter-task interference on the platform’s shared memory. Using realistic benchmarks from avionics and signal processing, we validate the correctness and tightness of the bounds and demonstrate a high platform utilization.
Minimising Access Conflicts on Shared Multi-Bank Memory
Authors: Tretter Andreas , Giannopoulou Georgia , Baer Matthias , Thiele Lothar
Published: September 2017

A common multi-core pattern consists of processors communicating through shared, multi-banked on-chip memory. Two approaches exist: Interleaved address mapping, which spreads consecutive data over all banks, and contiguous address mapping, which stores consecutive data on a single bank.

In this work, we compare both approaches on the Kalray MPPA-256 platform. For contiguous mapping, we propose an algorithm, based on graph colouring techniques, to automatically perform the assignment of data blocks to memory banks with the goal of minimising access collisions and delays. Experiments with representative, parallel real-world benchmarks show that 69% of the tested configurations, when optimised for contiguous mapping by our algorithm, run up to 86% faster on average than with interleaved mapping.
Synthesis of Error-Recovery Protocols for Micro-Electrode-Dot-Array Digital Microfluidic Biochips
Authors: Elfar Mahmoud , Zhong Zhanwei , Li Zipeng , Chakrabarty Krishnendu , Pajic Miroslav
Published: September 2017

A digital microfluidic biochip (DMFB) is an attractive technology platform for various biomedical applications. However, a conventional DMFB is limited by: (i) the number of electrical connections that can be practically realized, (ii) constraints on droplet size and volume, and (iii) the need for special fabrication processes and the associated reliability/yield concerns. To overcome the above challenges, DMFBs based on a micro-electrode-dot-array (MEDA) architecture have been proposed and fabricated recently. Error recovery is of key interest for MEDA biochips due to the need for system reliability. Errors are likely to occur during droplet manipulation due to defects, chip degradation, and the uncertainty inherent in biochemical experiments. In this paper, we first formalize error-recovery objectives, and then synthesize optimal error-recovery protocols using a model based on Stochastic Multiplayer Games (SMGs). We also present a global error-recovery technique that can update the schedule of fluidic operations in an adaptive manner. Using three representative real-life bioassays, we show that the proposed approach can effectively reduce the bioassay completion time and increase the probability of success for error recovery.