bluuebunny/crossref_metadata_2025 huggingface dataset:
Combined laparoscopic-assisted nephrectomy and complete mesocolic excision for synchronous renal and colon cancers
Authors: O'Sullivan M , Kearney D E , Giri S K , Coffey J C
Published: September 2015

Cancers of the colon and kidney are common malignancies, however, the occurrence of primary synchronous neoplasms of these two organs is uncommon. To the best of our knowledge, this is the first case report of a laparoscopic radical left nephrectomy and extended right complete mesocolic excision (CME) for a patient with synchronous renal and colon cancers. While a radical nephrectomy has long been the standard of care for a renal malignancy, CME has only recently been used. Combined surgeries provide the patient with various benefits such as decreased hospital stay, less postoperative pain and morbidity, early return to work and better cosmoses.
Osteoblastoma of the coracoid process: an unusual location
Authors: Arockiaraj Justin , Balaji G Gopisankar , Vidyasagar Bandikala , Ashok Anand
Published: September 2015

Bone tumours arising from the coracoid process of the scapula are very rare. We present a case of a 19-year-old man with left shoulder pain for 1 year, with associated infraclavicular swelling for 8 months. Examination revealed a tender, bony, hard swelling measuring 3×4 cm. Imaging revealed an expansile osteolytic lesion arising from the coracoid process with loss of corticomedullary differentiation. MRI showed altered signal in the adjacent soft tissues. The patient underwent en bloc resection of the lesion. Histology was suggestive of osteoblastoma. At the end of 2 years follow-up, the patient had no pain or recurrence of the lesion. We present this case for its rare location and have briefly discussed the difficulties in diagnosis of this condition.
Unusual diagnosis of a solitary thyroid nodule in the paediatric population: cervical thymic cyst
Authors: Sadacharan Dhalapathy , Sathya Anjali , Ravikumar Divya , Nallapa Deepakala
Published: September 2015

We present a case of an 8-year-old girl with a painless swelling in her neck. An ultrasonogram revealed a cystic nodule with internal echoes, lying posterior to right lobe of thyroid, and MRI confirmed it. Thyroid scintigraphy did not show any uptake in the swelling. Intraoperatively, the lesion was densely adherent to the thyroid gland, hence a hemithyroidectomy was performed. Histopathology showed it to be an ectopic cervical thymic cyst with parathyroid tissue.
A systematic review of reliable and valid tools for the measurement of patient participation in healthcare
Authors: Phillips Nicole Margaret , Street Maryann , Haesler Emily
Published: September 2015

Introduction

Patient participation in healthcare is recognised internationally as essential for consumer-centric, high-quality healthcare delivery. Its measurement as part of continuous quality improvement requires development of agreed standards and measurable indicators.

Aim

This systematic review sought to identify strategies to measure patient participation in healthcare and to report their reliability and validity. In the context of this review, patient participation was constructed as shared decision-making, acknowledging the patient as having critical knowledge regarding their own health and care needs and promoting self-care/autonomy.

Methods

Following a comprehensive search, studies reporting reliability or validity of an instrument used in a healthcare setting to measure patient participation, published in English between January 2004 and March 2014 were eligible for inclusion.

Results

From an initial search, which identified 1582 studies, 156 studies were retrieved and screened against inclusion criteria. Thirty-three studies reporting 24 patient participation measurement tools met inclusion criteria, and were critically appraised. The majority of studies were descriptive psychometric studies using prospective, cross-sectional designs. Almost all the tools completed by patients, family caregivers, observers or more than one stakeholder focused on aspects of patient–professional communication. Few tools designed for completion by patients or family caregivers provided valid and reliable measures of patient participation. There was low correlation between many of the tools and other measures of patient satisfaction.

Conclusion

Few reliable and valid tools for measurement of patient participation in healthcare have been recently developed. Of those reported in this review, the dyadic Observing Patient Involvement in Decision Making (dyadic-OPTION) tool presents the most promise for measuring core components of patient participation. There remains a need for further study into valid, reliable and feasible strategies for measuring patient participation as part of continuous quality improvement.
Blood pressure response to exercise in young athletes aged 10 to 18 years
Authors: Szmigielska Katarzyna , Szmigielska-Kapłon Anna , Jegier Anna
Published: September 2015

The aim of the study was to determine arterial blood pressure response to exercise in young athletes. The study group comprised 711 young athletes (457 boys, 254 girls) aged 10 to 18 years (mean 13.41 ± 3.12 years) who had been training for an average of 7.62 ± 4.2 h per week for an average of 4.01 ± 2.5 years. Participants with elevated arterial blood pressure above the 90th percentile at rest were excluded from investigation. A symptom-limited, multistage exercise test to exhaustion was performed using a Monark cycle ergometer. Arterial blood pressure was measured with an aneroid manometer in the third minute of each stage of the test. Mean systolic arterial blood pressure during peak exercise was significantly higher in boys than in girls: 183.21 ± 27.97 mm Hg and 170.97 ± 21.4 mm Hg, respectively (p = 0.03). Multivariate linear regression analysis showed that age and workload had significant effects on arterial blood pressure during the test. Systolic arterial blood pressure during the exercise can be described with the following equations: boys, SBPex (mm Hg) = –1.92 × age (years) + 0.55 × workload (W) + 120.84; girls, SBPex (mm Hg) = –0.88 × age (years) + 0.48 × workload (W) + 111.22. The study results describe reference values of arterial blood pressure during the exercise test. The presented equations and figures can help to assess whether the arterial blood pressure at each stage of the exercise test exceeds the normal range or not.
The gauge sector of the SME with Lorentz-symmetry violation by symplectic projector method
Authors: Belich H. , Santos M. A. , Orlando M. T. D.
Published: September 2015

We propose to analyze a modified electromagnetism inspired from the gauge sector of the Standard Model extension (SME). From the point of view of a canonical formulation, we carried out the usual analysis on the constraints structure of the odd sector (Carroll–Field–Jackiw term) and a Maxwell term with an effective metric. This effective metric is obtained by a vectorial decomposition of the CPT-even term, that is absorbed in the ordinary Maxwell term. Using symplectic projector method (SPM), we obtain the dispersions relations and we have verified conditions of stability to determine the valid spectrum.
Green’s functions for translation invariant star products
Authors: Lizzi Fedele , Rivera Manolo , Vitale Patrizia
Published: September 2015

We calculate the Green’s functions for a scalar field theory with quartic interactions for which the fields are multiplied with a generic translation invariant star product. Our analysis involves both non-commutative products, for which there is the canonical commutation relation among coordinates, and nonlocal commutative products. We give explicit expressions for the one-loop corrections to the two- and four-point functions. We find that the phenomenon of ultraviolet/infrared mixing is always a consequence of the presence of non-commuting variables. The commutative part of the product does not have the mixing.
A Method for Constructing Bijective S-Box with High Nonlinearity Based on Chaos and Optimization
Authors: Wang Yong , Lei Peng , Wong Kwok-Wo
Published: September 2015

Although chaotic maps possess useful properties, such as being highly nonlinear and pseudorandom, for designing S-box, the cryptographic performance of the chaos-based substitution box (S-box) cannot achieve a very high level, especially in nonlinearity. In this paper, two conditions of improving the nonlinearity of S-box are firstly given according to the process of calculating nonlinearity. A novel method combining chaos and optimization operations is proposed for constructing S-box with high nonlinearity. There are three phases in our method. In the first phase, the S-box is initialized by a chaotic map. Then, its nonlinearity is enhanced by an optimization method in the second phase. To avoid the result of falling into local optima, some adjustments are done in the final phase. Experimental results show that the S-boxes constructed by the proposed method have a much higher nonlinearity than those only based on chaotic maps. This justifies that our algorithm is effective in generating S-boxes with high cryptographic performance.
Hopf Bifurcation in Two Groups of Delay-Coupled Kuramoto Oscillators
Authors: Guo Yuxiao , Jiang Weihua
Published: September 2015

Hopf bifurcation in two groups of Kuramoto's phase oscillators with delay-coupled interactions is investigated on the Ott–Antonsen's manifold. We find that the reduced delay differential system undergoes Hopf bifurcations when the coupling strength between two groups exceeds some critical values. With the increasing of time delay, stability switches are observed which leads to the synchrony switches for the Kuramoto system. The direction of Hopf bifurcation and the stability of bifurcating periodic solutions are investigated by deriving the normal forms on the center manifold. With respect to the Kuramoto system, simulations are performed to support our analytic results.
Bounds of the Chaotic System for Couette–Taylor Flow and Its Application in Finite-Time Control
Authors: Zahedi Moosarreza Shamsyeh , Saberi Nik Hassan
Published: September 2015

In this paper, the boundedness of solutions of the chaotic system for the incompressible flow between two concentric rotating cylinders, known as Couette–Taylor flow, has been studied. Based on Lagrange multiplier method and generalized positive definite and radially unbound Lyapunov functions with respect to the parameters of the system, we derive the ultimate bound and the globally exponentially attractive set for this system. Then, the result is applied to the finite-time stabilization. Moreover, numerical simulations are presented to show the effectiveness of the method.
Center Problems and Limit Cycle Bifurcations in a Class of Quasi-Homogeneous Systems
Authors: Xiong Yanqin , Han Maoan , Wang Yong
Published: September 2015

In this paper, we first classify all centers of a class of quasi-homogeneous polynomial differential systems of degree 5. Then we extend this kind of systems to a generalized polynomial differential system and provide the necessary and sufficient conditions to have a center at the origin. Furthermore, we study the Poincaré bifurcation for its perturbed system as it has a center at the origin, find the Poincaré cyclicity up to first order of ε.
Evaluating Process Parameters of Multi-Pass Turning Process Using Hybrid Genetic Simulated Swarm Algorithm
Authors: Gayatri R. , Baskar N.
Published: September 2015

Evolutionary computation is one of the important problems solving method frequently used by the researchers. The choice of an algorithm to optimize the problem is determined by some sort of reliability of the researcher with that technique. To overcome the limitations in individual algorithms and to achieve synergic effects, fusion or hybridization of two or more algorithms is carried out. Hybrid algorithms have gained popularity because there is no evidence that a universal optimal strategy exists for solving optimization problems. In this work, a hybrid algorithm called hybrid genetic simulated swarm (HGSS) algorithm is proposed to optimize the parameters of multi-pass turning operation. The HGSS algorithm is a fusion of genetic algorithm (GA), simulated annealing (SA) and particle swarm optimization (PSO) algorithms. The objectives of this work are (i) to explore and exploit the problem search space through hybridization, (ii) to justify that proficient hybridization of evolutionary algorithms (EAs) will yield an efficient means to solve the optimization problems. In this work, the EAs such as GA, SA and PSO are also applied to optimize parameters and results are compared with HGSS. The results of the proposed work HGSS are very effective than other algorithms.
Learning to Rank from Noisy Data
Authors: Ding Wenkui , Geng Xiubo , Zhang Xu-Dong
Published: September 2015

Learning to rank, which learns the ranking function from training data, has become an emerging research area in information retrieval and machine learning. Most existing work on learning to rank assumes that the training data is clean, which is not always true, however. The ambiguity of query intent, the lack of domain knowledge, and the vague definition of relevance levels all make it difficult for common annotators to give reliable relevance labels to some documents. As a result, the relevance labels in the training data of learning to rank usually contain noise. If we ignore this fact, the performance of learning-to-rank algorithms will be damaged.

In this article, we propose considering the labeling noise in the process of learning to rank and using a two-step approach to extend existing algorithms to handle noisy training data. In the first step, we estimate the degree of labeling noise for a training document. To this end, we assume that the majority of the relevance labels in the training data are reliable and we use a graphical model to describe the generative process of a training query, the feature vectors of its associated documents, and the relevance labels of these documents. The parameters in the graphical model are learned by means of maximum likelihood estimation. Then the conditional probability of the relevance label given the feature vector of a document is computed. If the probability is large, we regard the degree of labeling noise for this document as small; otherwise, we regard the degree as large. In the second step, we extend existing learning-to-rank algorithms by incorporating the estimated degree of labeling noise into their loss functions. Specifically, we give larger weights to those training documents with smaller degrees of labeling noise and smaller weights to those with larger degrees of labeling noise. As examples, we demonstrate the extensions for McRank, RankSVM, RankBoost, and RankNet. Empirical results on benchmark datasets show that the proposed approach can effectively distinguish noisy documents from clean ones, and the extended learning-to-rank algorithms can achieve better performances than baselines.
Life after MOOCs
Authors: Compeau Phillip , Pevzner Pavel A.
Published: September 2015

Online science education needs a new revolution.
Seeking anonymity in an internet panopticon
Authors: Feigenbaum Joan , Ford Bryan
Published: September 2015

The Dissent system aims for a quantifiably secure, collective approach to anonymous communication online.
Constructing Large and Fast On-Chip Cache for Mobile Processors with Multilevel Cell STT-MRAM Technology
Authors: Jiang Lei , Zhao Bo , Yang Jun , Zhang Youtao
Published: September 2015

Modern mobile processors integrating an increasing number of cores into one single chip demand large-capacity, on-chip, last-level caches (LLCs) in order to achieve scalable performance improvements. However, adopting traditional memory technologies such as SRAM and embedded DRAM (eDRAM) leakage and scalability problems. Spin-transfer torque magnetic RAM (STT-MRAM) is a novel nonvolatile memory technology that has emerged as a promising alternative for constructing on-chip caches in high-end mobile processors. STT-MRAM has many advantages, such as short read latency, zero leakage from the memory cell, and better scalability than eDRAM and SRAM. Multilevel cell (MLC) STT-MRAM further enlarges capacity and reduces per-bit cost by storing more bits in one cell.

However, MLC STT-MRAM has long write latency which limits the effectiveness of MLC STT-MRAM-based LLCs. In this article, we address this limitation with three novel designs: line pairing (LP), line swapping (LS), and dynamic LP/LS enabler (DLE). LP forms fast cache lines by reorganizing MLC soft bits which are faster to write. LS dynamically stores frequently-written data into these fast cache lines. We then propose a dynamic LP/LS enabler (DLE) to enable LP and LS only if they help to improve the overall cache performance. Our experimental results show that the proposed designs improve system performance by 9--15% and reduce energy consumption by 14--21% for various types of mobile processors.
Use It or Lose It
Authors: Kim Hyungjun , Boga Siva Bhanu Krishna , Vitkovskiy Arseniy , Hadjitheophanous Stavros , Gratz Paul V. , Soteriou Vassos , Michael Maria K.
Published: September 2015

Moore's Law scaling continues to yield higher transistor density with each succeeding process generation, leading to today's many-core chip multiprocessors (CMPs) with tens or even hundreds of interconnected cores or tiles. Unfortunately, deep submicron CMOS process technology is marred by increasing susceptibility to wear. Prolonged operational stress gives rise to accelerated wearout and failure due to several physical failure mechanisms, including hot-carrier injection (HCI) and negative-bias temperature instability (NBTI). Each failure mechanism correlates with different usage-based stresses, all of which can eventually generate permanent faults. While the wearout of an individual core in many-core CMPs may not necessarily be catastrophic, a single fault in the interprocessor network-on-chip (NoC) fabric could render the entire chip useless, as it could lead to protocol-level deadlocks, or even partition away vital components such as the memory controller or other critical I/O. In this article, we study HCI- and NBTI-induced wear due to actual stresses caused by real workloads, applied onto the interconnect microarchitecture and develop a critical path model for NBTI-induced wearout. A key finding of this modeling is that, counter to prevailing wisdom, wearout in the CMP's on-chip interconnect is correlated with lack of load observed in the NoC routers rather than high load. We then develop a novel wearout-decelerating scheme in which routers under low load have their wear-sensitive components exercised without significantly impacting cycle time, pipeline depth, area, or power consumption of the overall router. A novel deterministic approach is proposed for the generation of appropriate exercise-mode data, ensuring design parameter targets are met. We subsequently show that the proposed design yields an ∼2,300× decrease in the rate of wear.
Many-Objective Evolutionary Algorithms
Authors: Li Bingdong , Li Jinlong , Tang Ke , Yao Xin
Published: September 2015

Multiobjective evolutionary algorithms (MOEAs) have been widely used in real-world applications. However, most MOEAs based on Pareto-dominance handle many-objective problems (MaOPs) poorly due to a high proportion of incomparable and thus mutually nondominated solutions. Recently, a number of many-objective evolutionary algorithms (MaOEAs) have been proposed to deal with this scalability issue. In this article, a survey of MaOEAs is reported. According to the key ideas used, MaOEAs are categorized into seven classes: relaxed dominance based, diversity-based, aggregation-based, indicator-based, reference set based, preference-based, and dimensionality reduction approaches. Several future research directions in this field are also discussed.
Location-Free Detection of Network Boundaries
Authors: Schieferdecker Dennis
Published: September 2015

A novel algorithm is proposed for the distributed and location-free detection of boundaries in sensor networks. The approach allows a node to decide autonomously, based solely on connectivity information of a small 2-hop neighborhood, whether it is in the interior of the network or on its fringes. This makes the presented algorithm well suited for scenarios that include mobility or dynamic changes to the network topology.

The algorithm is compared qualitatively and quantitatively to multiple previous approaches. Various models and network settings are considered in extensive simulations. Even though the algorithm uses less information than most other approaches, it yields significantly better results. It is very robust against variations in node degree and does not rely on simplified assumptions of the communication model. Moreover, the approach is easy to implement on real sensor nodes, as it requires little computational power.
Verifying Linearisability
Authors: Dongol Brijesh , Derrick John
Published: September 2015

Linearisability is a key correctness criterion for concurrent data structures, ensuring that each history of the concurrent object under consideration is consistent with respect to a history of the corresponding abstract data structure. Linearisability allows concurrent (i.e., overlapping) operation calls to take effect in any order, but requires the real-time order of nonoverlapping to be preserved. The sophisticated nature of concurrent objects means that linearisability is difficult to judge, and hence, over the years, numerous techniques for verifying lineasizability have been developed using a variety of formal foundations such as data refinement, shape analysis, reduction, etc. However, because the underlying framework, nomenclature, and terminology for each method is different, it has become difficult for practitioners to evaluate the differences between each approach, and hence, evaluate the methodology most appropriate for verifying the data structure at hand. In this article, we compare the major of methods for verifying linearisability, describe the main contribution of each method, and compare their advantages and limitations.
RT @News
Authors: Bhattacharya Devipsita , Ram Sudha
Published: September 2015

News agencies regularly use Twitter to publicize and increase readership of their articles. Although substantial research on the spread of news on Twitter exists, there hasn't been much focus on the study of the spread of news articles. In this study, we present an innovative methodology involving weighted ego networks to understand how news agencies propagate news articles using their Twitter handle. We propose a set of measures to compare the propagation process of different news agencies by studying important aspects such as volume, extent of spread, conversion rate, multiplier effect, lifespan, hourly response, and audience participation. Using a dataset of tweets collected over a period of 6 months, we apply our methodology and suggest a framework to help news agencies gauge their performance on social media and also provide critical insights into the phenomenon of news article propagation on Twitter.
The morality of online war; the fates of data analytics, HPC
Authors: Arquilla John , Reed Daniel A.
Published: September 2015

The
Communications
Web site, http://cacm.acm.org, features more than a dozen bloggers in the BLOG@CACM community. In each issue of
Communications
, we will publish selected posts or excerpts.

twitter

Follow us on Twitter at http://twitter.com/blogCACM

http://cacm.acm.org/blogs/blog-cacm

John Arquilla considers justifications for warfare in the cyber realm, while Daniel Reed looks ahead at big data and exascale computing.
A Systematic Survey of Online Data Mining Technology Intended for Law Enforcement
Authors: Edwards Matthew , Rashid Awais , Rayson Paul
Published: September 2015

As an increasing amount of crime takes on a digital aspect, law enforcement bodies must tackle an online environment generating huge volumes of data. With manual inspections becoming increasingly infeasible, law enforcement bodies are optimising online investigations through data-mining technologies. Such technologies must be well designed and rigorously grounded, yet no survey of the online data-mining literature exists which examines their techniques, applications and rigour. This article remedies this gap through a systematic mapping study describing online data-mining literature which visibly targets law enforcement applications, using evidence-based practices in survey making to produce a replicable analysis which can be methodologically examined for deficiencies.
Fona
Authors: Watanabe Willian Massami , Dias Ana Luiza , Fortes Renata Pontin De Mattos
Published: September 2015

The Web 2.0 brought new requirements to the architecture of web systems. Web applications’ interfaces are becoming more and more interactive. However, these changes are severely impacting how disabled users interact through assistive technologies with the web. In order to deploy an accessible web application, developers can use WAI-ARIA to design an accessible web application, which manually implements focus and keyboard navigation mechanisms. This article presents a quantitative metric, named Fona, which measures how the Focus Navigation WAI-ARIA requirement has been implemented on the web. Fona counts JavaScript mouse event listeners, HTML elements with role attributes, and TabIndex attributes in the DOM structure of webpages. Fona’s evaluation approach provides a narrow analysis of one single accessibility requirement. But it enables monitoring this accessibility requirement in a large number of webpages. This monitoring activity might be used to give insights about how Focus Navigation and ARIA requirements have been considered by web development teams. Fona is validated comparing the results of a set of WAI-ARIA conformant implementations and a set of webpages formed by Alexa’s 349 top most popular websites. The analysis of Fona’s value for Alexa’s websites highlights that many websites still lack the implementation of Focus Navigation through their JavaScript interactive content.
Looking Backward to Look Forward
Authors: Tenenberg Josh , McCartney Robert
Published: September 2015

This editorial marks the end of our tenure as founding co-editors-in-chief of the ACM
Transactions on Computing Education
(TOCE). We have three goals in this editorial. First, we provide a retrospective on how we positioned TOCE, both in terms of how it embodies our conception of Computing Education Research (CER) as a field, as well as the journal's role in the larger computing education community and the ACM. We focus on the process by which we determined what constitutes publishability for a manuscript submitted to TOCE, describing what is best understood as a living process negotiated among the authors, reviewers, associate editors, and editors-in-chief in interaction with manuscripts and one another. Second, having reviewed a bit of history, we look at some possible changes in TOCE's future, particularly in light of conversations that the ACM is engaged in at all levels regarding recent open publishing initiatives as well as the relationship between journal and conference publications. Finally, we thank the many people who have contributed to the success of TOCE for their significant effort in establishing TOCE as a publication venue for papers in computing education.
How to Bid the Cloud
Authors: Zheng Liang , Joe-Wong Carlee , Tan Chee Wei , Chiang Mung , Wang Xinyu
Published: September 2015

Amazon's Elastic Compute Cloud (EC2) uses auction-based spot pricing to sell spare capacity, allowing users to bid for cloud resources at a highly reduced rate. Amazon sets the spot price dynamically and accepts user bids above this price. Jobs with lower bids (including those already running) are interrupted and must wait for a lower spot price before resuming. Spot pricing thus raises two basic questions: how might the provider set the price, and what prices should users bid? Computing users' bidding strategies is particularly challenging: higher bid prices reduce the probability of, and thus extra time to recover from, interruptions, but may increase users' cost. We address these questions in three steps: (1) modeling the cloud provider's setting of the spot price and matching the model to historically offered prices, (2) deriving optimal bidding strategies for different job requirements and interruption overheads, and (3) adapting these strategies to MapReduce jobs with master and slave nodes having different interruption overheads. We run our strategies on EC2 for a variety of job sizes and instance types, showing that spot pricing reduces user cost by 90% with a modest increase in completion time compared to on-demand pricing.
Silo
Authors: Jang Keon , Sherry Justine , Ballani Hitesh , Moncaster Toby
Published: September 2015

Many cloud applications can benefit from guaranteed latency for their network messages, however providing such predictability is hard, especially in multi-tenant datacenters. We identify three key requirements for such predictability: guaranteed network bandwidth, guaranteed packet delay and guaranteed burst allowance. We present Silo, a system that offers these guarantees in multi-tenant datacenters. Silo leverages the tight coupling between bandwidth and delay: controlling tenant bandwidth leads to deterministic bounds on network queuing delay. Silo builds upon network calculus to place tenant VMs with competing requirements such that they can coexist. A novel hypervisor-based policing mechanism achieves packet pacing at sub-microsecond granularity, ensuring tenants do not exceed their allowances. We have implemented a Silo prototype comprising a VM placement manager and a Windows filter driver. Silo does not require any changes to applications, guest OSes or network switches. We show that Silo can ensure predictable message latency for cloud applications while imposing low overhead.
Congestion Control for Large-Scale RDMA Deployments
Authors: Zhu Yibo , Eran Haggai , Firestone Daniel , Guo Chuanxiong , Lipshteyn Marina , Liron Yehonatan , Padhye Jitendra , Raindel Shachar , Yahia Mohamad Haj , Zhang Ming
Published: September 2015

Modern datacenter applications demand high throughput (40Gbps) and ultra-low latency (< 10 μs per hop) from the network, with low CPU overhead. Standard TCP/IP stacks cannot meet these requirements, but Remote Direct Memory Access (RDMA) can. On IP-routed datacenter networks, RDMA is deployed using RoCEv2 protocol, which relies on Priority-based Flow Control (PFC) to enable a drop-free network. However, PFC can lead to poor application performance due to problems like head-of-line blocking and unfairness. To alleviates these problems, we introduce DCQCN, an end-to-end congestion control scheme for RoCEv2. To optimize DCQCN performance, we build a fluid model, and provide guidelines for tuning switch buffer thresholds, and other protocol parameters. Using a 3-tier Clos network testbed, we show that DCQCN dramatically improves throughput and fairness of RoCEv2 RDMA traffic. DCQCN is implemented in Mellanox NICs, and is being deployed in Microsoft's datacenters.
SpotFi
Authors: Kotaru Manikanta , Joshi Kiran , Bharadia Dinesh , Katti Sachin
Published: September 2015

This paper presents the design and implementation of SpotFi, an accurate indoor localization system that can be deployed on commodity WiFi infrastructure. SpotFi only uses information that is already exposed by WiFi chips and does not require any hardware or firmware changes, yet achieves the same accuracy as state-of-the-art localization systems. SpotFi makes two key technical contributions. First, SpotFi incorporates super-resolution algorithms that can accurately compute the angle of arrival (AoA) of multipath components even when the access point (AP) has only three antennas. Second, it incorporates novel filtering and estimation techniques to identify AoA of direct path between the localization target and AP by assigning values for each path depending on how likely the particular path is the direct path. Our experiments in a multipath rich indoor environment show that SpotFi achieves a median accuracy of 40 cm and is robust to indoor hindrances such as obstacles and multipath.
A Declarative and Expressive Approach to Control Forwarding Paths in Carrier-Grade Networks
Authors: Hartert Renaud , Vissicchio Stefano , Schaus Pierre , Bonaventure Olivier , Filsfils Clarence , Telkamp Thomas , Francois Pierre
Published: September 2015

SDN simplifies network management by relying on declarativity (high-level interface) and expressiveness (network flexibility). We propose a solution to support those features while preserving high robustness and scalability as needed in carrier-grade networks. Our solution is based on (i) a two-layer architecture separating connectivity and optimization tasks; and (ii) a centralized optimizer called framework, which translates high-level goals expressed almost in natural language into compliant network configurations. Our evaluation on real and synthetic topologies shows that framework improves the state of the art by (i) achieving better trade-offs for classic goals covered by previous works, (ii) supporting a larger set of goals (refined traffic engineering and service chaining), and (iii) optimizing large ISP networks in few seconds. We also quantify the gains of our implementation, running Segment Routing on top of IS-IS, over possible alternatives (RSVP-TE and OpenFlow).
Pingmesh
Authors: Guo Chuanxiong , Yuan Lihua , Xiang Dong , Dang Yingnong , Huang Ray , Maltz Dave , Liu Zhaoyi , Wang Vin , Pang Bin , Chen Hua , Lin Zhi-Wei , Kurien Varugis
Published: September 2015

Can we get network latency between any two servers at any time in large-scale data center networks? The collected latency data can then be used to address a series of challenges: telling if an application perceived latency issue is caused by the network or not, defining and tracking network service level agreement (SLA), and automatic network troubleshooting. We have developed the Pingmesh system for large-scale data center network latency measurement and analysis to answer the above question affirmatively. Pingmesh has been running in Microsoft data centers for more than four years, and it collects tens of terabytes of latency data per day. Pingmesh is widely used by not only network software developers and engineers, but also application and service developers and operators.
End-User Mapping
Authors: Chen Fangfei , Sitaraman Ramesh K. , Torres Marcelo
Published: September 2015

Content Delivery Networks (CDNs) deliver much of the world's web, video, and application content on the Internet today. A key component of a CDN is the mapping system that uses the DNS protocol to route each client's request to a ``proximal'' server that serves the requested content. While traditional mapping systems identify a client using the IP of its name server, we describe our experience in building and rolling-out a novel system called end-user mapping that identifies the client directly by using a prefix of the client's IP address. Using measurements from Akamai's production network during the roll-out, we show that end-user mapping provides significant performance benefits for clients who use public resolvers, including an eight-fold decrease in mapping distance, a two-fold decrease in RTT and content download time, and a 30% improvement in the time-to-first byte. We also quantify the scaling challenges in implementing end-user mapping such as the 8-fold increase in DNS queries. Finally, we show that a CDN with a larger number of deployment locations is likely to benefit more from end-user mapping than a CDN with a smaller number of deployments.
Scaling Up Clustered Network Appliances with ScaleBricks
Authors: Zhou Dong , Fan Bin , Lim Hyeontaek , Andersen David G. , Kaminsky Michael , Mitzenmacher Michael , Wang Ren , Singh Ajaypal
Published: September 2015

This paper presents ScaleBricks, a new design for building scalable, clustered network appliances that must "pin" flow state to a specific handling node without being able to choose which node that should be. ScaleBricks applies a new, compact lookup structure to route packets directly to the appropriate handling node, without incurring the cost of multiple hops across the internal interconnect. Its lookup structure is many times smaller than the alternative approach of fully replicating a forwarding table onto all nodes. As a result, ScaleBricks is able to improve throughput and latency while simultaneously increasing the total number of flows that can be handled by such a cluster. This architecture is effective in practice: Used to optimize packet forwarding in an existing commercial LTE-to-Internet gateway, it increases the throughput of a four-node cluster by 23%, reduces latency by up to 10%, saves memory, and stores up to 5.7x more entries in the forwarding table.
Jupiter Rising
Authors: Singh Arjun , Ong Joon , Agarwal Amit , Anderson Glen , Armistead Ashby , Bannon Roy , Boving Seb , Desai Gaurav , Felderman Bob , Germano Paulie , Kanagala Anand , Provost Jeff , Simmons Jason , Tanda Eiichi , Wanderer Jim , Hölzle Urs , Stuart Stephen , Vahdat Amin
Published: September 2015

We present our approach for overcoming the cost, operational complexity, and limited scale endemic to datacenter networks a decade ago. Three themes unify the five generations of datacenter networks detailed in this paper. First, multi-stage Clos topologies built from commodity switch silicon can support cost-effective deployment of building-scale networks. Second, much of the general, but complex, decentralized network routing and management protocols supporting arbitrary deployment scenarios were overkill for single-operator, pre-planned datacenter networks. We built a centralized control mechanism based on a global configuration pushed to all datacenter switches. Third, modular hardware design coupled with simple, robust software allowed our design to also support inter-cluster and wide-area networks. Our datacenter networks run at dozens of sites across the planet, scaling in capacity by 100x over ten years to more than 1Pbps of bisection bandwidth.
BitMiner
Authors: Yuan Zhenlong , Xue Yibo , van der Schaar Mihaela
Published: September 2015

Traditionally, signatures used for traffic classification are constructed at the byte-level. However, as more and more data-transfer formats of network protocols and applications are encoded at the bit-level, byte-level signatures are losing their effectiveness in traffic classification. In this poster, we creatively construct bit-level signatures by associating the bit-values with their bit-positions in each traffic flow. Furthermore, we present BitMiner, an automated traffic mining tool that can mine application signatures at the most fine-grained bit-level granularity. Our preliminary test on popular peer-to-peer (P2P) applications, e.g. Skype, Google Hangouts, PPTV, eMule, Xunlei and QQDownload, reveals that although they all have no byte-level signatures, there are significant bit-level signatures hidden in their traffic.
Alternative Trust Sources
Authors: Donovan Sean , Feamster Nick
Published: September 2015

DNSSEC has been in development for 20 years. It provides for provable security when retrieving domain names through the use of a public key infrastructure (PKI). Unfortunately, there is also significant overhead involved with DNSSEC: verifying certificate chains of signed DNS messages involves extra computation, queries to remote resolvers, additional transfers, and introduces added latency into the DNS query path. We pose the question: is it possible to achieve practical security without always verifying this certificate chain if we use a different, outside source of trust between resolvers? We believe we can. Namely, by using a long-lived, mutually authenticated TLS connection between pairs of DNS resolvers, we suggest that we can maintain near-equivalent levels of security with very little extra overhead compared to a non-DNSSEC enabled resolver. By using a reputation system or probabilistically verifying a portion of DNSSEC responses would allow for near-equivalent levels of security to be reached, even in the face of compromised resolvers.
FlyCast
Authors: Bao Jinzhen , Dong Dezun , Zhao Baokang , Luo Zhang , Wu Chunqing , Gong Zhenghu
Published: September 2015

In this paper, we propose FlyCast, an architecture using the physical layer of free-space optics (FSO) to accelerate multicast communication. FlyCast leverages off-the-shelf devices (e.g. switchable mirror, beam splitter) to physically split the FSO beam to multi receivers on demand, which enables to build dynamical multicast trees in physical layer and accelerates multicast communications. We demonstrate the feasibility of FlyCast through our theoretical analysis and the proof-of-concept prototype.
Could End System Caching and Cooperation Replace In-Network Caching in CCN?
Authors: Wu Haibo , Li Jun , Zhi Jiang
Published: September 2015

CCN has been witnessed as a promising future Internet architecture. In-network caching has been paid much attention, but there is still no consensus on its usage, due to its non-negligible costs. Meanwhile, massive storage and bandwidth resources of end systems still remain underutilized. To this end, we present an End System Caching and Cooperation scheme in CCN, called ESCC to realize content distribution of CCN, without using costly in-network caching. ESCC enables fast content distribution through clients caching and sharing contents with each other. Experiments show that ESCC can achieve better performance than the universal caching. It is also quite simple, efficient, robust and has low overhead. ESCC could be a candidate substitute for the costly and unnecessary universal caching.
Supercharge me
Authors: Alan Chang Michael , Holterbach Thomas , Happe Markus , Vanbever Laurent
Published: September 2015

By enabling logically-centralized and direct control of the forwarding behavior of a network, Software-Defined Networking (SDN) holds great promise in terms of improving network management, performance, and costs. Realizing this vision is challenging though as SDN proposals to date require substantial and expensive changes to the existing network architecture before the benefits can be realized. As a result, the number of SDN deployments has been rather limited in scope. To kickstart a wide-scale SDN deployment, there is a need for low-risk, high return solutions that solve a timely problem. As one possible solution, we show how we can significantly improve the performance of legacy IP routers, i.e. "supercharge" them, by combining them with SDN-enabled devices. In this abstract, we supercharge one particular aspect of the router performance: its convergence time after a link or a node failure.
Coracle
Authors: Howard Heidi , Crowcroft Jon
Published: September 2015

Distributed consensus is fundamental in distributed systems for achieving fault-tolerance. The Paxos algorithm has long dominated this domain, although it has been recently challenged by algorithms such as Raft and Viewstamped Replication Revisited. These algorithms rely on Paxos's original assumptions, unfortunately these assumptions are now at odds with the reality of the modern internet. Our insight is that current consensus algorithms have significant availability issues when deployed outside the well defined context of the datacenter. To illustrate this problem, we developed Coracle, a tool for evaluating distributed consensus algorithms in settings that more accurately represent realistic deployments. We have used Coracle to test two examples of network configurations that contradict the liveness claims of the Raft algorithm. Through the process of exercising these algorithms under more realistic assumptions, we demonstrate wider availability issues faced by consensus algorithms when deployed on real world networks.
Rule-level Data Plane Monitoring With Monocle
Authors: Perešíni Peter , Kuzniar Maciej , Kostić Dejan
Published: September 2015

We present Monocle, a system that systematically monitors the network data plane, and verifies that it corresponds to the view that the SDN controller builds and tries to enforce in the switches. Our evaluation shows that Monocle is capable of fine-grained per-rule monitoring for the majority of rules. In addition, it can help controllers to cope with switches that exhibit transient inconsistencies between their control plane and data plane states.
Santa
Authors: Schmidt Florian , Hohlfeld Oliver , Glebke René , Wehrle Klaus
Published: September 2015

Increasing network speeds challenge the packet processing performance of networked systems. This can mainly be attributed to processing overhead caused by the split between the kernel-space network stack and user-space applications. To mitigate this overhead, we propose Santa, an application agnostic kernel-level cache of frequent requests. By allowing user-space applications to offload frequent requests to the kernel-space, Santa offers drastic performance improvements and unlocks the speed of kernel-space networking for legacy server software without requiring extensive changes.
RPKI MIRO
Authors: Reuter Andreas , Wählisch Matthias , Schmidt Thomas C.
Published: September 2015

The Resource Public Key Infrastructure (RPKI) stores attestation objects for Internet resources. In this demo, we present RPKI MIRO, an open source software framework to monitor and inspect these RPKI objects. RPKI MIRO provides resource owners, RPKI operators, researchers, and lecturers with intuitive access to the content of the deployed RPKI repositories. It helps to optimize the repository structure and to identify failures.
A Mininet-based Virtual Testbed for Distributed SDN Development
Authors: Lantz Bob , O'Connor Brian
Published: September 2015

The need for fault tolerance and scalability is leading to the development of distributed SDN operating systems and applications. But how can you develop such systems and applications reliably without access to an expensive testbed? We continue to observe SDN development practices using full system virtualization or heavyweight containers, increasing complexity and overhead while decreasing usability. We demonstrate a simpler and more efficient approach: using Mininet's cluster mode to easily deploy a virtual testbed of lightweight containers on a single machine, an ad hoc cluster, or a dedicated hardware testbed. By adding an open source, distributed network operating system such as ONOS, we can create a flexible and scalable open source development platform for distributed SDN system and application software development.
Extreme Web Caching for Faster Web Browsing
Authors: Raza Ali , Zaki Yasir , Pötsch Thomas , Chen Jay , Subramanian Lakshmi
Published: September 2015

Modern web pages are very complex; each web page consists of hundreds of objects that are linked from various servers all over the world. While mechanisms such as caching reduce the overall number of end-to-end requests saving bandwidth and loading time, there is still a large portion of content that is re-fetched -- despite not having changed. In this demo, we present Extreme Cache, a web caching architecture that enhances the web browsing experience through a smart pre-fetching engine. Our extreme cache tries to predict the rate of change of web page objects to bring cacheable content closer to the user.
See How ISPs Care
Authors: Wählisch Matthias , Schmidt Thomas C.
Published: September 2015

The Resource Public Key Infrastructure (RPKI) allows BGP routers to verify the origin AS of an IP prefix. In this demo, we present a software extension which performs prefix origin validation in the web browser of end users. The browser extension shows the RPKI validation outcome of the web server infrastructure for the requested web domain. It follows the common plug-in concepts and does not require special modifications of the browser software. It operates on live data and helps end users as well as operators to gain better insight into the Internet security landscape.