bluuebunny/crossref_metadata_2025 huggingface dataset:
OPTIMAL MEAN–VARIANCE PORTFOLIO SELECTION WITH NO-SHORT-SELLING CONSTRAINT
Authors: XU JINGSI
Published: November 2020

In this paper, the objective is to study the continuous mean–variance portfolio selection with a no-short-selling constraint and obtain a time-consistent solution. We assume that there is a self-financing portfolio with wealth process [Formula: see text], in which [Formula: see text] represents the fraction of wealth invested in the risk asset under the short selling prohibition. We investigate the mean–variance optimal constrained problem defined by obtaining the supremum over all admissible controls of the difference between the expectation of the value process at some designated terminal time [Formula: see text] and a positive constant times the variance of [Formula: see text]. To envisage the quadratic nonlinearity introduced by the variance, the method of Lagrangian multipliers reduces the nonlinear problem into a set of linear problems which can be solved by applying the Hamilton–Jacobi–Bellman equation and change of variables formula with local time on curves. Solving the HJB system provides the time-inconsistent solution and from there, we derive the time-consistent optimal control.
Interacting Fock spaces and subproduct systems
Authors: Gerhold Malte , Skeide Michael
Published: November 2020

We present a new more flexible definition of interacting Fock space that allows to resolve in full generality the problem of embeddability. We show that the same is not possible for regularity. We apply embeddability to classify interacting Fock spaces by squeezings. We give necessary and sufficient criteria for when an interacting Fock space has only bounded creators, giving thus rise to new classes of non-selfadjoint and selfadjoint operator algebras.
Types of factors generated by quantum Markov states of Ising model with competing interactions on the Cayley tree
Authors: Mukhamedov Farrukh , Souissi Abdessatar
Published: November 2020

In this paper, we consider Quantum Markov States (QMS) corresponding to the Ising model with competing interactions on the Cayley tree of order two. Earlier, some algebraic properties of these states were investigated. In this paper, we prove that if the competing interaction is rational then the von Neumann algebra, corresponding to the QMS associated with disordered phase of the model, has type [Formula: see text], [Formula: see text].
On the p-Adic analog of Richards’ equation with the finite difference method
Authors: Pourhadi Ehsan , Khrennikov Andrei Yu. , Saadati Reza
Published: November 2020

In this paper, with the help of a variant of Schauder fixed point theorem in the real Banach algebra together with the finite difference method (FDM), we take a brief look at the [Formula: see text]-adic analog of Richards’ equation derived by Khrennikov et al. [Application of [Formula: see text]-adic wavelets to model reaction–diffusion dynamics in random porous media, J. Fourier Anal. Appl. 22 (2016) 809–822], and study the solvability and solution of this problem. This equation is formulated by a kinetic equation during the modeling of the reaction–diffusion dynamics in random porous media. Moreover, in order to guarantee the convergence of the presented iterative schemes, some sufficient conditions would be presented.
Crashworthiness Analysis for Structural Stability and Dynamics
Authors: Sharma Sunil Kumar , Lee Jaesun
Published: November 2020

In this paper, we fabricate human DNA and polar bear inspired thin-walled tube that tends to reduce the strength of decelerating force during impact, while escalating the amount of energy absorbed. The crashworthiness performance under axial impact is investigated using experimental analysis and non-linear finite element analysis (FEA). The investigation is conducted in three phases; the first phase consists of the design and fabrication of a novel bio-inspired tube (BIT) motivated by the most stable human DNA. Twelve BITs are created by filling cylindrical tubes into different positions of the BIT, which was inspired by the microstructural of polar bear hair. The second phase comprises the nonlinear FEA of energy-absorbed ability for different BITs under axial impact loading using LS-DYNA software, and then validated by the Simplified Super Folding Element (SSFE) theorem. In the third phase, Radial Basis Function (RBF) meta-models and Non-dominated Sorting Genetic Algorithm II (NSGA-II) are used for the multi-objective optimization design of BIT-11. The numerical simulation results are compared with the experimental results to confirm the crash behavior and energy absorption (EA) characteristics of the optimal structure over a base one. Based on the results, the suited configuration with required performance in crashworthiness is suggested, which should be incorporated into automobiles for safety consideration of passengers during an impact. The results show an increment of 49% in Specific Energy Absorption (SEA), suggesting the better choice of a particular tube over the base tube.
A Turn-on Fluorescent Sensor Based on Copper-Based Metal-Organic Frameworks for Sensitive Detection of L-Histidine
Authors: Chu Chengxiang , Huang Rui , Wang Xianfeng , Deng Yuanyi , Gu Tao , Huo Danqun , Zhang Liang , Zhong Daidi , Hou Changjun
Published: November 2020

As an important amino acid in the body, L-histidine participates in various physiological processes. Therefore, it is of great necessity to establish a rapid and effective method for L-histidine sensing, especially in blood and urine. In this work, a fluorescence sensor for detection of L-histidine was successfully developed using Cu-MOFs/Fe[Formula: see text] sensor. Cu-MOFs with blue emission served as the identification unit and signal source, and Fe[Formula: see text] played the role of “quencher” in this system. Fe[Formula: see text] induced the fluorescence quenching of Cu-MOFs to form Cu-MOFs/Fe[Formula: see text] sensor due to the effect of photoinduced electron transfer (PET). After the addition of L-histidine, Fe[Formula: see text] was captured by L-histidine to form L-histidine-Fe[Formula: see text] complex, which inhibited the PET effect from Cu-MOFs to Fe[Formula: see text], resulting in the fluorescence recovery of Cu-MOFs. With such a design, L-histidine detection was realized with a wide linear range from 1[Formula: see text][Formula: see text]M to 190[Formula: see text][Formula: see text]M. The limit of detection (LOD) was calculated as low as 0.156[Formula: see text][Formula: see text]M. In addition, successful detection of L-histidine in blood serum with high selectivity and sensitivity indicated the real applications and potential diagnostic value of Cu-MOFs/Fe[Formula: see text] system.
Symmetry-breaking polygons on a rotating fluid surface
Authors: Xianbo Christopher Ong
Published: November 2020

When a circular plate is rotated at the bottom of a cylindrical vessel containing fluid, the fluid surface can form stable polygons under certain conditions. This phenomenon is very surprising, as it seems that the rotational symmetry of the setup is mysteriously broken when polygons are formed. I experimentally measured the geometries of the formed polygons and studied their dependence on parameters such as the plate rotational rate. Both the number of sides and the sizes of the polygons were found to increase when the plate rotated faster.

In my research, I sought to develop a theoretical model that could accurately predict the properties of the formed polygons in agreement with experimental results. Taking on a novel approach of analysing the forces on a fluid particle travelling along the boundary of the polygon, the mechanism of polygon formation and the effect of the plate rotation on the polygons were physically understood. Applying it quantitatively, with considerations on the properties of the fluid flow, a differential equation governing the polygon’s steadystate geometry was formulated. A high degree of predictive power into the shape of the polygon was achieved, closely matching experimental data.

One sentence version: My research develops a theoretical model to predict the properties of symmetrybreaking polygons formed on a rotating fluid surface.
Scaffold Proteins and their Roles in Human Diseases
Authors: Mukherjee Somsubhro , Low Boon Chuan
Published: November 2020

Scaffold proteins are critical regulators of important cell signaling pathways. Though scaffolds are not stringently defined in meaning, they are known to interact with numerous components of a signaling pathway, binding and bridging them into distinct and functional complexes. They control signal transduction and assist the localization of pathway components (organized in complexes) to definite regions of the cell such as the endosomes, plasma membrane, the cytoplasm, mitochondria, Golgi, and the nucleus. Years of research in this field have revealed the versatility of this class of protein and the important role it plays in maintaining the normal functions of the human body. Here, we discuss the role of several scaffold proteins which are implicated in important signaling pathways that play important roles in cardiac diseases, metabolic diseases, neurological disorders, and cancer. Their versatility and functions in human diseases make them attractive drug targets, several of which have been investigated in clinical trials. Future studies of scaffold proteins should give us an in-depth knowledge of how cell signaling works in normal and pathological conditions and would offer avenues to disrupt harmful cellular pathways to circumvent diseases.
WWOX is a Risk Factor for Alzheimer’s Disease: How and Why?
Authors: Sze Chun-I , Wen Kuang-Yu , Chang Nan-Shan
Published: November 2020

A recent large genome-wide association meta-analysis revealed that the human WWOX gene is regarded as one of the five newly identified risk factors for Alzheimer’s disease (AD). However, this study did not functionally characterize how WWOX protein deficiency affects AD initiation, progression and neurodegeneration. In this review, evidence and perspectives are provided regarding how WWOX works in limiting neurodegeneration. Firstly, loss of WWOX/Wwox gene leads to severe neural diseases with degeneration, metabolic disorder and early death in the newborns. Downregulation of pY33-WWOX may start at middle ages, and this leads to slow aggregation of a cascade of proteins, namely TRAPPC6A[Formula: see text], TIAF1 and SH3GLB2, that leads to amyloid-beta (A[Formula: see text]) formation and tau tangle formation in old-aged AD patients. Secondly, functional antagonism between tumor suppressors p53 and WWOX may occur in vivo, in which p53-mediated inflammation is blocked by WWOX. Loss of balance in the functional antagonism leads to aggregation of pathogenic proteins for AD such as tau and A[Formula: see text] in the brain cortex and hippocampus. Thirdly, downregulation of pY33-WWOX is accompanied by upregulation of pS14-WWOX. The event frequently correlates with enhanced AD progression and cancer cell growth in vivo. A small peptide Zfra4-10 dramatically suppresses pS14-WWOX and restores memory loss in triple transgenic (3xTg) mice, and inhibits cancer growth in mice as well. Finally, a supporting scenario is that WWOX deficiency induces enhanced cell migration and loss of cell-to-cell recognition. This allows the generation of neuronal heterotopia and associated epileptic seizure in WWOX-deficient newborn patients.
Carboniferous conodont biostratigraphy
Authors: Barrick James E. , Alekseev Alexander S. , Blanco-Ferrera Silvia , Goreva Natalia V. , Hu Keyi , Lambert Lance L. , Nemyrovska Tamara I. , Qi Yuping , Ritter Scott M. , Sanz-López Javier
Published: November 2020

Carboniferous conodont biostratigraphy comprises regional zonations that reflect the palaeogeographical distribution of taxa and distinct shallow-water and deep-water conodont biofacies. Some species have a global distribution and can effect high quality correlations. These taxa are incorporated into definitions of global Carboniferous chronostratigraphic units. A standard global Carboniferous zonation has not been developed. The lowermost Mississippian is zoned by
Siphonodella
species, excepet in shallow-water facies, where other polygnathids are used.
Gnathodus
species radiated during the Tournaisian and are used to define many Mississippian zones. A late Tournaisian maximum in diversity, characterized by short-lived genera, was followed by lower diversity faunas of
Gnathodus
species and carminate genera through the Visean and Serpukhovian. By the late Visean and Serpukhovian,
Lochriea
provides better biostratigraphic resolution. Shallow-water zonations based on
Cavusgnathus
and
Mestognathus
are difficult to correlate. An extinction event near the base of the Pennsylvanian was followed by the appearance of new gnathodid genera:
Rhachistognathus
,
Declinognathodus
,
Neognathodus
,
Idiognathoides
and
Idiognathodus
. By the middle of the Moscovian, few genera remained:
Idiognathodus
,
Neognathodus
and
Swadelina.
During the middle Kasimovian and Gzhelian, only
Idiognathodus
and
Streptognathodus
species were common. Near the end of the Gzhelian, a rediversification of
Streptognathodus
species extended into the Cisuralian.
How Impactful Is Presentation in Email? The Effect of Avatars and Signatures
Authors: Hailpern Joshua , Huber Mark , Calvo Ronald
Published: November 2020

A primary well-controlled study of 900 participants found that personal presentation choices in professional emails (non-content changes like Profile Avatar 8 Signature) impact the recipient’s perception of the sender’s personality and the quality of the email itself. By understanding the role these choices play, employees can gain better control over how they influence the recipient of their messages. Results further indicate that although some variations can positively impact the recipient’s view of the sender, these same variations often also have negative side effects. This implies that many seemingly innocuous presentation decisions should be made in the context of who is receiving the email, and if these effects negatively impact the content of the message. For example, although statements in a Signature about the email having been written on a phone are included to preemptively apologize for typing mistakes, this causes the sender to appear less agreeable, less conscientious, and less open, and the email itself appears less well written and more poorly formatted. This is surprising given that the email itself was not changed in the study.
Bayesian Nonparametric Unsupervised Concept Drift Detection for Data Stream Mining
Authors: Xuan Junyu , Lu Jie , Zhang Guangquan
Published: November 2020

Online data stream mining is of great significance in practice because of its ubiquity in many real-world scenarios, especially in the big data era. Traditional data mining algorithms cannot be directly applied to data streams due to (1) the possible change of underlying data distribution over time (i.e.,concept drift) and (2) delayed, short, or even no labels for streaming data in practice. A new research area, namedunsupervised concept drift detection, has emerged to tackle this difficulty mainly based on two-sample hypothesis tests, such as the Kolmogorov–Smirnov test. However, it is surprising that none of the existing methods in this area exploit the Bayesian nonparametric hypothesis test, which has clear interpretability and straightforward prior knowledge encoding ability and no strict or unrealistic requirement of prefixing the form for the underlying data distribution. In this article, we present a Bayesian nonparametric unsupervised concept drift detection method based on the Polya tree hypothesis test. The basic idea is to decompose the underlying data distribution into a multi-resolution representation that transforms the whole distribution hypothesis test into recursive and simple binomial tests. Also, an incremental mechanism is especially designed to improve its efficiency in the stream setting. The method effectively detect drifts, and it also locates where a drift happens and the posteriors of hypotheses. The experiments on synthetic data verify the desired properties of the proposed method, and the experiments on real-world data show the better performance of the method for data stream mining compared with its frequentist counterpart in the literature.
Type Inference for C
Authors: Melo Leandro T. C. , Ribeiro Rodrigo G. , Guimarães Breno C. F. , Pereira Fernando Magno Quintão
Published: November 2020

Type inference is a feature that is common to a variety of programming languages. While, in the past, it has been prominently present in functional ones (e.g., ML and Haskell), today, many object-oriented/multi-paradigm languages such as C# and C++ offer, to a certain extent, such a feature. Nevertheless, type inference still is an unexplored subject in the realm of C. In particular, it remains open whether it is possible to devise a technique that encompasses the idiosyncrasies of this language. The first difficulty encountered when tackling this problem is that parsing C requires, not only syntactic, but also semantic information. Yet, greater challenges emerge due to C’s intricate type system. In this work, we present a unification-based framework that lets us infer the missing struct, union, enum, and typedef declarations in a program.

As an application of our technique, we investigate the reconstruction of partial programs. Incomplete source code naturally appears in software development: during design and while evolving, testing, and analyzing programs; therefore, understanding it is a valuable asset. With a reconstructed well-typed program, one can: (i) enable static analysis tools in scenarios where components are absent; (ii) improve precision of “zero setup” static analysis tools; (iii) apply stub generators, symbolic executors, and testing tools on code snippets; and (iv) provide engineers with an assortment of compilable benchmarks for performance and correctness validation. We evaluate our technique on code from a variety of C libraries, including GNU’s Coreutils and on snippets from popular projects such as CPython, FreeBSD, and Git.
Fixpoints for the masses: programming with first-class Datalog constraints
Authors: Madsen Magnus , Lhoták Ondřej
Published: November 2020

Datalog is a declarative logic programming language that has been used in a variety of applications, including big-data analytics, language processing, networking and distributed systems, and program analysis.

In this paper, we propose first-class Datalog constraints as a mechanism to construct, compose, and solve Datalog programs at run time. The benefits are twofold: We gain the full power of a functional programming language to operate on Datalog constraints-as-values, while simultaneously we can use Datalog where it really shines: to declaratively express and solve fixpoint problems.

We present an extension of the lambda calculus with first-class Datalog constraints, including its semantics and a type system with row polymorphism based on Hindley-Milner. We prove soundness of the type system and implement it as an extension of the Flix programming language.
Effects as capabilities: effect handlers and lightweight effect polymorphism
Authors: Brachthäuser Jonathan Immanuel , Schuster Philipp , Ostermann Klaus
Published: November 2020

Effect handlers have recently gained popularity amongst programming language researchers. Existing type- and effect systems for effect handlers are often complicated and potentially hinder a wide-spread adoption.

We present the language Effekt with the goal to close the gap between research languages with effect handlers and languages for working programmers. The design of Effekt revolves around a different view of effects and effect types. Traditionally, effect types express which
side effects
a computation might have. In Effekt, effect types express which
capabilities
a computation requires from its context. While this new point in the design space of effect systems impedes reasoning about purity, we demonstrate that it simplifies the treatment of effect polymorphism and the related issues of effect parametricity and effect encapsulation. To guarantee effect safety, we separate functions from values and treat
all
functions as second-class. We define the semantics of Effekt as a translation to System Xi, a calculus in explicit capability-passing style.
Automated policy synthesis for system call sandboxing
Authors: Pailoor Shankara , Wang Xinyu , Shacham Hovav , Dillig Isil
Published: November 2020

System call whitelisting is a powerful sandboxing approach that can significantly reduce the capabilities of an attacker if an application is compromised. Given a
policy
that specifies which system calls can be invoked with what arguments, a sandboxing framework terminates any execution that violates the policy. While this mechanism greatly reduces the attack surface of a system, manually constructing these policies is time-consuming and error-prone. As a result, many applications —including those that take untrusted user input— opt not to use a system call sandbox.

Motivated by this problem, we propose a technique for automatically constructing system call whitelisting policies for a given application and policy DSL. Our method combines static code analysis and program synthesis to construct
sound and precise policies
that never erroneously terminate the application, while restricting the program’s system call usage as much as possible. We have implemented our approach in a tool called Abhayaand experimentally evaluate it 493 Linux and OpenBSD applications by automatically synthesizing Seccomp-bpfand Pledgepolicies. Our experimental results indicate that Abhayacan efficiently generate useful and precise sandboxes for real-world applications.
Towards a unified proof framework for automated fixpoint reasoning using matching logic
Authors: Chen Xiaohong , Trinh Minh-Thai , Rodrigues Nishant , Peña Lucas , Roşu Grigore
Published: November 2020

Automation of fixpoint reasoning has been extensively studied for various mathematical structures, logical formalisms, and computational domains, resulting in specialized fixpoint provers for heaps, for streams, for term algebras, for temporal properties, for program correctness, and for many other formal systems and inductive and coinductive properties. However, in spite of great theoretical and practical interest, there is no unified framework for automated fixpoint reasoning. Although several attempts have been made, there is no evidence that such a unified framework is possible, or practical. In this paper, we propose a candidate based on matching logic, a formalism recently shown to theoretically unify the above mentioned formal systems. Unfortunately, the (Knaster-Tarski) proof rule of matching logic, which enables inductive reasoning, is not syntax-driven. Worse, it can be applied at any step during a proof, making automation seem hopeless. Inspired by recent advances in automation of inductive proofs in separation logic, we propose an alternative proof system for matching logic, which is amenable for automation. We then discuss our implementation of it, which although not superior to specialized state-of-the-art automated provers for specific domains, we believe brings some evidence and hope that a unified framework for automated reasoning is not out of reach.
Build scripts with perfect dependencies
Authors: Spall Sarah , Mitchell Neil , Tobin-Hochstadt Sam
Published: November 2020

Build scripts for most build systems describe the actions to run, and the dependencies between those actions - but often build scripts get those dependencies wrong. Most build scripts have both too few dependencies (leading to incorrect build outputs) and too many dependencies (leading to excessive rebuilds and reduced parallelism). Any programmer who has wondered why a small change led to excess compilation, or who resorted to a clean step, has suffered the ill effects of incorrect dependency specification. We outline a build system where dependencies are not specified, but instead captured by tracing execution. The consequence is that dependencies are always correct by construction and build scripts are easier to write. The simplest implementation of our approach would lose parallelism, but we are able to recover parallelism using speculation.
Perfectly parallel fairness certification of neural networks
Authors: Urban Caterina , Christakis Maria , Wüstholz Valentin , Zhang Fuyuan
Published: November 2020

Recently, there is growing concern that machine-learned software, which currently assists or even automates decision making, reproduces, and in the worst case reinforces, bias present in the training data. The development of tools and techniques for certifying fairness of this software or describing its biases is, therefore, critical. In this paper, we propose a perfectly parallel static analysis for certifying fairness of feed-forward neural networks used for classification of tabular data. When certification succeeds, our approach provides definite guarantees, otherwise, it describes and quantifies the biased input space regions. We design the analysis to be sound, in practice also exact, and configurable in terms of scalability and precision, thereby enabling pay-as-you-go certification. We implement our approach in an open-source tool called Libra and demonstrate its effectiveness on neural networks trained on popular datasets.
Detecting locations in JavaScript programs affected by breaking library changes
Authors: Møller Anders , Nielsen Benjamin Barslev , Torp Martin Toldam
Published: November 2020

JavaScript libraries are widely used and evolve rapidly. When adapting client code to non-backwards compatible changes in libraries, a major challenge is how to locate affected API uses in client code, which is currently a difficult manual task. In this paper we address this challenge by introducing a simple pattern language for expressing API access points and a pattern-matching tool based on lightweight static analysis.

Experimental evaluation on 15 popular npm packages shows that typical breaking changes are easy to express as patterns. Running the static analysis on 265 clients of these packages shows that it is accurate and efficient: it reveals usages of breaking APIs with only 14% false positives and no false negatives, and takes less than a second per client on average. In addition, the analysis is able to report its confidence, which makes it easier to identify the false positives. These results suggest that the approach, despite its simplicity, can reduce the manual effort of the client developers.
On the unusual effectiveness of type-aware operator mutations for testing SMT solvers
Authors: Winterer Dominik , Zhang Chengyu , Su Zhendong
Published: November 2020

We propose type-aware operator mutation, a simple, but unusually effective approach for testing SMT solvers. The key idea is to mutate operators of conforming types within the seed formulas to generate well-typed mutant formulas. These mutant formulas are then used as the test cases for SMT solvers. We realized type-aware operator mutation within the OpFuzz tool and used it to stress-test Z3 and CVC4, two state-of-the-art SMT solvers. Type-aware operator mutations are unusually effective: During one year of extensive testing with OpFuzz, we reported 1092 bugs on Z3’s and CVC4’s respective GitHub issue trackers, out of which 819 unique bugs were confirmed and 685 of the confirmed bugs were fixed by the developers. The detected bugs are highly diverse — we found bugs of many different types (soundness bugs, invalid model bugs, crashes, etc.), logics and solver configurations. We have further conducted an in-depth study of the bugs found by OpFuzz. The study results show that the bugs found by OpFuzz are of high quality. Many of them affect core components of the SMT solvers’ codebases, and some required major changes for the developers to fix. Among the 819 confirmed bugs found by OpFuzz,184 were soundness bugs, the most critical bugs in SMT solvers,and 489 were in the default modes of the solvers. Notably, OpFuzz found 27 critical soundness bugs in CVC4, which has proved to be a very stable SMT solver.
Fast linear programming through transprecision computing on small and sparse data
Authors: Grosser Tobias , Theodoridis Theodoros , Falkenstein Maximilian , Pitchanathan Arjun , Kruse Michael , Rigger Manuel , Su Zhendong , Hoefler Torsten
Published: November 2020

A plethora of program analysis and optimization techniques rely on linear programming at their heart. However, such techniques are often considered too slow for production use. While today’s best solvers are optimized for complex problems with thousands of dimensions, linear programming, as used in compilers, is typically applied to small and seemingly trivial problems, but to many instances in a single compilation run. As a result, compilers do not benefit from decades of research on optimizing large-scale linear programming. We design a simplex solver targeted at compilers. A novel theory of transprecision computation applied from individual elements to full data-structures provides the computational foundation. By carefully combining it with optimized representations for small and sparse matrices and specialized small-coefficient algorithms, we (1) reduce memory traffic, (2) exploit wide vectors, and (3) use low-precision arithmetic units effectively. We evaluate our work by embedding our solver into a state-of-the-art integer set library and implement one essential operation, coalescing, on top of our transprecision solver. Our evaluation shows more than an order-of-magnitude speedup on the core simplex pivot operation and a mean speedup of 3.2x (vs. GMP) and 4.6x (vs. IMath) for the optimized coalescing operation. Our results demonstrate that our optimizations exploit the wide SIMD instructions of modern microarchitectures effectively. We expect our work to provide foundations for a future integer set library that uses transprecision arithmetic to accelerate compiler analyses.
Scalable and serializable networked multi-actor programming
Authors: Sang Bo , Eugster Patrick , Petri Gustavo , Ravi Srivatsan , Roman Pierre-Louis
Published: November 2020

A major challenge in writing applications that execute across hosts, such as distributed online services, is to reconcile (a) parallelism (i.e., allowing components to execute independently on disjoint tasks), and (b)cooperation (i.e., allowing components to work together on common tasks). A good compromise between the two is vital to scalability, a core concern in distributed networked applications.

The actor model of computation is a widely promoted programming model for distributed applications, as actors can execute in individual threads (parallelism) across different hosts and interact via asynchronous message passing (collaboration). However, this makes it hard for programmers to reason about combinations of messages as opposed to individual messages, which is essential in many scenarios.

This paper presents a pragmatic variant of the actor model in which messages can be grouped into units that are executed in a serializable manner, whilst still retaining a high degree of parallelism. In short, our model is based on an orchestration of actors along a directed acyclic graph that supports efficient decentralized synchronization among actors based on their actual interaction. We present the implementation of this model, based on a dynamic DAG-inducing referencing discipline, in the actor-based programming language AEON. We argue serializability and the absence of deadlocks in our model, and demonstrate its scalability and usability through extensive evaluation and case studies of wide-ranging applications.
Towards Automatic Image Exposure Level Assessment
Authors: Zhang Lin , Yang Xilin , Zhang Lijun , Liu Xiao , Zhao Shengjie , Ma Yong
Published: November 2020

The quality of acquired images can be surely reduced by improper exposures. Thus, in many vision-related industries, such as imaging sensor manufacturing and video surveillance, an approach that can routinely and accurately evaluate exposure levels of images is in urgent need. Taking an image as input, such a method is expected to output a scalar value, which can represent the overall perceptual exposure level of the examined image, ranging from extremely underexposed to extremely overexposed. However, studies focusing on image exposure level assessment (IELA) are quite sporadic. It should be noted that blind NR-IQA (no-reference image quality assessment) algorithms or metrics used to measure the quality of contrast-distorted images cannot be used for IELA. The root reason is that though these algorithms can quantify quality distortion of images, they do not know whether the distortion is due to underexposure or overexposure. This paper aims to resolve the issue of IELA to some extent and contributes to two aspects. Firstly, an Image Exposure Database (IEpsD) is constructed to facilitate the study of IELA. IEpsD comprises 24,500 images with various exposure levels, and for each image a subjective exposure score is provided, which represents its perceptual exposure level. Secondly, as IELA can be naturally formulated as a regression problem, we thoroughly evaluate the performance of modern deep CNN architectures for solving this specific task. Our evaluation results can serve as a baseline when the other researchers develop even more sophisticated IELA approaches. To facilitate the other researchers to reproduce our results, we have released the dataset and the relevant source code at https://cslinzhang.github.io/imgExpo/.
Hyponatraemia as a Predictor of Mortality in Medical Admissions in Ghana: A Comparative Study
Authors: Tannor Elliot Koranteng , Agyei Martin , Tannor Abena Y. , Ofori Afua , Akumiah Emmanuel , Boateng Yasmin Adoma
Published: November 2020

Background. Hyponatraemia is the most common electrolyte abnormality in hospital admissions. It occurs in a quarter of medical admissions in Ghana, and it is associated with high mortality. Mortality has been suggested to be due to the underlying medical condition and not necessarily the hyponatraemia. We set out to compare the outcomes of patients with documented hyponatraemia as compared to those with normonatraemia in terms of mortality and length of hospital stay. Methods. We conducted a comparative analysis of patients with hyponatraemia and those with normonatraemia on the medical ward at the Komfo Anokye Teaching Hospital between May 2018 and December 2018. The medical diagnoses, demographics, and laboratory data of the patients were recorded. Participants’ age and gender were matched. Student’s t-test was used to test for differences in continuous variables when parametric and Wilcoxon signed-rank test for nonparametric variables. Multiple logistic regression was used to identify predictors of in-hospital mortality. Apvalue of <0.05 was considered statistically significant. Results. Within the study period, 846 patients with documented serum sodium were included in the study. The study involved 406 patients with hyponatraemia and 440 patients with normonatraemia. Serum albumin and protein were significantly lower in the hyponatraemia patients as compared to those with normonatraemia. The mortality rate in patients with hyponatraemia was significantly higher than those with normonatraemia (129 (31.8%) vs. 9 (22.3%); OR 1.62 (95% CI: 1.19–2.22),p=0.002). In-hospital stay was longer in patients with hyponatraemia than normonatraemia (7 (4–10) vs. 6 (3–10) days) but not statistically significantp=0.09. Multiple logistic regression showed that low serum sodiump<0.001and low serum albuminp=0.009were the predictors of in-hospital mortality. Conclusion. Hyponatraemia is associated with significantly higher mortality than normonatraemia and predicts worse prognosis in patients on medical admission. Low serum albumin is also a predictor of mortality in medical admission.
Delays in Diagnosis of Pulmonary Lymphangitic Carcinomatosis due to Benign Presentation
Authors: Pandey Swati , Ojha Shishir
Published: November 2020

The diagnosis of lymphangitic carcinomatosis is challenging due to the manifestation of nonspecific symptoms and radiographic abnormalities that bear similarity to those of interstitial lung disease. Herein, we report the case of a 53-year-old woman diagnosed with lymphangitic carcinomatosis from metastatic gastric adenocarcinoma, 3 months after her initial presentation.
Chloride Ingress in Cement Mortars Exposed to Acidithiobacillus thiooxidans Bacteria
Authors: Munyao Onesmus Mulwa , Thiong’o Joseph Karanja , Wachira Jackson Muthengia , Mutitu Daniel Karanja , Murithi Genson , Mwirichia Romano
Published: November 2020

Concrete structures placed in aggressive aqueous environments are vulnerable to degradation. Majority of studies have linked structural failures to the ingress of deleterious ions into the cement matrix. Some microbial activities may accelerate the penetration of harmful materials into the cement matrix and hence cause pronounced deterioration. This work reports a laboratory‐simulated study carried out to determine the extent of chloride ingress in cement mortars exposed to Acidithiobacillus thiooxidans. Test prisms were cast from Portland pozzolana cement (PPC) and ordinary Portland cement (OPC) with water‐to‐cement ratio maintained at 0.5. Acidithiobacillus thiooxidans bacterial solution of concentration 1.0 × 107 cell/mL was used to prepare microbial mortar prisms, whereas distilled water was used to prepare the control mortar prisms. The test prisms were subjected to porosity and accelerated chloride ingress after 28th day of curing. Compressive strength was determined after the 2nd, 7th, 28th, and 56th days of curing. Apparent diffusion coefficients (Dapp) were estimated from the solutions to Fick’s second law of diffusion. After the 56th day of curing, the microbial‐treated mortars exhibited a significant reduction in compressive strength. The resultant percentage decrease in compressive strength was 30.74% and 19.88% for OPC and PPC, respectively. Further, microbial‐treated mortars demonstrated both high porosity and chloride ingress as compared to the control test mortars. Scanning electron microscopy (SEM) and X‐ray diffraction (XRD) analyses showed the formation of new deleterious products in the microbial‐exposed mortars.
The Temperature Evaluation of the Buried Hill Geothermal Reservoirs in the Jizhong Depression, Bohai Bay Basin, China
Authors: Dong Yuyang , Zeng Jianhui , Zhao Xianzheng , Wang Yanu , Chen Tianhao , Zhang Yongchao , Feng Sen
Published: November 2020

The Jizhong Depression is located in the western Bohai Bay Basin, eastern China. The deep strata are mainly composed of carbonate buried hill, and the shallow strata are a mainly siliciclastic deposition. In the present work, the Na-K-Mg triangle diagram and geothermometers were used to investigate the geochemical characteristics of shallow groundwater and reservoir temperature features of three geothermal reservoirs in the depression, including the Ordovician, the Cambrian, and the Precambrian Wumishan Formation. The results showed that the geothermal water in the depression could be divided into three groups: group I, Cl·

HCO

3

-Na type; group II, Cl-Na type; and group III, Cl-Na·Ca type. By using the Na-K-Mg triangle diagram, group II and group III geothermal water samples were identified as the partially equilibrated water, whose temperature of the geothermal reservoir can be calculated based on the cation geothermometers. The ranges of the calculated temperature of the shallow strata and the deep strata are 91~146°C and 147~176°C, respectively. It has the good results obtained with some cation geothermometers in a geothermal system hosted in carbonate rocks like the studied area. The analysis workflow and calculation data obtained in this work contribute to the evaluation of the temperature field and the exploration and development of the geothermal resources in the Bohai Bay Basin.
Efficacy and Prognostic Factors for Y-90 Radioembolization (Y-90) in Metastatic Neuroendocrine Tumors with Liver Metastases
Authors: Tsang Erica S. , Loree Jonathan M. , Davies Janine M. , Gill Sharlene , Liu David , Ho Stephen , Renouf Daniel J. , Lim Howard J. , Kennecke Hagen F.
Published: November 2020

Background. Yttrium-90 (Y-90) can be an effective liver-directed therapy for patients with metastatic neuroendocrine tumors (NETs), but population-based data are limited. We characterized the use of Y-90 in NET patients and identified factors associated with response. Methods. We identified 49 patients with metastatic liver-dominant NETs across BC Cancer’s six regional centres who received Y-90 between June 2011 and January 2017 in British Columbia, Canada. Baseline characteristics, radiographic responses, and outcomes were summarized. Results. Of the 49 patients who received Y-90, the median age was 56 years (range 21–78), 49% were male, and 94% had an ECOG performance status of 0–1. The primary location of the NET included pancreas (31%), small bowel (41%), large bowel (6%), unknown (14%), and others (12%). 69% of these patients had liver metastases alone, and tumors were graded as G1 (61%), G2 (25%), G3 (2%), and unknown (12%). Prior therapies included surgery (63%), local ablative therapy (25%), somatostatin analogue (69%), and systemic therapy (35%). The median Y-90 dose was 2.2 GBq (range 0.8–3.6), as SIR-spheres (69%) or TheraSpheres (29%). Median time to Y-90 from diagnosis of metastases measured 1.54 years. 88% received segmental Y-90, with 1 (69%), 2 (29%), and 3 (2%) treatments. Y-90 resulted in partial response (53%), stable disease (33%), and progressive disease (12%). Y-90 was well-tolerated, with infrequent grade 3-4 biochemical toxicities (2%) and grade 3 abdominal pain (6%). Longer overall survival (OS) was associated with resection of primary tumor, well-differentiated histology, and low Ki-67. Median OS was 27.2 months (95% CI 8.0–46.5).Conclusions. In our population-based cohort, Y-90 was well-tolerated in patients with metastatic liver-dominant NETs. Prior surgical resection was an important predictor of OS.
Dynamic Response of Composite Lining Tunnel with Buffer Layer: An Analytical and Experimental Investigation
Authors: Fan Kaixiang , Shen Yusheng , Wang Shuaishuai , Gao Bo , Zheng Qing , Yan Gaoming , Min Peng
Published: November 2020

Composite lining is often designed for the mountainous tunnels in high-intensity earthquake areas. The application of the buffer layer will bring more advantages, while the shock-absorbing mechanism is still unclear currently. In this paper, based on the Fourier-Bessel series expansion method, the dynamic stress concentration factor of composite lining tunnel with buffer layer subjected to plane SV waves in the half-space is obtained. Then, the influence of geometric and mechanical parameters of the buffer layer on composite lining was systematically analyzed. Finally, the correctness of the analytical solutions is verified by series shaking table tests and numerical simulations. Results suggest that the buffer layer can play the role of “redistributing” the seismic load, and it can effectively reduce the dynamic responses of secondary lining but amplify in primary support. There is an optimal interval of the stiffness and thickness for the buffer layer. When the stiffness ratio of the buffer layer to surrounding rock is 1/10 ∼ 1/50 or the ratio of buffer layer thickness to inner diameters of secondary lining is 1/40 ∼ 1/20, the shock-absorbing performance is remarkable. The general damage observations in tests show that the crown, arch springing, and invert of composite lining in case of no buffer layer are prone to cracking under a strong earthquake. The invert of the composite lining is more susceptible to be damaged after adopting the buffer layer. In general, the analytical results were consistent with experimental and numerical results. The above study results may provide theoretical support and experimental data for the seismic design of composite lining tunnels.
Distance Measurements Related to Cartesian Product of Cycles
Authors: Qiang Xiaoli , Nazeer Saima , Chu Yu-Ming , Umar Muhammad Awais , Kousar Imrana , Sehar Ammara
Published: November 2020

Graph theory and its wide applications in natural sciences and social sciences open a new era of research. Making the graph of computer networks and analyzing it with aid of graph theory are extensively studied and researched in the literature. An important discussion is based on distance between two nodes in a network which may include closeness of objects, centrality of objects, average path length between objects, and vertex eccentricity. For example, (1) disease transmission networks: closeness and centrality of objects are used to measure vulnerability to particular disease and its infectivity; (2) routing networks: eccentricity of objects is used to find vertices which form the periphery objects of the network. In this manuscript, we have discussed distance measurements including center, periphery, and average eccentricity for the Cartesian product of two cycles. The results are obtained using the definitions of eccentricity, radius, and diameter of a graph, and all possible cases (for different parity of length of cycles) have been proved.
Study on the Stability of a Transition Section from Soft to Hard Surrounding Rock Based on the Solid‐Fluid Coupling Effect
Authors: Hu Qizhi , Tang Yixin , Ding Zhigang
Published: November 2020

To study the stability of a transition section of a tunnel from soft to hard surrounding rock under seepage conditions, FLAC3D software was used to numerically simulate the transition section of the Laomushan Tunnel from the Shiqian to Yuping (Dalong) Expressways in Guizhou Province, China, and to explore different working conditions. The characterization of the tunnel seepage field, stress field, and displacement field and the analysis of the force of the primary lining support structure describe the influence of the seepage field on the stress field distribution and displacement field changes. The reliability of the calculation results is verified by comparison with displacement measurements collected during field monitoring. The design values of the primary support structure parameters of the transition section from soft to hard surrounding rock of the Laomushan Tunnel basically met the strength requirements. The research results provide references for the design and construction of similar projects.
Effect of Bainite Volume Fraction on Deformability of Mesostructures for Ferrite/Bainite Dual‐Phase Steel
Authors: Qiao Gui-ying , Zhao Zhong-tao , Shi Xian-bo , Wang Jun-si , Xiao Fu-ren
Published: November 2020

To obtain high strength and excellent deformability for ferrite/bainite dual‐phase (F/B DP) pipeline steel for gas pipelines based on strain‐based design, the volume fractions of ferrite and bainite should be considered first. In this work, abstract representative volume elements (RVE) of finite element models (FEMs) of mesostructure for F/B DP pipeline steel with volume fractions of bainite between 30% and 58% were established, and the effects of volume fraction of bainite on the tensile properties and deformation compatibility were studied. Results show that the stress and strain in the mesostructure were primarily distributed in the bainite and ferrite, respectively, and strain concentration occurs at the ferrite/bainite interface. With increasing volume fractions of bainite, the strain localization factor (SLF) and strain ratio of ferrite with bainite (εF/εB) decrease, which can improve the deformation compatibility of the F/B DP pipeline steel. However, the stress ratio of bainite with ferrite (σB/σF) and the contributions of bainite to stress and strain sequentially increase, and, as a result, the strength increases and the ductility decreases. Therefore, a balance of strength and deformability can be obtained when the optimal volume fraction of bainite is in the range of 40% to 48%.