bluuebunny/crossref_metadata_2025 huggingface dataset:
VirtCL: a framework for OpenCL device abstraction and management
Authors: You Yi-Ping , Wu Hen-Jung , Tsai Yeh-Ning , Chao Yen-Ting
Published: December 2015

The interest in using multiple graphics processing units (GPUs) to accelerate applications has increased in recent years. However, the existing heterogeneous programming models (e.g., OpenCL) abstract details of GPU devices at the per-device level and require programmers to explicitly schedule their kernel tasks on a system equipped with multiple GPU devices. Unfortunately, multiple applications running on a multi-GPU system may compete for some of the GPU devices while leaving other GPU devices unused. Moreover, the distributed memory model defined in OpenCL, where each device has its own memory space, increases the complexity of managing the memory among multiple GPU devices. In this article we propose a framework (called VirtCL) that reduces the programming burden by acting as a layer between the programmer and the native OpenCL run-time system for abstracting multiple devices into a single virtual device and for scheduling computations and communications among the multiple devices. VirtCL comprises two main components: (1) a front-end library, which exposes primary OpenCL APIs and the virtual device, and (2) a back-end run-time system (called CLDaemon) for scheduling and dispatching kernel tasks based on a history-based scheduler. The front-end library forwards computation requests to the back-end CLDaemon, which then schedules and dispatches the requests. We also propose a history-based scheduler that is able to schedule kernel tasks in a contention- and communication-aware manner. Experiments demonstrated that the VirtCL framework introduced a small overhead (mean of 6%) but outperformed the native OpenCL run-time system for most benchmarks in the Rodinia benchmark suite, which was due to the abstraction layer eliminating the time-consuming initialization of OpenCL contexts. We also evaluated different scheduling policies in VirtCL with a real-world application (clsurf) and various synthetic workload traces. The results indicated that the VirtCL framework provides scalability for multiple kernel tasks running on multi-GPU systems.
SYNC or ASYNC: time to fuse for distributed graph-parallel computation
Authors: Xie Chenning , Chen Rong , Guan Haibing , Zang Binyu , Chen Haibo
Published: December 2015

Large-scale graph-structured computation usually exhibits iterative and convergence-oriented computing nature, where input data is computed iteratively until a convergence condition is reached. Such features have led to the development of two different computation modes for graph-structured programs, namely synchronous (Sync) and asynchronous (Async) modes. Unfortunately, there is currently no in-depth study on their execution properties and thus programmers have to manually choose a mode, either requiring a deep understanding of underlying graph engines, or suffering from suboptimal performance. This paper makes the first comprehensive characterization on the performance of the two modes on a set of typical graph-parallel applications. Our study shows that the performance of the two modes varies significantly with different graph algorithms, partitioning methods, execution stages, input graphs and cluster scales, and no single mode consistently outperforms the other. To this end, this paper proposes Hsync, a hybrid graph computation mode that adaptively switches a graph-parallel program between the two modes for optimal performance. Hsync constantly collects execution statistics on-the-fly and leverages a set of heuristics to predict future performance and determine when a mode switch could be profitable. We have built online sampling and offline profiling approaches combined with a set of heuristics to accurately predicting future performance in the two modes. A prototype called PowerSwitch has been built based on PowerGraph, a state-of-the-art distributed graph-parallel system, to support adaptive execution of graph algorithms. On a 48-node EC2-like cluster, PowerSwitch consistently outperforms the best of both modes, with a speedup ranging from 9% to 73% due to timely switch between two modes.
A framework for practical parallel fast matrix multiplication
Authors: Benson Austin R. , Ballard Grey
Published: December 2015

Matrix multiplication is a fundamental computation in many scientific disciplines. In this paper, we show that novel fast matrix multiplication algorithms can significantly outperform vendor implementations of the classical algorithm and Strassen's fast algorithm on modest problem sizes and shapes. Furthermore, we show that the best choice of fast algorithm depends not only on the size of the matrices but also the shape. We develop a code generation tool to automatically implement multiple sequential and shared-memory parallel variants of each fast algorithm, including our novel parallelization scheme. This allows us to rapidly benchmark over 20 fast algorithms on several problem sizes. Furthermore, we discuss a number of practical implementation issues for these algorithms on shared-memory machines that can direct further research on making fast algorithms practical.
The SprayList: a scalable relaxed priority queue
Authors: Alistarh Dan , Kopinsky Justin , Li Jerry , Shavit Nir
Published: December 2015

High-performance concurrent priority queues are essential for applications such as task scheduling and discrete event simulation. Unfortunately, even the best performing implementations do not scale past a number of threads in the single digits. This is because of the sequential bottleneck in accessing the elements at the head of the queue in order to perform a DeleteMin operation. In this paper, we present the SprayList, a scalable priority queue with relaxed ordering semantics. Starting from a non-blocking SkipList, the main innovation behind our design is that the DeleteMin operations avoid a sequential bottleneck by ``spraying'' themselves onto the head of the SkipList list in a coordinated fashion. The spraying is implemented using a carefully designed random walk, so that DeleteMin returns an element among the first O(p log^3 p) in the list, with high probability, where p is the number of threads. We prove that the running time of a DeleteMin operation is O(log^3 p), with high probability, independent of the size of the list. Our experiments show that the relaxed semantics allow the data structure to scale for high thread counts, comparable to a classic unordered SkipList. Furthermore, we observe that, for reasonably parallel workloads, the scalability benefits of relaxation considerably outweigh the additional work due to out-of-order execution.
A hierarchical approach to reducing communication in parallel graph algorithms
Authors: Harshvardhan  , Amato Nancy M. , Rauchwerger Lawrence
Published: December 2015

Large-scale graph computing has become critical due to the ever-increasing size of data. However, distributed graph computations are limited in their scalability and performance due to the heavy communication inherent in such computations. This is exacerbated in scale-free networks, such as social and web graphs, which contain hub vertices that have large degrees and therefore send a large number of messages over the network. Furthermore, many graph algorithms and computations send the same data to each of the neighbors of a vertex. Our proposed approach recognizes this, and reduces communication performed by the algorithm without change to user-code, through a hierarchical machine model imposed upon the input graph. The hierarchical model takes advantage of locale information of the neighboring vertices to reduce communication, both in message volume and total number of bytes sent. It is also able to better exploit the machine hierarchy to further reduce the communication costs, by aggregating traffic between different levels of the machine hierarchy. Results of an implementation in the STAPL GL shows improved scalability and performance over the traditional level-synchronous approach, with 2.5×-8× improvement for a variety of graph algorithms at 12,000+ cores.
Are web applications ready for parallelism?
Authors: Radoi Cosmin , Herhut Stephan , Sreeram Jaswanth , Dig Danny
Published: December 2015

In recent years, web applications have become pervasive. Their backbone is JavaScript, the only programming language supported by all major web browsers. Most browsers run on desktop or mobile devices with parallel hardware. However, JavaScript is by design sequential, and current web applications make little use of hardware parallelism. Are web applications ready to exploit parallel hardware? We answer the question in two steps: First, we survey 174 web developers about the potential and challenges of using parallelism. Then, we study the performance and computation shape of a set of web applications that are representative for the emerging web. Our findings indicate that emerging web applications do have latent data parallelism, and JavaScript developers' programming style is not a significant impediment to exploiting this parallelism.
Foundational extensible corecursion: a proof assistant perspective
Authors: Blanchette Jasmin Christian , Popescu Andrei , Traytel Dmitriy
Published: December 2015

This paper presents a formalized framework for defining corecursive functions safely in a total setting, based on corecursion up-to and relational parametricity. The end product is a general corecursor that allows corecursive (and even recursive) calls under "friendly" operations, including constructors. Friendly corecursive functions can be registered as such, thereby increasing the corecursor's expressiveness. The metatheory is formalized in the Isabelle proof assistant and forms the core of a prototype tool. The corecursor is derived from first principles, without requiring new axioms or extensions of the logic.
Efficient communication and collection with compact normal forms
Authors: Yang Edward Z. , Campagna Giovanni , Ağacan Ömer S. , El-Hassany Ahmed , Kulkarni Abhishek , Newton Ryan R.
Published: December 2015

In distributed applications, the transmission of non-contiguous data structures is greatly slowed down by the need to serialize them into a buffer before sending. We describe Compact Normal Forms, an API that allows programmers to explicitly place immutable heap objects into regions, which can both be accessed like ordinary data as well as efficiently transmitted over the network. The process of placing objects into compact regions (essentially a copy) is faster than any serializer and can be amortized over a series of functional updates to the data structure in question. We implement this scheme in the Glasgow Haskell Compiler and show that even with the space expansion attendant with memory-oriented data structure representations, we achieve between x2 and x4 speedups on fast local networks with sufficiently large data structures.
Elaborating evaluation-order polymorphism
Authors: Dunfield Jana
Published: December 2015

We classify programming languages according to evaluation order: each language fixes one evaluation order as the default, making it transparent to program in that evaluation order, and troublesome to program in the other. This paper develops a type system that is impartial with respect to evaluation order. Evaluation order is implicit in terms, and explicit in types, with by-value and by-name versions of type connectives. A form of intersection type quantifies over evaluation orders, describing code that is agnostic over (that is, polymorphic in) evaluation order. By allowing such generic code, programs can express the by-value and by-name versions of a computation without code duplication. We also formulate a type system that only has by-value connectives, plus a type that generalizes the difference between by-value and by-name connectives: it is either a suspension (by name) or a "no-op" (by value). We show a straightforward encoding of the impartial type system into the more economical one. Then we define an elaboration from the economical language to a call-by-value semantics, and prove that elaborating a well-typed source program, where evaluation order is implicit, produces a well-typed target program where evaluation order is explicit. We also prove a simulation between evaluation of the target program and reductions (either by-value or by-name) in the source program. Finally, we prove that typing, elaboration, and evaluation are faithful to the type annotations given in the source program: if the programmer only writes by-value types, no by-name reductions can occur at run time.
Certified symbolic management of financial multi-party contracts
Authors: Bahr Patrick , Berthold Jost , Elsman Martin
Published: December 2015

Domain-specific languages (DSLs) for complex financial contracts are in practical use in many banks and financial institutions today. Given the level of automation and pervasiveness of software in the sector, the financial domain is immensely sensitive to software bugs. At the same time, there is an increasing need to analyse (and report on) the interaction between multiple parties. In this paper, we present a multi-party contract language that rigorously relegates any artefacts of simulation and computation from its core, which leads to favourable algebraic properties, and therefore allows for formalising domain-specific analyses and transformations using a proof assistant. At the centre of our formalisation is a simple denotational semantics independent of any stochastic aspects. Based on this semantics, we devise certified contract analyses and transformations. In particular, we give a type system, with an accompanying type inference procedure, that statically ensures that contracts follow the principle of causality. Moreover, we devise a reduction semantics that allows us to evolve contracts over time, in accordance with the denotational semantics. From the verified Coq definitions, we automatically extract a Haskell implementation of an embedded contract DSL along with the formally verified contract management functionality. This approach opens a road map towards more reliable contract management software, including the possibility of analysing contracts based on symbolic instead of numeric methods.
Practical principled FRP: forget the past, change the future, FRPNow!
Authors: Ploeg Atze van der , Claessen Koen
Published: December 2015

We present a new interface for practical Functional Reactive Programming (FRP) that (1) is close in spirit to the original FRP ideas, (2) does not have the original space-leak problems, without using arrows or advanced types, and (3) provides a simple and expressive way for performing IO actions from FRP code. We also provide a denotational semantics for this new interface, and a technique (using Kripke logical relations) for reasoning about which FRP functions may "forget their past", i.e. which functions do not have an inherent space-leak. Finally, we show how we have implemented this interface as a Haskell library called FRPNow.
A fast compiler for NetKAT
Authors: Smolka Steffen , Eliopoulos Spiridon , Foster Nate , Guha Arjun
Published: December 2015

High-level programming languages play a key role in a growing number of networking platforms, streamlining application development and enabling precise formal reasoning about network behavior. Unfortunately, current compilers only handle "local" programs that specify behavior in terms of hop-by-hop forwarding behavior, or modest extensions such as simple paths. To encode richer "global" behaviors, programmers must add extra state -- something that is tricky to get right and makes programs harder to write and maintain. Making matters worse, existing compilers can take tens of minutes to generate the forwarding state for the network, even on relatively small inputs. This forces programmers to waste time working around performance issues or even revert to using hardware-level APIs. This paper presents a new compiler for the NetKAT language that handles rich features including regular paths and virtual networks, and yet is several orders of magnitude faster than previous compilers. The compiler uses symbolic automata to calculate the extra state needed to implement "global" programs, and an intermediate representation based on binary decision diagrams to dramatically improve performance. We describe the design and implementation of three essential compiler stages: from virtual programs (which specify behavior in terms of virtual topologies) to global programs (which specify network-wide behavior in terms of physical topologies), from global programs to local programs (which specify behavior in terms of single-switch behavior), and from local programs to hardware-level forwarding tables. We present results from experiments on real-world benchmarks that quantify performance in terms of compilation time and forwarding table size.
Vectorization of apply to reduce interpretation overhead of R
Authors: Wang Haichuan , Padua David , Wu Peng
Published: December 2015

R is a popular dynamic language designed for statistical computing. Despite R's huge user base, the inefficiency in R's language implementation becomes a major pain-point in everyday use as well as an obstacle to apply R to solve large scale analytics problems. The two most common approaches to improve the performance of dynamic languages are: implementing more efficient interpretation strategies and extending the interpreter with Just-In-Time (JIT) compiler. However, both approaches require significant changes to the interpreter, and complicate the adoption by development teams as a result. This paper presents a new approach to improve execution efficiency of R programs by vectorizing the widely used Apply class of operations. Apply accepts two parameters: a function and a collection of input data elements. The standard implementation of Apply iteratively invokes the input function with each element in the data collection. Our approach combines data transformation and function vectorization to convert the looping-over-data execution of the standard Apply into a single invocation of a vectorized function that contains a sequence of vector operations over the input data. This conversion can significantly speed-up the execution of Apply operations in R by reducing the number of interpretation steps. We implemented the vectorization transformation as an R package. To enable the optimization, all that is needed is to invoke the package, and the user can use a normal R interpreter without any changes. The evaluation shows that the proposed method delivers significant performance improvements for a collection of data analysis algorithm benchmarks. This is achieved without any native code generation and using only a single-thread of execution.
Conditionally correct superoptimization
Authors: Sharma Rahul , Schkufza Eric , Churchill Berkeley , Aiken Alex
Published: December 2015

The aggressive optimization of heavily used kernels is an important problem in high-performance computing. However, both general purpose compilers and highly specialized tools such as superoptimizers often do not have sufficient static knowledge of restrictions on program inputs that could be exploited to produce the very best code. For many applications, the best possible code is conditionally correct: the optimized kernel is equal to the code that it replaces only under certain preconditions on the kernel's inputs. The main technical challenge in producing conditionally correct optimizations is in obtaining non-trivial and useful conditions and proving conditional equivalence formally in the presence of loops. We combine abstract interpretation, decision procedures, and testing to yield a verification strategy that can address both of these problems. This approach yields a superoptimizer for x86 that in our experiments produces binaries that are often multiple times faster than those produced by production compilers.
AutoMO: automatic inference of memory order parameters for C/C++11
Authors: Ou Peizhao , Demsky Brian
Published: December 2015

Many concurrent data structures are initially designed for the sequential consistency (SC) memory model. Developers often implement these data structures on real-world systems with weaker memory models by adding sufficient fences to ensure that their implementation on the weak memory model exhibits the same executions as the SC memory model. Recently, the C11 and C++11 standards have added a weak memory model to the C and C++ languages. Developing and debugging code for weak memory models can be extremely challenging. We present AutoMO, a framework to support porting data structures designed for the SC memory model to the C/C++11 memory model. AutoMO provides support across the porting process: (1) it automatically infers initial settings for the memory order parameters, (2) it detects whether a C/C++11 execution is equivalent to some SC execution, and (3) it simplifies traces to make them easier to understand. We have used AutoMO to successfully infer memory order parameters for a range of data structures and to check whether executions of several concurrent data structure implementations are SC.
Synthesis of layout engines from relational constraints
Authors: Hottelier Thibaud , Bodik Rastislav
Published: December 2015

We present an algorithm for synthesizing efficient document layout engines from compact relational specifications. These specifications are compact in that a single specification can produce multiple engines, each for a distinct layout situation, i.e., a different combination of known vs. unknown attributes. Technically, our specifications are relational attribute grammars, while our engines are functional attribute grammars. By synthesizing functions from relational constraints, we obviate the need for constraint solving at runtime, because functional attribute grammars can be easily evaluated according to a fixed schedule, sidestepping the backtracking search performed by constraint solvers. Our experiments show that we can generate layout engines for non-trivial data visualizations, and that our synthesized engines are between 39- and 200-times faster than general-purpose constraint solvers. Relational specifications of layout give rise to synthesis problems that have previously proved intractable. Our algorithm exploits the hierarchical, grammar-based structure of the specification, decomposing the specification into smaller subproblems, which can be tackled with off-the-shelf synthesis procedures. The new synthesis problem then becomes the composition of the functions thus generated into a correct attribute grammar, which might be recursive. We show how to solve this problem by efficient reduction to an SMT problem.
Fast, multicore-scalable, low-fragmentation memory allocation through large virtual memory and global data structures
Authors: Aigner Martin , Kirsch Christoph M. , Lippautz Michael , Sokolova Ana
Published: December 2015

We demonstrate that general-purpose memory allocation involving many threads on many cores can be done with high performance, multicore scalability, and low memory consumption. For this purpose, we have designed and implemented scalloc, a concurrent allocator that generally performs and scales in our experiments better than other allocators while using less memory, and is still competitive otherwise. The main ideas behind the design of scalloc are: uniform treatment of small and big objects through so-called virtual spans, efficiently and effectively reclaiming free memory through fast and scalable global data structures, and constant-time (modulo synchronization) allocation and deallocation operations that trade off memory reuse and spatial locality without being subject to false sharing.
SATCheck: SAT-directed stateless model checking for SC and TSO
Authors: Demsky Brian , Lam Patrick
Published: December 2015

Writing low-level concurrent code is well known to be challenging and error prone. The widespread deployment of multi-core hardware and the shift towards using low-level concurrent data structures has moved the problem into the mainstream. Finding bugs in such code may require finding a specific bug-revealing thread interleaving out of a huge space of parallel executions. Model-checking is a powerful technique for exhaustively testing code. However, scaling model checking presents a significant challenge. In this paper we present a new and more scalable technique for model checking concurrent code, based on concrete execution. Our technique observes concrete behaviors, builds a model of these behaviors, encodes the model in SAT, and leverages SAT solver technology to find executions that reveal new behaviors. It then runs the new execution, incorporates the newly observed behavior, and repeats the process until it has explored all reachable behaviors. We have implemented a prototype of our approach in the SATCheck tool. Our tool supports both the Total Store Ordering (TSO) and Sequentially Consistent (SC) memory models. We evaulate SATCheck by testing several concurrent data structure implementations and comparing its performance to the original DPOR stateless model checking algorithm implemented in CDSChecker, the source DPOR algorithm implemented in Nidhugg, and CheckFence. Our experiments show that SATCheck scales better than previous approaches while at the same time operating on concrete executions.
Automatic memory reclamation for lock-free data structures
Authors: Cohen Nachshon , Petrank Erez
Published: December 2015

Lock-free data-structures are widely employed in practice, yet designing lock-free memory reclamation for them is notoriously difficult. In particular, all known lock-free reclamation schemes are ``manual'' in the sense that the developer has to specify when nodes have retired and may be reclaimed. Retiring nodes adequately is non-trivial and often requires the modification of the original lock-free algorithm. In this paper we present an automatic lock-free reclamation scheme for lock-free data-structures in the spirit of a mark-sweep garbage collection. The proposed algorithm works with any normalized lock-free algorithm and with no need for the programmer to retire nodes or make changes to the algorithm. Evaluation of the proposed scheme on a linked-list and a hash table shows that it performs similarly to the best manual (lock-free) memory reclamation scheme.
RAIVE: runtime assessment of floating-point instability by vectorization
Authors: Lee Wen-Chuan , Bao Tao , Zheng Yunhui , Zhang Xiangyu , Vora Keval , Gupta Rajiv
Published: December 2015

Floating point representation has limited precision and inputs to floating point programs may also have errors. Consequently, during execution, errors are introduced, propagated, and accumulated, leading to unreliable outputs. We call this the instability problem. We propose RAIVE, a technique that identifies output variations of a floating point execution in the presence of instability. RAIVE transforms every floating point value to a vector of multiple values – the values added to create the vector are obtained by introducing artifi- cial errors that are upper bounds of actual errors. The propagation of artificial errors models the propagation of actual errors. When values in vectors result in discrete execution differences (e.g., following different paths), the execution is forked to capture the resulting output variations. Our evaluation shows that RAIVE can precisely capture output variations. Its overhead (340%) is 2.43 times lower than the state of the art
Staging of Primary Abdominal Lymphomas: Comparison of Whole-Body MRI with Diffusion-Weighted Imaging and18F-FDG-PET/CT
Authors: Stecco Alessandro , Buemi Francesco , Quagliozzi Martina , Lombardi Mariangela , Santagostino Alberto , Sacchetti Gian Mauro , Carriero Alessandro
Published: December 2015

Background. The purpose of this study was to compare the accuracy of whole-body MRI with diffusion-weighted sequences (WB-DW-MRI) with that of18F-FDG-PET/CT in the staging of patients with primary gastrointestinal lymphoma.Methods. This retrospective study involved 17 untreated patients with primary abdominal gastrointestinal lymphoma. All patients underwent18F-FDG-PET/CT and WB-DW-MRI. Histopathology findings or at least 6 months of clinical and radiological follow-up was the gold standard. The Musshoff-modified Ann Arbor system was used for staging, and diagnostic accuracy was evaluated on a per-node basis.Results. WB-DW-MRI exhibited 100% sensitivity, 96.3% specificity, and 96.1% and 100% positive and negative predictive values (PPV and NPV), respectively. The sensitivity, specificity, and PPV and NPV of PET/CT were 95.9%, 100%, and 100% and 96.4%, respectively. There were no statistically significant differences between the two techniquesp=0.05. The weighted kappa agreement statistics with a 95% confidence interval were 0.97 (0.95–0.99) between the two MRI readers and 0.87 (0.82–0.92) between the two methods.Conclusions. WB-DW-MRI appears to have a comparable diagnostic value to18F-FDG-PET/CT in staging patients with gastrointestinal lymphoma.
Serologic Intestinal-Fatty Acid Binding Protein in Necrotizing Enterocolitis Diagnosis: A Meta-Analysis
Authors: Cheng Shupeng , Yu Jialin , Zhou Min , Tu Yan , Lu Qi
Published: December 2015

Background. Previous studies showed that intestinal-fatty acid binding protein (I-FABP) may be a valid and promising serologic biomarker for early diagnosis of necrotizing enterocolitis (NEC).Objective. To investigate the early diagnostic value of serologic I-FABP in NEC for the premature neonates.Methods. All major databases were searched from January 1, 1990, to May 1, 2015. We used Meta-Disc 1.4 and Revman5.0 software to calculate the diagnostic accuracy.Results. Seven studies with 444 subjects were identified. The pooled sensitivity of I-FABP was 0.67 for NEC I, 0.74 for NEC II, and 0.83 for NEC III, and the pooled specificity was 0.84, respectively, which showed a moderate diagnostic accuracy. The area under curve (AUC) for each stage was 0.75 (Q⁎=0.69), 0.82 (Q⁎=0.76), and 0.91 (Q⁎=0.84). The diagnostic threshold analysis showed no significant difference in threshold effect. The metaregression showed that the cut-off value has the largest effect on heterogeneity. The funnel plots indicated the existence of publication bias.Conclusion. I-FABP is a valid serologic biomarker for early diagnosis in NEC for the premature neonates with a moderate accuracy.
An Experimental Study on Hybrid Noncompression CF Bracing and GF Sheet Wrapping Reinforcement Method to Restore Damaged RC Structures
Authors: Lee Kang Seok
Published: December 2015

We describe a novel technique for restoration of reinforced concrete (RC) structures that have sustained damage during an earthquake. The reinforcement scheme described here is a hybrid seismic retrofitting technique that combines noncompression X-bracing using CF with externally bonded GF sheets to strengthen RC structures that have sustained damage following an earthquake. The GF sheet is used to improve the ductility of columns, and the noncompression CF X-bracing system, which consists of CF bracing and anchors to replace the conventional steel bracing and bolt connections, is used to increase the lateral strength of the framing system. We report seismic restoration capacity, which enables reuse of the damaged RC frames via the hybrid CF X-bracing and GF sheet wrapping system. Cyclic loading tests were carried out to investigate hysteresis of the lateral load-drift relations, as well as the ductility. The GF sheet significantly improved the ductility of columns, resulting in a change in failure mode. The strengthening effect of conventional CF sheets used in columns is not sufficient with respect to lateral strength and stiffness. However, this study results in a significant increase in the strength of the structure due to the use of CF X-bracing and inhibited buckling failure of the bracing. This result can be exploited to develop guidelines for the application of the reinforcement system to restore damaged RC structures.
A Narrative Review on the Pathophysiology and Management for Radiation Cystitis
Authors: Browne C. , Davis N. F. , Mac Craith E. , Lennon G. M. , Mulvin D. W. , Quinlan D. M. , Mc Vey Gerard P. , Galvin D. J.
Published: December 2015

Radiation cystitis is a recognised complication of pelvic radiotherapy. Incidence of radiation cystitis ranges from 23 to 80% and the incidence of severe haematuria ranges from 5 to 8%. High quality data on management strategies for radiation cystitis is sparse. Treatment modalities are subclassified into systemic therapies, intravesical therapies, and hyperbaric oxygen and interventional procedures. Short-term cure rates range from 76 to 95% for hyperbaric oxygen therapy and interventional procedures. Adverse effects of these treatment strategies are acceptable. Ultimately, most patients require multimodal treatment for curative purposes. Large randomised trials exploring emergent management strategies are required in order to strengthen evidence-based treatment strategies. Urologists encounter radiation cystitis commonly and should be familiar with diagnostic modalities and treatment strategies.
Hypotensive and Angiotensin-Converting Enzyme Inhibitory Activities ofEisenia fetidaExtract in Spontaneously Hypertensive Rats
Authors: Mao Shumei , Li Chengde
Published: December 2015

Objectives. This study aimed to investigate the antihypertensive effects of anEisenia fetidaextract (EFE) and its possible mechanisms in spontaneously hypertensive rats (SHR rats).Methods. Sixteen-week-old SHR rats and Wistar-Kyoto rats (WKY rats) were used in this study. Rats were, respectively, given EFE (EFE group), captopril (captopril group), or phosphate-buffered saline (PBS) (normal control group and SHR group) for 4 weeks. ACE inhibitory activity of EFEin vitrowas determined. The systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured using a Rat Tail-Cuff Blood Pressure System. Levels of angiotensin II (Ang II), aldosterone (Ald), and 6-keto-prostaglandin F1 alpha (6-keto-PGF1α) in plasma were determined by radioimmunoassay, and serum nitric oxide (NO) concentration was measured by Griess reagent systems.Results. EFE had marked ACE inhibitory activityin vitro(IC50= 2.5 mg/mL). After the 4-week drug management, SHR rats in EFE group and in captopril group had lower SBP and DBP, lower levels of Ang II and Ald, and higher levels of 6-keto-PGF1αand NO than the SHR rats in SHR group.Conclusion. These results indicate that EFE has hypotensive effects in SHR rats and its effects might be associated with its ACE inhibitory activity.
Using Picture and Text Schedules to Inform Children: Effects on Distress and Pain during Needle-Related Procedures in Nitrous Oxide Sedation
Authors: Vantaa Benjaminsson Merja , Thunberg Gunilla , Nilsson Stefan
Published: December 2015

During hospital visits, children often undergo examinations and treatments that may involve an experience of pain and distress that is also connected to the staff’s treatment. The United Nation’s Convention on the Rights of Persons with Disability advocates the use of Universal Design. One way of implementing this idea within paediatric nursing is to increase the use of pictorial supports, and the few studies that have been published show promising results. The aim of this study was to do a comparison between two groups of children in regard to the pre- and postconditions of implementing an intervention including staff instruction and the use of pictorial support. The support consisted of a visual schedule with pictures and text, used both preparatory to and during the hospital visit. One hundred children aged 5–15 (50 children during the preinterventional data collection and 50 children postinterventionally) reported pain intensity and distress during needle-related procedures in nitrous oxide sedation. The results showed that the intervention had a positive effect in significantly lowering the level of preprocedural distress. The results showed that the pain intensity was also lowered however not reaching statistical significance. This confirms other positive research results on the use of visual supports within paediatric care, a topic that has to be further studied.
Mindfulness-Based Intervention for Adolescents with Recurrent Headaches: A Pilot Feasibility Study
Authors: Hesse Toni , Holmes Laura G. , Kennedy-Overfelt Vicki , Kerr Lynne M. , Giles Lisa L.
Published: December 2015

Recurrent headaches cause significant burden for adolescents and their families. Mindfulness-based interventions (MBIs) have been shown to reduce stress and alter the experience of pain, reduce pain burden, and improve quality of life. Research indicates that MBIs can benefit adults with chronic pain conditions including headaches. A pilot nonrandomized clinical trial was conducted with 20 adolescent females with recurrent headaches. Median class attendance was 7 of 8 total sessions; average class attendance was6.10±2.6. Adherence to home practice was good, with participants reporting an average of 4.69 (SD = 1.84) of 6 practices per week. Five participants dropped out for reasons not inherent to the group (e.g., extracurricular scheduling); no adverse events were reported. Parents reported improved quality of life and physical functioning for their child. Adolescent participants reported improved depression symptoms and improved ability to accept their pain rather than trying to control it. MBIs appear safe and feasible for adolescents with recurrent headaches. Although participants did not report decreased frequency or severity of headache following treatment, the treatment had a beneficial effect for depression, quality of life, and acceptance of pain and represents a promising adjunct treatment for adolescents with recurrent headaches.
Prevalence and Predictors of Thyroid Dysfunction in Patients with HIV Infection and Acquired Immunodeficiency Syndrome: An Indian Perspective
Authors: Sharma Neera , Sharma Lokesh Kumar , Dutta Deep , Gadpayle Adesh Kisanji , Anand Atul , Gaurav Kumar , Mukherjee Sabyasachi , Bansal Rahul
Published: December 2015

Background. Predictors of thyroid dysfunction in HIV are not well determined. This study aimed to determine the prevalence and predictors of thyroid dysfunction in HIV infected Indians.Methods. Consecutive HIV patients, 18–70 years of age, without any severe comorbid state, having at least 1-year follow-up at the antiretroviral therapy clinic, underwent clinical assessment and hormone assays.Results. From initially screened 527 patients, 359 patients (61.44±39.42months’ disease duration), having good immune function [CD4 count >200 cell/mm3: 90.25%; highly active antiretroviral therapy (HAART): 88.58%], were analyzed. Subclinical hypothyroidism (ScH) was the commonest thyroid dysfunction (14.76%) followed by sick euthyroid syndrome (SES) (5.29%) and isolated low TSH (3.1%). Anti-TPO antibody (TPOAb) was positive in 3.90%. Baseline CD4 count had inverse correlation with TPOAb after adjusting for age and body mass index. Stepwise linear regression revealed baseline CD4 count, TPOAb, and tuberculosis to be best predictors of ScH after adjusting for age, weight, duration of HIV, and history of opportunistic fungal and viral infections.Conclusion. Burden of thyroid dysfunction in chronic HIV infection with stable immune function is lower compared to pre-HAART era. Thyroid dysfunction is primarily of nonautoimmune origin, predominantly ScH. Severe immunodeficiency at disease onset, TPOAb positivity, and tuberculosis were best predictors of ScH.
Boundedness of Commutators of Marcinkiewicz Integrals on Nonhomogeneous Metric Measure Spaces
Authors: Lu Guanghui , Tao Shuangping
Published: December 2015

Let(X,d,μ)be a metric measure space satisfying the upper doubling condition and geometrically doubling condition in the sense of Hytönen. The aim of this paper is to establish the boundedness of commutatorMbgenerated by the Marcinkiewicz integralMand Lipschitz functionb. The authors prove thatMbis bounded from the Lebesgue spacesLp(μ)to weak Lebesgue spacesLq(μ)for1≤p<n/β, from the Lebesgue spacesLp(μ)to the spacesRBMO(μ)forp=n/β, and from the Lebesgue spacesLp(μ)to the Lipschitz spacesLip(β-n/p)(μ)forn/β<p≤∞. Moreover, some results in Morrey spaces and Hardy spaces are also discussed.
Operational Efficiency Forecasting Model of an Existing Underground Mine Using Grey System Theory and Stochastic Diffusion Processes
Authors: Strbac Savic Svetlana , Nedeljkovic Ostojic Jasmina , Gligoric Zoran , Cvijovic Cedomir , Aleksandrovic Snezana
Published: December 2015

Forecasting the operational efficiency of an existing underground mine plays an important role in strategic planning of production. Degree of Operating Leverage (DOL) is used to express the operational efficiency of production. The forecasting model should be able to involve common time horizon, taking the characteristics of the input variables that directly affect the value of DOL. Changes in the magnitude of any input variable change the value of DOL. To establish the relationship describing the way of changing we applied multivariable grey modeling. Established time sequence multivariable response formula is also used to forecast the future values of operating leverage. Operational efficiency of production is often associated with diverse sources of uncertainties. Incorporation of these uncertainties into multivariable forecasting model enables mining company to survive in today’s competitive environment. Simulation of mean reversion process and geometric Brownian motion is used to describe the stochastic diffusion nature of metal price, as a key element of revenues, and production costs, respectively. By simulating a forecasting model, we imitate its action in order to measure its response to different inputs. The final result of simulation process is the expected value of DOL for every year of defined time horizon.
Image Segmentation by Edge Partitioning over a Nonsubmodular Markov Random Field
Authors: Jung Ho Yub , Lee Kyoung Mu
Published: December 2015

Edge weight-based segmentation methods, such as normalized cut or minimum cut, require a partition number specification for their energy formulation. The number of partitions plays an important role in the segmentation overall quality. However, finding a suitable partition number is a nontrivial problem, and the numbers are ordinarily manually assigned. This is an aspect of the general partition problem, where finding the partition number is an important and difficult issue. In this paper, the edge weights instead of the pixels are partitioned to segment the images. By partitioning the edge weights into two disjoints sets, that is, cut and connect, an image can be partitioned into all possible disjointed segments. The proposed energy function is independent of the number of segments. The energy is minimized by iterating the QPBO-α-expansion algorithm over the pairwise Markov random field and the mean estimation of the cut and connected edges. Experiments using the Berkeley database show that the proposed segmentation method can obtain equivalently accurate segmentation results without designating the segmentation numbers.
New Approaches for Solving Fokker Planck Equation on Cantor Sets within Local Fractional Operators
Authors: Jassim Hassan Kamil
Published: December 2015

We discuss new approaches to handling Fokker Planck equation on Cantor sets within local fractional operators by using the local fractional Laplace decomposition and Laplace variational iteration methods based on the local fractional calculus. The new approaches maintain the efficiency and accuracy of the analytical methods for solving local fractional differential equations. Illustrative examples are given to show the accuracy and reliable results.
Assessment of Nurses’ Knowledge, Attitude, and Perceived Barriers to Expressed Pressure Ulcer Prevention Practice in Addis Ababa Government Hospitals, Addis Ababa, Ethiopia, 2015
Authors: Dilie Abebe , Mengistu Daniel
Published: December 2015

Background. Although pressure ulcer development is now generally considered as an indicator for quality of nursing care, questions and concerns about situations in which they are unavoidable remain. Awareness about the significance of the problem, positive attitude towards prevention, and an adequate level of knowledge are cornerstones to effectively prevent pressure ulcers. Objective. To assess nurses’ knowledge, attitudes, and perceived barriers to expressed pressure ulcer prevention practice in Addis Ababa government hospitals. Methods and Materials. This is a cross-sectional study by design. A total of 217 eligible nurses participated in the study and data were collected through pretested self-administered questionnaire. Results. When queried, 61.2% of the respondents had adequate knowledge on pressure ulcer prevention practices, while 68.4% had favorable attitudes towards prevention practices. Moreover, 67.3% of participants had good pressure ulcer prevention practices. Conclusion and Recommendation. More than half of the nurses were found to have adequate knowledge about pressure ulcer prevention and their attitude towards it was overall favorable. Expressed pressure ulcer prevention practice was affected by the participant’s level of knowledge, attitude, and barriers of care. To provide effective prevention of pressure ulcer, nurses’ level of knowledge and attitude should be enhanced besides resolving these barriers.
FEM Analysis of Mandibular Prosthetic Overdenture Supported by Dental Implants: Evaluation of Different Retention Methods
Authors: Cicciù M. , Cervino G. , Bramanti E. , Lauritano F. , Lo Gudice G. , Scappaticci L. , Rapparini A. , Guglielmino E. , Risitano G.
Published: December 2015

Prosthetic rehabilitation of total edentulous jaws patients is today a common technique that clinicians approach in their daily practice. The use of dental implants for replacing missing teeth is going to be a safe technique and the implant-prosthetic materials give the possibility of having long-term clinical success. Aim of this work is to evaluate the mechanical features of three different prosthetic retention systems. By applying engineering systems of investigations like FEM and von Mises analyses, how the dental implant material holds out against the masticatory strength during the chewing cycles has been investigated. Three common dental implant overdenture retention systems have been investigated. The ball attachment system, the locator system, and the common dental abutment have been processed by Ansys Workbench 15.0 and underwent FEM and von Mises investigations. The elastic features of the materials used in the study have been taken from recent literature data. Results revealed different response for both types of device, although locator system showed better results for all conditions of loading. The data of this virtual model show all the features of different prosthetic retention systems under the masticatory load. Clinicians should find the better prosthetic solution related to the patients clinical condition in order to obtain long-term results.