bluuebunny/crossref_metadata_2025 huggingface dataset:
Increases in physical activity is as important as smoking cessation for reduction in total mortality in elderly men: 12 years of follow-up of the Oslo II study
Authors: Holme I , Anderssen S A
Published: May 2015

Background

Physical activity (PA) at leisure by the elderly, and its relationship to cardiovascular (CV) and non-CV mortality, with and without competing risk, has been scarcely described. We determined the relationships between PA, smoking and 12-year CV, non-CV and all-cause mortality in elderly Oslo men screened for CV disease in 1972–1973 and 2000.

Methods

Among 14 846 men born during 1923–1932 and participating in 1972–1973, there were 5738 participants in 2000. During the 12 years follow-up 2154 died. Cox regression modelling of mortality endpoints, with and without competing risk, was applied analysing PA variables hours per week of light or vigorous PA intensity and degree of PA at leisure. Comparisons of predictive ability between PA and smoking were done by receiver operating characteristics.

Results

Thirty minutes of PA per 6 days a week was associated with about 40% mortality risk reduction. There was a 5 years increased lifetime when comparing sedentary and moderate to vigorous physically active men. Associations to CV or non-CV mortality were slightly weakened, allowing competing risk. Conditional on the prevalence of smoking and PA, the degree of PA at leisure was almost as predictive as smoking with regard to the effects on mortality. Increase in PA was as beneficial as smoking cessation in reducing mortality.

Conclusions

Even at the age of 73 years, PA is associated highly with mortality between groups of sedentary and active persons. Allowing for competing risk did not weaken these associations markedly. Public health strategies in elderly men should include efforts to increase PA in line with efforts to reduce smoking behaviour.
The influence of friends and siblings on the physical activity and screen viewing behaviours of children aged 5–6 years: a qualitative analysis of parent interviews
Authors: Edwards M J , Jago R , Sebire S J , Kesten J M , Pool L , Thompson J L
Published: May 2015

Objectives

The present study uses qualitative data to explore parental perceptions of how their young child's screen viewing and physical activity behaviours are influenced by their child's friends and siblings.

Design

Telephone interviews were conducted with parents of year 1 children (age 5–6 years). Interviews considered parental views on a variety of issues related to their child's screen viewing and physical activity behaviours, including the influence that their child's friends and siblings have over such behaviours. Interviews were transcribed verbatim and analysed using deductive content analysis. Data were organised using a categorisation matrix developed by the research team. Coding and theme generation was iterative and refined throughout. Data were entered into and coded within N-Vivo.

Setting

Parents were recruited through 57 primary schools located in Bristol and the surrounding area that took part in the B-ProAct1v study.

Participants

Fifty-three parents of children aged 5–6 years.

Results

Parents believe that their child's screen viewing and physical activity behaviours are influenced by their child's siblings and friends. Friends are considered to have a greater influence over the structured physical activities a child asks to participate in, whereas the influence of siblings is more strongly perceived over informal and spontaneous physical activities. In terms of screen viewing, parents suggest that their child's friends can heavily influence the content their child wishes to consume, however, siblings have a more direct and tangible influence over what a child watches.

Conclusions

Friends and siblings influence young children's physical activity and screen viewing behaviours. Child-focused physical activity and screen viewing interventions should consider the important influence that siblings and friends have over these behaviours.
The prevalence, impact and cost of chronic non-cancer pain in Irish primary schoolchildren (PRIME-C): protocol for a longitudinal school-based survey
Authors: O'Higgins Siobhán , Doherty Edel , NicGabhainn Saoirse , Murphy Andrew , Hogan Michael , O'Neill Ciaran , McGuire Brian E
Published: May 2015

Introduction

Previous research has indicated that pain influences children's daily lives, resulting in absence from school, sleep problems, poor school performance and problems with social activities. Our study aims to characterise the nature, extent, impact and cost of chronic pain among Irish children.

Methods and analysis

Using cluster-systematic random sampling, primary schools will be invited to participate and 6000 5–12-year-olds asked to complete questionnaires in school classrooms, at time points 1 year apart. Questionnaires will use internationally valid psychometric measures to assess a range of quality of life factors and chronic pain indicators among children, with corresponding parental/primary caregiver questions, which will be completed at home. Data will also be gathered on the cost of chronic pain. Space will be given for comments on how pain impacts on participants’ lives and possible coping mechanisms.

Ethics and dissemination

Ethical approval has been granted by the Research Ethics Committee, National University of Ireland, Galway. Dissemination of results will be via journal articles and conference presentations on the various aspects of the study (ie, prevalence, impact and economic cost of chronic pain among 5–12-year-olds living in Ireland).
Pseudo-understanding: an analysis of the dilution of value in healthcare
Authors: Fredriksson Jens Jacob , Ebbevi David , Savage Carl
Published: May 2015

Background

Management concepts cycle through healthcare in trends lasting 3–5 years. This may hinder policy-makers, healthcare managers, researchers and clinicians from grasping the intricacies of a management concept and prevent organisations from realising the potential of these concepts. We, therefore, sought to characterise how the newest management concept, value-based healthcare (VBHC), is used and understood in the scientific literature.

Methods

We developed a novel five-step approach: (1) identification of a trend-starting article, (2) identification of key conceptual aspects in the trend-starting article, (3) collection of citing articles and identification of citing text, (4) categorisation of citing text to evaluate which aspects were used and (5) categorisation of citing text according to the structure of observed learning outcomes (SOLO) taxonomy to evaluate understanding.

Results

We identified four aspects in the trend-starting article, ‘What is value in healthcare’, of which value and outcomes were the most cited. More than one-quarter of the citing texts demonstrated no understanding of the aspect referred to; most demonstrated a superficial understanding. Level of understanding was inversely related to journal impact factor (IF), and did not change significantly over time. A deeper understanding was demonstrated in those articles that repeatedly cited the trend-starting article.

Conclusions

None of the four aspects were understood at a level required to develop the management concept of VBHC. VBHC may be undergoing a process of dilution rather than diffusion. To break the cycle of management trends, we encourage a deeper reflective process about the translation of management concepts in healthcare.
British Thoracic Society community acquired pneumonia guideline and the NICE pneumonia guideline: how they fit together
Authors: Lim W S , Smith D L , Wise M P , Welham S A
Published: May 2015

The British Thoracic Society (BTS) guideline for the management of adults with community acquired pneumonia (CAP) published in 2009 was compared with the 2014 National Institute for Health and Care Excellence (NICE) Pneumonia Guideline. Of the 36 BTS recommendations that overlapped with NICE recommendations, no major differences were found in 31, including those covering key aspects of CAP management: timeliness of diagnosis and treatment, severity assessment and empirical antibiotic choice. Of the five BTS recommendations where major differences with NICE were identified, one related to antibiotic duration in low and moderate severity CAP, two to the timing of review of patients and two to legionella urinary antigen testing.
Laparoscopy-assisted ERCP (LA-ERCP) following bariatric gastric bypass surgery: initial experience of a single UK centre
Authors: Paranandi Bharat , Joshi Deepak , Mohammadi Borzoueh , Jenkinson Andrew , Adamo Marco , Read Samantha , Johnson Gavin J , Chapman Michael H , Pereira Stephen P , Webster George J
Published: May 2015

Background

Bariatric gastric bypass surgery is being increasingly performed, but endoscopic retrograde cholangiopancreatography (ERCP) in these patients poses a unique challenge because of a lack of per-oral access to the stomach. Small series suggest a higher technical success rate using laparoscopy-assisted ERCP (LA-ERCP) than with an enteroscopic approach via the Roux-en-Y anastomosis. We present initial experience of LA-ERCP in our unit.

Design

Retrospective case series of consecutive patients undergoing LA-ERCP in our unit between September 2011 and July 2014. Data was retrieved from electronic, clinical and endoscopy records.

Results

Seven LA-ERCPs were performed. All seven patients were female, with median age 44 years (range 36–71). Indications included symptomatic bile duct stones (5/7), benign papillary fibrosis (1/7) and retained biliary stent (1/7). 5/7 (71%) patients had had a prior cholecystectomy. To facilitate LA-ERCP, laparoscopic gastrostomy ports were created in all patients. Duodenal access, biliary cannulation and completion of therapeutic aim were achieved in all patients. 6/7 (86%) patients required endoscopic sphincterotomy. The median duration of procedures was 94 min (range 70–135). Median postoperative length of stay was 2 days (range 1–9). One patient developed mild postprocedural acute pancreatitis, and another patient developed a mild port-site infection. Otherwise, no procedure-related complications were seen. All patients remained well on follow-up (median 14 months (range 1–35) from date of ERCP), with no evidence of further biliary symptoms.

Conclusions

Our early experience of LA-ERCP is that it is safe and effective. The technique may require particular consideration, as bariatric surgery is increasingly performed, in a patient group at significant risk of bile duct stones.
Mothering alone: cross-national comparisons of later-life disability and health among women who were single mothers
Authors: Berkman Lisa F , Zheng Yuhui , Glymour M Maria , Avendano Mauricio , Börsch-Supan Axel , Sabbath Erika L
Published: May 2015

Background

Single motherhood is associated with poorer health, but whether this association varies between countries is not known. We examine associations between single motherhood and poor later-life health in the USA, England and 13 European countries.

Methods

Data came from 25 125 women aged 50+ who participated in the US Health and Retirement Study, the English Longitudinal Study of Ageing and Survey of Health, Ageing and Retirement in Europe. We tested whether single motherhood at ages 16–49 was associated with increased risk of limitations with activities of daily living (ADL), instrumental ADL and fair/poor self-rated health in later life.

Results

33% of American mothers had experienced single motherhood before age 50, versus 22% in England, 38% in Scandinavia, 22% in Western Europe and 10% in Southern Europe. Single mothers had higher risk of poorer health and disability in later life than married mothers, but associations varied between countries. For example, risk ratios for ADL limitations were 1.51 (95% CI 1.29 to 1.98) in England, 1.50 (1.10 to 2.05) in Scandinavia and 1.27 (1.17 to 1.40) in the USA, versus 1.09 (0.80 to 1.47) in Western Europe, 1.13 (0.80 to 1.60) in Southern Europe and 0.93 (0.66 to 1.31) in Eastern Europe. Women who were single mothers before age 20, for 8+ years, or resulting from divorce or non-marital childbearing, were at particular risk.

Conclusions

Single motherhood during early-adulthood or mid-adulthood is associated with poorer health in later life. Risks were greatest in England, the USA and Scandinavia. Selection and causation mechanisms might both explain between-country variation.
The H2 blocker famotidine suppresses progression of ossification of the posterior longitudinal ligament in a mouse model
Authors: Maeda Yujiro , Yamamoto Kenichi , Yamakawa Akira , Aini Hailati , Takato Tsuyoshi , Chung Ung-il , Ohba Shinsuke
Published: May 2015

Background

Ossification of the posterior longitudinal ligament (OPLL) of the spine is a common human myelopathy that leads to spinal cord compression. No disease-modifying drug for OPLL has been identified, whereas surgery and conservative management have been established.

Objectives

To evaluate the therapeutic potential of the H2 blocker famotidine for ectopic ossification in the cervical spine in an OPLL mouse model.

Methods

The H2 blocker famotidine was orally administered toEnpp1ttw/ttwmice, a model of OPLL, at either 4 or 15 weeks of age. Radiological and survival rate analyses were performed to assess the effects of famotidine on OPLL-like lesions and mortality inEnpp1ttw/ttwmice.

Results

Oral administration of famotidine suppressed the progression of OPLL-like ectopic ossification and reduced mortality inEnpp1ttw/ttwmice when administration began at 4 weeks of age, early in the development of ossification.

Conclusions

This study points to the use of famotidine as a disease-modifying drug for ectopic ossification of spinal soft tissue, including OPLL.
Association of treponeme species with atypical foot lesions in goats
Authors: Groenevelt M. , Anzuino K. , Langton D. A. , Grogono‐Thomas R.
Published: May 2015

Five UK goat farms with high levels of lameness (prevalence 14–67 per cent) were investigated. On two farms (farms 1 and 2), the animals presented with typical footrot lesions. The remaining three farms (farms 3, 4 and 5) presented with infected lesions on the foot that did not resemble footrot. These lesions were observed to start from the white line or sole but the interdigital space was rarely affected. Swabs were processed by PCR to assess the presence of Dichelobacter nodosus and three specific treponeme groups (group 1: Treponema medium/Treponema vincentii ‐like, group 2: Treponema phagedenis ‐like and group 3: Treponema denticola/Treponema putidum ‐like) that are reported to be associated with bovine digital dermatitis and contagious ovine digital dermatitis. On farms 1 and 2, 85.7 per cent of samples were found to be positive for D nodosus while only 9.5 per cent were positive for treponeme groups 1, 2 and 3. In contrast, 5.3 per cent of samples from farms 3, 4 and 5 were positive for D nodosus, while 34.2, 68.4 and 36.8 per cent of samples from these farms tested positive for treponeme groups 1, 2 and 3, respectively. T medium/T vincentii ‐like, T phagedenis ‐like and T denticola/T putidum ‐like treponemes were detected on foot lesions of lame goats suggesting that they have a role in the aetiology of this lameness, which has not previously been described in dairy goats.
Analytical studies on an extended car following model for mixed traffic flow with slow and fast vehicles
Authors: Li Zhipeng , Xu Xun , Xu Shangzhi , Qian Yeqing , Xu Juan
Published: May 2015

The car-following model is extended to take into account the characteristics of mixed traffic flow containing fast and slow vehicles. We conduct the linear stability analysis to the extended model with finding that the traffic flow can be stabilized with the increase of the percentage of the slow vehicle. It also can be concluded that the stabilization of the traffic flow closely depends on not only the average value of two maximum velocities characterizing two vehicle types, but also the standard deviation of the maximum velocities among all vehicles, when the percentage of the slow vehicles is the same as that of the fast ones. With increase of the average maximum velocity, the traffic flow becomes more and more unstable, while the increase of the standard deviation takes negative effect in stabilizing the traffic system. The direct numerical results are in good agreement with those of theoretical analysis. Moreover, the relation between the flux and the traffic density is investigated to simulate the effects of the percentage of slow vehicles on traffic flux in the whole density regions.
Evolution method and HOMFLY polynomials for virtual knots
Authors: Bishler Ludmila , Morozov Alexei , Morozov Andrey , Morozov Anton
Published: May 2015

Following the suggestion of Alexei Morozov, Andrey Morozov and Anton Morozov, Phys. Lett. B737, 48 (2014), arXiv:1407.6319, to lift the knot polynomials for virtual knots and links from Jones to HOMFLY, we apply the evolution method to calculate them for an infinite series of twist-like virtual knots and antiparallel two-strand links. Within this family one can check topological invariance and understand how differential hierarchy is modified in virtual case. This opens a way towards a definition of colored (not only cabled) knot polynomials, though problems still persist beyond the first symmetric representation.
Microwave absorption by hydrogen plasma in carbon nanotubes films with layered dielectric structure
Authors: Peng Zhihua , Liu Baoxing , Peng Yanfeng , Jia Peng , Zhan Xiaogui , Xie Ningyu
Published: May 2015

A layered structure model is proposed for microwave dielectric properties of nonhomogeneous hydrogen plasma in carbon nanotubes (CNTs) film. Using the transfer matrix method for solving electromagnetic wave propagation equation, the microwave attenuation of the film is calculated in the range of 0–30 GHz under different conditions. It is found theoretically that with the increase of hydrogen plasma nonhomogeneity, the frequency bandwidth of strong microwave absorption by the film increases markedly. The application of a moderate static magnetic field can effectively improve microwave attenuation properties of hydrogen plasma in CNTs. The numerical results are in good agreement with the available experimental data.
Accurate similarity index based on activity and connectivity of node for link prediction
Authors: Li Longjie , Qian Lvjian , Wang Xiaoping , Luo Shishun , Chen Xiaoyun
Published: May 2015

Recent years have witnessed the increasing of available network data; however, much of those data is incomplete. Link prediction, which can find the missing links of a network, plays an important role in the research and analysis of complex networks. Based on the assumption that two unconnected nodes which are highly similar are very likely to have an interaction, most of the existing algorithms solve the link prediction problem by computing nodes' similarities. The fundamental requirement of those algorithms is accurate and effective similarity indices. In this paper, we propose a new similarity index, namely similarity based on activity and connectivity (SAC), which performs link prediction more accurately. To compute the similarity between two nodes, this index employs the average activity of these two nodes in their common neighborhood and the connectivities between them and their common neighbors. The higher the average activity is and the stronger the connectivities are, the more similar the two nodes are. The proposed index not only commendably distinguishes the contributions of paths but also incorporates the influence of endpoints. Therefore, it can achieve a better predicting result. To verify the performance of SAC, we conduct experiments on 10 real-world networks. Experimental results demonstrate that SAC outperforms the compared baselines.
Evaluation of LBP-Based Facial Emotions Recognition Techniques to Make Consistent Decisions
Authors: Nagaraju C. , Sharadamani D. , Maheswari C. , Vishnu Vardhan D.
Published: May 2015

Decision making is one of the smouldering problems in day to day works. Human emotions play crucial role in decision-making systems. While person is in high emotion he cannot make proper decision. Robust local binary pattern (RLBP) operator is more powerful to recognize the emotions and extends the features of local binary pattern (LBP). However, there are some precincts like discriminating bright faces against dark features and vice versa and intra-class variances increase. The RLBP solves this problem by finding minimum of LBP codes and their complements. However, it miss the mark for different local structures a similar feature is obtained, weak contrast local patterns and similar strong contrast local patterns. Hence, the discriminative robust local binary pattern (DRLBP) method is proposed to retain the contrast information of image patterns next to considering both edge and texture information. Nevertheless, LBP family methods are highly sensitive to noise. To trounce these drawbacks this paper extends fuzzy rule-based DRLBP which is more robust to noise, low contrasted, uneven lighting conditions, variations in expressions and rotation variant images.
Mafic magma replenishment, unrest and eruption in a caldera setting: insights from the 2006 eruption of Rabaul (Papua New Guinea)
Authors: Bouvet de Maisonneuve C. , Costa F. , Patia H. , Huber C.
Published: May 2015

Understanding the magmatic processes that drive unrest at silicic calderas remains a major goal in Volcanology. Rabaul in Papua New Guinea is an exceptional location because after two decades of unrest and a peak in seismicity and deformation in 1983–85, eruptive activity began in 1994 and is still ongoing. A particularly large sub-Plinian eruption occurred from Tavurvur in October 2006. Whole-rock compositions are andesitic and reflect mixing/mingling between basaltic and dacitic magmas from the same system. The magmas that fed the 2006 eruption were stored at about 930°C, with 1–3 wt% H
2
O, 25–520 ppm CO
2
, and 50–2500 ppm SO
2
in the melt. Melt inclusions hosted in pyroxene, and plagioclase phenocrysts record fractional crystallization at ≤200 MPa under relatively dry and poorly oxidizing conditions. Magma mixing/mingling is expressed as heterogeneous glass compositions, strongly zoned phenocrysts, and mafic crystal aggregates. A textural maturation from fine, acicular to large, blocky crystal clots implies different relative ages of formation. Modelling the chemical zoning of plagioclase shows that mafic–silicic interactions started a couple of decades prior to the 2006 eruption and continued until days to weeks prior to eruption. Basaltic replenishments have been driving unrest and eruption at the Rabaul caldera since the 1970s.

Supplementary material:

Tables and figures reporting the composition of the Tavurvur 2006, Kombiu and 1.4 ka BP caldera samples and showing thermodynamic modelling with MELTS are available at
http://www.geolsoc.org.uk/SUP18816
Resolving discordant U–Th–Ra ages: constraints on petrogenetic processes of recent effusive eruptions at Tatun Volcano Group, northern Taiwan
Authors: Zellmer Georg F. , Rubin Kenneth H. , Miller Christian A. , Shellnutt J. Gregory , Belousov Alexander , Belousova Marina
Published: May 2015

U–Th–Ra isotope analyses of whole rocks and mineral separates were conducted in order to perform isochron dating of three morphologically young lavas from Tatun volcano, northern Taiwan (from Mt Cising, the Shamao dome and the Huangzuei volcano). The data do not yield tight U–Th isochrons, indicating open-system magmatic processes. However, crystallization ages of two samples can be constrained: namely, less than about 1370 years for the Shamao dome, based on
226
Ra–
230
Th disequilibrium in magnetite, and less than approximately 70 ka (but potentially Holocene) for a Huangzuei flow, based on
238
U–
230
Th disequilibrium in plagioclase. Discordant Ar–Ar,
238
U–
230
Th and
226
Ra–
230
Th ages are best explained by young lavas having inherited some crystals from older lithologies (crystal mushes or rocks), and indicate that the above ages represent maxima. Our study provides the first evidence of effusive volcanism at the Tatun Volcano Group in Late Holocene times. All separates from the Shamao dome and Huangzuei volcano are in
234
U–
238
U equilibrium. Minerals in the Mt Cising sample are in
234
U–
238
U disequilibrium, despite the
234
U–
238
U equilibrium of the whole rock. We interpret this as uptake of a hydrothermally altered, old crystal cargo into fresh melt prior to eruption. A different dating approach will thus be required to constrain the eruption age of Mt Cising.

Supplementary material:

Ar–Ar plateaus from Mt Cising and the Shamao dome, reproduced from Lee (1996), are available at
www.geolsoc.org.uk/SUP18817
Timescales of crustal magma reservoir processes: insights from U-series crystal ages
Authors: Cooper Kari M.
Published: May 2015

The dynamic processes operating within crustal magma reservoirs control many aspects of the chemical composition of erupted magmas, and crystals in volcanic rocks provide a temporally constrained archive of these changing environments. In this review, I compile
238
U–
230
Th ages of accessory phases and
238
U–
230
Th–
226
Ra ages of bulk mineral separates of major phases. These data document that crystals in individual samples can have ages spanning most of the history of a volcanic centre. Age populations for accessory phases show protracted pre-eruptive crystal residence times but few crystals predate magmatic activity at a given centre. These data have been interpreted in the context of residence times of the host magmas or timescales of the storage of crystals within a largely crystalline portion of the reservoir system. In contrast, less than half of the bulk separate
238
U–
230
Th–
226
Ra ages for major phases are more than 10 kyr older than the eruption. Many of these apparently conflicting observations of ages of major and accessory phases can be reconciled within the context of a model where a crystal mush was remobilized during processes leading to eruption. Overall, the compiled data show that crystals contain rich archives of magmatic processes in crustal reservoirs, especially when combined with other crystal-scale geochemical data.

Supplementary material:

Compilation of U–Th–Pb ages of accessory phases and associated references are available at
www.geolsoc.org.uk/SUP18820
Software Change Contracts
Authors: Yi Jooyong , Qi Dawei , Tan Shin Hwei , Roychoudhury Abhik
Published: May 2015

Software errors often originate from incorrect changes, including incorrect program fixes, incorrect feature updates, and so on. Capturing the intended program behavior explicitly via contracts is thus an attractive proposition. In our recent work, we had espoused the notion of “change contracts” to express the intended program behavior changes across program versions. Change contracts differ from program contracts in that they do not require the programmer to describe the intended behavior of those program features which are unchanged across program versions. In this work, we present the formal semantics of our change contract language built on top of the
Java modeling language
(JML). Our change contract language can describe behavioral as well as structural changes. We evaluate the expressivity of the change contract language via a survey given to final-year undergraduate students. The survey results enable to understand the usability of our change contract language for purposes of writing contracts, comprehending written contracts, and modifying programs according to given change contracts.

Finally, we develop both dynamic and static checkers for change contracts, and show how they can be used in maintaining software changes. We use our dynamic checker to automatically suggest tests that manifest violations of change contracts. Meanwhile, we use our static checker to verify that a program is changed as specified in its change contract. Apart from verification, our static checker also performs various other software engineering tasks, such as localizing the buggy method, detecting/debugging regression errors, and classifying the cause for a test failure as either error in production code or error in test code.
A Baseline Model for Software Effort Estimation
Authors: Whigham Peter A. , Owen Caitlin A. , Macdonell Stephen G.
Published: May 2015

Software effort estimation
(SEE) is a core activity in all software processes and development lifecycles. A range of increasingly complex methods has been considered in the past 30 years for the prediction of effort, often with mixed and contradictory results. The comparative assessment of effort prediction methods has therefore become a common approach when considering how best to predict effort over a range of project types. Unfortunately, these assessments use a variety of sampling methods and error measurements, making comparison with other work difficult. This article proposes an
automatically transformed linear model
(ATLM) as a suitable baseline model for comparison against SEE methods. ATLM is simple yet performs well over a range of different project types. In addition, ATLM may be used with mixed numeric and categorical data and requires no parameter tuning. It is also deterministic, meaning that results obtained are amenable to replication. These and other arguments for using ATLM as a baseline model are presented, and a reference implementation described and made available. We suggest that ATLM should be used as a baseline of effort prediction quality for all future model comparisons in SEE.
Trajectory Data Mining
Authors: Zheng Yu
Published: May 2015

The advances in location-acquisition and mobile computing techniques have generated massive spatial trajectory data, which represent the mobility of a diversity of moving objects, such as people, vehicles, and animals. Many techniques have been proposed for processing, managing, and mining trajectory data in the past decade, fostering a broad range of applications. In this article, we conduct a systematic survey on the major research into
trajectory data mining
, providing a panorama of the field as well as the scope of its research topics. Following a road map from the derivation of trajectory data, to trajectory data preprocessing, to trajectory data management, and to a variety of mining tasks (such as trajectory pattern mining, outlier detection, and trajectory classification), the survey explores the connections, correlations, and differences among these existing techniques. This survey also introduces the methods that transform trajectories into other data formats, such as graphs, matrices, and tensors, to which more data mining and machine learning techniques can be applied. Finally, some public trajectory datasets are presented. This survey can help shape the field of
trajectory data mining
, providing a quick understanding of this field to the community.
Deciding Type-Based Partial-Order Constraints for Path-Sensitive Analysis
Authors: Sherman Elena , Garvin Brady J. , Dwyer Matthew B.
Published: May 2015

The precision and scalability of path-sensitive program analyses depend on their ability to distinguish feasible and infeasible program paths. Analyses express path feasibility as the satisfiability of conjoined branch conditions, which is then decided by cooperating decision procedures such as those in
satisfiability modulo theory
(SMT) solvers. Consequently, efficient underlying decision procedures are key to precise, scalable program analyses.

When we investigate the branch conditions accumulated by inter-procedural path-sensitive analyses of object-oriented programs, we find that many relate to an object's dynamic type. These conditions arise from explicit type tests and the branching implicit in dynamic dispatch and type casting. These conditions share a common form that comprises a fragment of the theory of partial orders, which we refer to as
type-based partial orders (TPO)
.

State-of-the-art SMT solvers can heuristically instantiate the quantified formulae that axiomatize partial orders, and thereby support TPO constraints. We present two custom decision procedures with significantly better performance. On benchmarks that reflect inter-procedural path-sensitive analyses applied to significant Java systems, the custom procedures run three orders of magnitude faster. The performance of the two decision procedures varies across benchmarks, which suggests that a portfolio approach may be beneficial for solving constraints generated by program analyses.
SqueakJS
Authors: Freudenberg Bert , Ingalls Dan H.H. , Felgentreff Tim , Pape Tobias , Hirschfeld Robert
Published: May 2015

We report our experience in implementing SqueakJS, a bit-compatible implementation of Squeak/Smalltalk written in pure JavaScript. SqueakJS runs entirely in the Web browser with a virtual filesystem that can be directed to a server or client-side storage. Our implementation is notable for simplicity and performance gained through adaptation to the host object memory and deployment leverage gained through the Lively Web development environment. We present several novel techniques as well as performance measurements for the resulting virtual machine. Much of this experience is potentially relevant to preserving other dynamic language systems and making them available in a browser-based environment.
Projectional editing of variational software
Authors: Walkingshaw Eric , Ostermann Klaus
Published: May 2015

Editing the source code of variational software is complicated by the presence of variation annotations, such as #ifdef statements, and by code that is only included in some configurations. When editing some configurations and not others, it would be easier to edit a simplified version of the source code that includes only the configurations we currently care about. In this paper, we present a projectional editing model for variational software. Using our approach, a programmer can partially configure a variational program, edit this simplified view of the code, and then automatically update the original, fully variational source code. The model is based on an isolation principle where edits affect only the variants that are visible in the view. We show that this principle has several nice properties that are suggested by related work on bidirectional transformations.
Automatic feature selection in large-scale system-software product lines
Authors: Ruprecht Andreas , Heinloth Bernhard , Lohmann Daniel
Published: May 2015

System software can typically be configured at compile time via a comfortable feature-based interface to tailor its functionality towards a specific use case. However, with the growing number of features, this tailoring process becomes increasingly difficult: As a prominent example, the Linux kernel in v3.14 provides nearly 14 000 configuration options to choose from. Even developers of embedded systems refrain from trying to build a minimized distinctive kernel configuration for their device – and thereby waste memory and money for unneeded functionality. In this paper, we present an approach for the automatic use-case specific tailoring of system software for special-purpose embedded systems. We evaluate the effectiveness of our approach on the example of Linux by generating tailored kernels for well-known applications of the Rasperry Pi and a Google Nexus 4 smartphone. Compared to the original configurations, our approach leads to memory savings of 15–70 percent and requires only very little manual intervention.
Efficient testing of software product lines via centralization (short paper)
Authors: Ma Lei , Artho Cyrille , Zhang Cheng , Sato Hiroyuki
Published: May 2015

Software product line~(SPL) engineering manages families of software products that share common features. However, cost-effective test case generation for an SPL is challenging. Applying existing test case generation techniques to each product variant separately may test common code in a redundant way. Moreover, it is difficult to share the test results among multiple product variants. In this paper, we propose the use of centralization, which combines multiple product variants from the same SPL and generates test cases for the entire system. By taking into account all variants, our technique generally avoids generating redundant test cases for common software components. Our case study on three SPLs shows that compared with testing each variant independently, our technique is more efficient and achieves higher test coverage.
LibDSL: a library for developing embedded domain specific languages in d via template metaprogramming
Authors: Shioda Masato , Iwasaki Hideya , Sato Shigeyuki
Published: May 2015

This paper presents a library called LibDSL that helps the implementer of an embedded domain specific language (EDSL) effectively develop it in D language. The LibDSL library accepts as input some kinds of ``specifications'' of the EDSL that the implementer is going to develop and a D program within which an EDSL source program written by the user is embedded. It produces the front-end code of an LALR parser for the EDSL program and back-end code of the execution engine. LibDSL is able to produce two kinds of execution engines, namely compiler-based and interpreter-based engines, either of which the user can properly choose depending on whether an EDSL program is known at compile time or not. We have implemented the LibDSL system by using template metaprogramming and other advanced facilities such as compile-time function execution of D language. EDSL programs developed by means of LibDSL have a nice integrativeness with the host language.
Pin++: an object-oriented framework for writing pintools
Authors: Hill James H. , Feiock Dennis C.
Published: May 2015

This paper presents a framework named Pin++. Pin++ is an object-oriented framework that uses template metaprogramming to implement Pintools, which are analysis tools for the dynamic binary instrumentation tool named Pin. The goal of Pin++ is to simplify programming a Pintool and promote reuse of its components across different Pintools. Our results show that Pintools implemented using Pin++ can have a 54% reduction in complexity, increase its modularity, and up to 60% reduction in instrumentation overhead.
SD-PCM
Authors: Wang Rujia , Jiang Lei , Zhang Youtao , Yang Jun
Published: May 2015

Phase Change Memory (PCM) has better scalability and smaller cell size comparing to DRAM. However, further scaling PCM cell in deep sub-micron regime results in significant thermal based write disturbance (WD). Naively allocating large inter-cell space increases cell size from 4F
2
ideal to 12F
2
. While a recent work mitigates WD along word-lines through disturbance resilient data encoding, it is ineffective for WD along bit-lines, which is more severe due to widely adopted $\mu$Trench structure in constructing PCM cell arrays. Without mitigating WD along bit-lines, a PCM cell still has 8F2, which is 100% larger than the ideal. In this paper, we propose SD-PCM for achieving reliable write operations in super dense PCM. In particular, we focus on mitigating WD along bit-lines such that we can construct super dense PCM chips with 4F
2
cell size, i.e., the minimal for diode-switch based PCM. Based on simple verification-n-correction (VnC), we propose LazyCorrection and PreRead to effectively reduce VnC overhead and minimize cascading verification during write. We further propose (n:m)-Alloc for achieving good tradeoff between VnC overhead minimization and memory capacity loss. Our experimental results show that, comparing to a WD-free low density PCM, SD-PCM achieves 80% capacity improvement in cell arrays while incurring around 0-10% performance degradation when using different (n:m) allocators.
Monitoring and Debugging the Quality of Results in Approximate Programs
Authors: Ringenburg Michael , Sampson Adrian , Ackerman Isaac , Ceze Luis , Grossman Dan
Published: May 2015

Energy efficiency is a key concern in the design of modern computer systems. One promising approach to energy-efficient computation, approximate computing, trades off output accuracy for significant gains in energy efficiency. However, debugging the actual cause of output quality problems in approximate programs is challenging. This paper presents dynamic techniques to debug and monitor the quality of approximate computations. We propose both offline debugging tools that instrument code to determine the key sources of output degradation and online approaches that monitor the quality of deployed applications.

We present two offline debugging techniques and three online monitoring mechanisms. The first offline tool identifies correlations between output quality and the execution of individual approximate operations. The second tracks approximate operations that flow into a particular value. Our online monitoring mechanisms are complementary approaches designed for detecting quality problems in deployed applications, while still maintaining the energy savings from approximation.

We present implementations of our techniques and describe their usage with seven applications. Our online monitors control output quality while still maintaining significant energy efficiency gains, and our offline tools provide new insights into the effects of approximation on output quality.
Beyond the PDP-11
Authors: Chisnall David , Rothwell Colin , Watson Robert N.M. , Woodruff Jonathan , Vadera Munraj , Moore Simon W. , Roe Michael , Davis Brooks , Neumann Peter G.
Published: May 2015

We propose a new memory-safe interpretation of the C abstract machine that provides stronger protection to benefit security and debugging. Despite ambiguities in the specification intended to provide implementation flexibility, contemporary implementations of C have converged on a memory model similar to the PDP-11, the original target for C. This model lacks support for memory safety despite well-documented impacts on security and reliability.

Attempts to change this model are often hampered by assumptions embedded in a large body of existing C code, dating back to the memory model exposed by the original C compiler for the PDP-11. Our experience with attempting to implement a memory-safe variant of C on the CHERI experimental microprocessor led us to identify a number of problematic idioms. We describe these as well as their interaction with existing memory safety schemes and the assumptions that they make beyond the requirements of the C specification. Finally, we refine the CHERI ISA and abstract model for C, by combining elements of the CHERI capability model and fat pointers, and present a softcore CPU that implements a C abstract machine that can run legacy C code with strong memory protection guarantees.
Architectural Support for Software-Defined Metadata Processing
Authors: Dhawan Udit , Hritcu Catalin , Rubin Raphael , Vasilakis Nikos , Chiricescu Silviu , Smith Jonathan M. , Knight Thomas F. , Pierce Benjamin C. , DeHon Andre
Published: May 2015

Optimized hardware for propagating and checking software-programmable metadata tags can achieve low runtime overhead. We generalize prior work on hardware tagging by considering a generic architecture that supports software-defined policies over metadata of arbitrary size and complexity; we introduce several novel microarchitectural optimizations that keep the overhead of this rich processing low. Our model thus achieves the efficiency of previous hardware-based approaches with the flexibility of the software-based ones. We demonstrate this by using it to enforce four diverse safety and security policies---spatial and temporal memory safety, taint tracking, control-flow integrity, and code and data separation---plus a composite policy that enforces all of them simultaneously. Experiments on SPEC CPU2006 benchmarks with a PUMP-enhanced RISC processor show modest impact on runtime (typically under 10%) and power ceiling (less than 10%), in return for some increase in energy usage (typically under 60%) and area for on-chip memory structures (110%).
Architectural Support for Dynamic Linking
Authors: Agrawal Varun , Dabral Abhiroop , Palit Tapti , Shen Yongming , Ferdman Michael
Published: May 2015

All software in use today relies on libraries, including standard libraries (e.g., C, C++) and application-specific libraries (e.g., libxml, libpng). Most libraries are loaded in memory and dynamically linked when programs are launched, resolving symbol addresses across the applications and libraries. Dynamic linking has many benefits: It allows code to be reused between applications, conserves memory (because only one copy of a library is kept in memory for all the applications that share it), and allows libraries to be patched and updated without modifying programs, among numerous other benefits. However, these benefits come at the cost of performance. For every call made to a function in a dynamically linked library, a trampoline is used to read the function address from a lookup table and branch to the function, incurring memory load and branch operations. Static linking avoids this performance penalty, but loses all the benefits of dynamic linking. Given its myriad benefits, dynamic linking is the predominant choice today, despite the performance cost. In this work, we propose a speculative hardware mechanism to optimize dynamic linking by avoiding executing the trampolines for library function calls, providing the benefits of dynamic linking with the performance of static linking. Speculatively skipping the memory load and branch operations of the library call trampolines improves performance by reducing the number of executed instructions and gains additional performance by reducing pressure on the instruction and data caches, TLBs, and branch predictors. Because the indirect targets of library call trampolines do not change during program execution, our speculative mechanism never misspeculates in practice. We evaluate our technique on real hardware with production software and observe up to 4% speedup using only 1.5KB of on-chip storage.
Reduced Hardware NOrec
Authors: Matveev Alexander , Shavit Nir
Published: May 2015

Because of hardware TM limitations, software fallbacks are the only way to make TM algorithms guarantee progress. Nevertheless, all known software fallbacks to date, from simple locks to sophisticated versions of the NOrec Hybrid TM algorithm, have either limited scalability or weakened semantics. We propose a novel reduced-hardware (RH) version of the NOrec HyTM algorithm. Instead of an all-software slow path, in our RH NOrec the slow-path is a "mix" of hardware and software: one short hardware transaction executes a maximal amount of initial reads in the hardware, and the second executes all of the writes. This novel combination of the RH approach and the NOrec algorithm delivers the first Hybrid TM that scales while fully preserving the hardware's original semantics of opacity and privatization.

Our GCC implementation of RH NOrec is promising in that it shows improved performance relative to all prior methods, at the concurrency levels we could test today.
Continuous mucociliary transport by primary human airway epithelial cells in vitro
Authors: Sears Patrick R. , Yin Wei-Ning , Ostrowski Lawrence E.
Published: May 2015

Mucociliary clearance (MCC) is an important innate defense mechanism that continuously removes inhaled pathogens and particulates from the airways. Normal MCC is essential for maintaining a healthy respiratory system, and impaired MCC is a feature of many airway diseases, including both genetic (cystic fibrosis, primary ciliary dyskinesia) and acquired (chronic obstructive pulmonary disease, bronchiectasis) disorders. Research into the fundamental processes controlling MCC, therefore, has direct clinical application, but has been limited in part due to the difficulty of studying this complex multicomponent system in vitro. In this study, we have characterized a novel method that allows human airway epithelial cells to differentiate into a mucociliary epithelium that transports mucus in a continuous circular track. The mucociliary transport device allows the measurement and manipulation of all features of mucociliary transport in a controlled in vitro system. In this initial study, the effect of ciliary beat frequency and mucus concentration on the speed of mucociliary transport was investigated.