bluuebunny/crossref_metadata_2025 huggingface dataset:
Distinguishing Group Privacy From Personal Privacy
Authors: Suh Jennifer Jiyoung , Metzger Miriam J. , Reid Scott A. , El Abbadi Amr
Published: November 2018

Machine learning and data mining threaten personal privacy, and many tools exist to help users protect their privacy (e.g., available privacy settings on Facebook, anonymization and encryption of personal data, etc.). But such technologies also pose threats to "group privacy," which is a concept scholars know relatively little about. Moreover, there are few tools to address the problem of protecting group privacy. This paper discusses an emerging class of software applications and services that pose new risks to group privacy by revealing group-level information based on individual information, such as social media postings or fitness app usage. The paper describes the results of two experiments that empirically establish the concept of group privacy and shows that it affects user perceptions of and interactions with information technology. The findings serve as a call to developers to design tools for group privacy protection.
Software Development and CSCW
Authors: Tendedez Helena , Ferrario Maria Angela M.A.F. , Whittle Jon
Published: November 2018

Identifying which agile methods and processes are most effective depends on the goals and aims of an organisation. Agile development promotes an environment of continuous improvement and trust within self-organising teams. Therefore, it is important to allow teams to have the flexibility to customize and tailor their chosen methods. However, in a large-scale agile deployment, there needs to be a degree of process standardization across the organisation; otherwise, different teams will not be able to effectively share knowledge and best practices. This paper addresses the classic CSCW issue of the tensions that arise between process standardization and flexibility in a large-scale agile development through a case study at the British Broadcasting Corporation (BBC).
Efficient Information Sharing Techniques between Workers of Heterogeneous Tasks in 3D CVE
Authors: Thanyadit Santawat , Punpongsanon Parinya , Pong Ting-Chuen
Published: November 2018

Collaboration between a helper and a worker in a 3D collaborative virtual environment usually requires real-time information sharing, since the worker relies on the timely assistance from the helper. In contrast, collaboration between workers requires them to shift their attention between independent tasks and dependent tasks. In worker-worker collaborations, a real-time updating technique could create excess information, which may be a distraction. In this paper, we compare different information sharing techniques and determine an efficient technique for the collaboration between workers. In our user experiment, participants performed a floor plan design task in a designer and engineer pairing on a desktop VR environment. The results showed that the proposed information sharing technique, in which objects are updated based on local users' actions, is more suitable than real-time updates. In addition, we discuss design implications that can be applied to different collaborative scenarios.
Transforming Taxonomic Interfaces
Authors: Thomer Andrea K. , Twidale Michael Bernard , Yoder Matthew J.
Published: November 2018

If scientific research can be described as "arm's length'' cooperative work, then the sciences engaged in the creation and maintenance of cooperatively built classification systems might be said to require extremely long arms; workers must reach across great distances of time, space and awareness to independently contribute to the creation and maintenance of a conceptual infrastructure. This is particularly the case for the field of biological taxonomy, in which researchers across the globe have, for more than three hundred years, cooperatively developed a massive knowledge organization system describing all life on earth. As taxonomists move from paper-based workflows to born-digital, data-first modes of publishing, new tools and approaches are needed to support their work. In this paper, we present research conducted as part of the "Transforming Taxonomic Interfaces" project aimed at improving interfaces for taxonomic software. We describe biological taxonomy in the context of CSCW, and identify key strategies taxonomists deploy to facilitate loosely coupled cooperative work. We also contribute a discussion of
semantic refactoring,
a unique kind of "articulation work'' entailed in developing, maintaining, and migrating classification systems. This work has implications for the design and study of knowledge organization systems and infrastructure, classification research, and for the development of general semantic web tools and software as well as those specifically for biological taxonomy.
Facilitating Collaboration and Social Experiences with Videogames in Dementia
Authors: Unbehaun David , Aal Konstantin , Vaziri Daryoush Daniel , Wieching Rainer , Tolmie Peter , Wulf Volker
Published: November 2018

Need for care and accordingly the prevalence of dementia is increasing rapidly. Information and communication technologies (ICT) may have the potential to support collaboration and cooperation between people with dementia and their caregivers and thus promote independency, wellbeing and quality of life of involved parties. In this context, the authors investigated the potential of an ICT-based videogame system to generate and facilitate social experiences of people with dementia and their caregivers. 26 people with dementia and their caregivers participated in a 16 month participatory design study. Results suggest that collaboration and cooperation among involved parties increased by using the system. Further, the study revealed positive and negative social experiences triggered by the videogame based system. This article will report on these results and provide implications that may support researchers to design similar systems with the potential to increase collaboration and cooperation among people with dementia and their caregivers.
'I Knew It Was Too Good to Be True"
Authors: Vitak Jessica , Liao Yuting , Subramaniam Mega , Kumar Priya
Published: November 2018

In the U.S., consumers increasingly turn to the internet and mobile apps to complete essential personal transactions, ranging from financial payments to job applications. This shift to digital transactions can create challenges for those without reliable home internet connections or with limited digital literacy by requiring them to submit sensitive information on public computers or on unfamiliar websites. Using interviews with 52 families from high-poverty communities in the mid-Atlantic region of the U.S., we explore the compounding privacy and security challenges that economically disadvantaged individuals face when navigating online services. We describe the real, perceived, and unknown risks they face as they navigate online transactions with limited technical skills, as well as the strategies and heuristics they employ to minimize these risks. The findings highlight a complex relationship between participants' negative experiences and their general mistrust of sharing data through online channels. We also describe a range of strategies participants use to try and protect their personal information. Based on these findings, we offer design recommendations to inform the creation of educational resources that we will develop in the next phase of this project.
Effect of Manipulated Amplitude and Frequency of Human Voice on Dominance and Persuasiveness in Audio Conferences
Authors: Wang Tzu-Yang , Kawaguchi Ikkaku , Kuzuoka Hideaki , Otsuki Mai
Published: November 2018

We propose to artificially manipulate participants' vocal cues, amplitude and frequency, in real time to adjust their dominance and persuasiveness during audio conferences. We implemented a prototype system and conducted two experiments. The first experiment investigated the effect of vocal cue manipulation on the perception of dominance. The results showed that participants perceived higher dominance while listening to a voice with a high amplitude and low frequency. The second experiment investigated the effect of vocal cue manipulation on persuasiveness. The results indicated that a person with a low amplitude and low frequency voice had greater persuasiveness in conversations with biased dominance, while there was no statistically significant difference in persuasiveness in conversations with unbiased dominance.
Exploring Trade-Offs Between Learning and Productivity in Crowdsourced History
Authors: Wang Nai-Ching , Hicks David , Luther Kurt
Published: November 2018

Crowdsourcing more complex and creative tasks is seen as a desirable goal for both employers and workers, but these tasks traditionally require domain expertise. Employers can recruit only expert workers, but this approach does not scale well. Alternatively, employers can decompose complex tasks into simpler micro-tasks, but some domains, such as historical analysis, cannot be easily modularized in this way. A third approach is to train workers to learn the domain expertise. This approach offers clear benefits to workers, but is perceived as costly or infeasible for employers. In this paper, we explore the trade-offs between learning and productivity in training crowd workers to analyze historical documents. We compare CrowdSCIM, a novel approach that teaches historical thinking skills to crowd workers, with two crowd learning techniques from prior work and a baseline. Our evaluation (n=360) shows that CrowdSCIM allows workers to learn domain expertise while producing work of equal or higher quality versus other conditions, but efficiency is slightly lower.
Privacy Unraveling Around Explicit HIV Status Disclosure Fields in the Online Geosocial Hookup App Grindr
Authors: Warner Mark , Gutmann Andreas , Sasse M. Angela , Blandford Ann
Published: November 2018

mHealth applications ("apps") must be searched for and downloaded prior to use, creating a potential barrier to uptake. Integrating health interventions into existing online social environments removes this barrier. However, little is known about the effects of linking sensitive health information to existing online identities. Our qualitative analysis of online comments (n=192) explores the user views of an HIV intervention integrated into the geosocial hookup app Grindr. We find some HIV positive users report keeping their status private to reduce their stigma exposure, whilst others report publicly disclosing their status to avoid being stigmatised by others. Where users keep their status private, we find concerns that social assumptions may develop around these non-disclosures, creating a privacy unraveling effect which restricts disclosure choice. Using Peppet's four proposed limits to privacy unraveling, we develop a set of descriptive conceptual designs to explore the privacy respecting potential of these limits within this context and propose further research to address this privacy challenge.
The Power of Bots
Authors: Wessel Mairieli , de Souza Bruno Mendes , Steinmacher Igor , Wiese Igor S. , Polato Ivanilton , Chaves Ana Paula , Gerosa Marco A.
Published: November 2018

Leveraging the pull request model of social coding platforms, Open Source Software (OSS) integrators review developers' contributions, checking aspects like license, code quality, and testability. Some projects use bots to automate predefined, sometimes repetitive tasks, thereby assisting integrators' and contributors' work. Our research investigates the usage and impact of such bots. We sampled 351 popular projects from GitHub and found that 93 (26%) use bots. We classified the bots, collected metrics from before and after bot adoption, and surveyed 228 developers and integrators. Our results indicate that bots perform numerous tasks. Although integrators reported that bots are useful for maintenance tasks, we did not find a consistent, statistically significant difference between before and after bot adoption across the analyzed projects in terms of number of comments, commits, changed files, and time to close pull requests. Our survey respondents deem the current bots as not smart enough and provided insights into the bots' relevance for specific tasks, challenges, and potential new features. We discuss some of the raised suggestions and challenges in light of the literature in order to help GitHub bot designers reuse and test ideas and technologies already investigated in other contexts.
Soften the Pain, Increase the Gain
Authors: Wu Y. Wayne , Bailey Brian P.
Published: November 2018

Content creators fear receiving unnecessarily harsh criticism when posting creative work in online platforms. We refer to feedback written in an unnecessary harsh tone as negative feedback. We conducted an online experiment to investigate the efficacy of three coping activities for mitigating the influence of negative feedback: self-affirmation, expressive writing, and distraction. Participants (N=480) received feedback sets with different balances of neutral and negative valence content and revised their essays after performing the assigned activity. We measured participants' affective states, extents of revision, and their perceptions of the feedback and its providers. Our results showed even a small amount of negativity had significant adverse effects on all the measures. For the coping activities, we found that expressive writing encouraged essay revision, distraction improved affective states and feedback provider perception, and self-affirmation had no significant effects on the measures. Our results contribute further empirical knowledge of how negative valence feedback impacts content creators and how the coping activities tested mitigate these effects. We also offer practical guidelines regarding when and how to use the activities tested in online feedback platforms.
Mediating Color Filter Exploration with Color Theme Semantics Derived from Social Curation Data
Authors: Wu Ziming , Sun Zhida , Kim Taewook , Reani Manuele , Jay Caroline , Ma Xiaojuan
Published: November 2018

Despite the popularity of photo editors used to improve image attractiveness and expressiveness on social media, many users have trouble making sense of color filter effects and locating a preferred filter among a set of designer-crafted candidates. The problem gets worse when more computer-generated filters are introduced. To enhance filter findability, we semantically name and organize color effects leveraging data curated by creative communities online. We first model semantic mappings between color themes and keywords in everyday language. Next, we index and organize each filter by the derived semantic information. We conduct three separate studies to investigate the benefit of the semantic features on filter exploration. Our results indicate that color theme semantics constructed through social curation enhances filter findability, providing important implications into how to use the wisdom of the crowd to improve user experience with image editors.
Understanding Motivations behind Inaccurate Check-ins
Authors: Xu Fengli , Zhang Guozhen , Chen Zhilong , Huang Jiaxin , Li Yong , Yang Diyi , Zhao Ben Y. , Meng Fanchao
Published: November 2018

Check-in data from social networks provide researchers a unique opportunity to model human dynamics at scale. However, it is unclear how indicative these check-in traces are of real human mobility. Prior work showed that significant amounts of Foursquare check-ins did not match with the physical mobility patterns of users, and suggested that misrepresented check-ins were incentivized by external rewards provided by the system. In this paper, our goal is to understand the root cause of inaccurate check-in data, by studying the validity of check-in traces in social media platforms without external rewards for check-ins. We conduct a data-driven analysis using an empirical check-in data trace of more than 276,000 users from WeChat Moments, with matching traces of their physical mobility. We develop a set of hypotheses on the underlying motivations behind people's inaccurate check-ins, and validate them using a detailed survey study. Our analysis reveals that there are surprisingly high amount of inaccurate check-ins even in the absence of rewards: 43% of total check-ins are inaccurate and 61% of survey participants report they have misrepresented their check-ins. We also find that inaccurate check-ins are often a result of user interface design as well as for convenience, self-advertisement and self-presentation.
Shopping Over Distance through a Telepresence Robot
Authors: Yang Lillian , Jones Brennan , Neustaedter Carman , Singhal Samarth
Published: November 2018

Computer mediated-communication tools (CMC) support loved ones in maintaining connections with one another over distance, yet it can be difficult to do activities together. We studied the use of telepresence robots for supporting distance-separated loved ones in engaging in the joint activity of shopping over distance. One partner shopped in person while the other used either a telepresence robot or a tablet from a remote location. Compared to the tablet group, we found that when partners communicated through a telepresence robot, the remote partner's personality and presence were expressed through the movements and physicality of the medium. However, the use of the telepresence robot introduced tension between partners regarding responsibility, dependency, and contribution to the act of shopping. These results demonstrate the benefits of a mobile embodiment for remote partners, as well as the need for greater physical capabilities to support both physical connection and remote contribution to leisure activities.
Learning by Doing versus Learning by Viewing
Authors: Yin Yue , Gurvich Itai , McReynolds Stephanie , Seys Debora , Van Mieghem Jan A.
Published: November 2018

We investigate how data-analyst productivity benefits from collaborative platforms that facilitate learning-by-doing (i.e. analysts learning by writing queries on their own) and learning-by-viewing (i.e. analysts learning by viewing queries written by peers). Learning is measured using a behavioral (productivity-improvement) approach. Productivity is measured using the time from creating an empty query to first executing it.

Using a sample of 2,001 data analysts at eBay Inc. who have written 79,797 queries from 2014 to 2018, we find that: 1) learning-by-doing is associated with significant productivity improvement when the analyst's prior experience focuses on the focally queried database; 2) only learning-by-viewing queries that are authored by analysts with high output rate (average number of queries written per month) is associated with significant improvement in the viewer's productivity; 3) learning-by-viewing also depends on the "social influence" of the author of the viewed query, which we measure 'locally' based on the number of the author's direct viewers per month or 'globally' based on the how the author's queries propagate to peers in the overall collaboration network. Combining results 2 and 3, when segmenting analysts based on output rate and 'local' social influence, the viewing of queries authored by analysts with high output but low local influence is associated with the largest improvement in the viewer's productivity; whereas when segmenting based on output rate and 'global' social influence, the viewing of queries authored analysts with high output and high global influence is associated with the largest improvement in the viewer's productivity.
Value-Sensitive Algorithm Design
Authors: Zhu Haiyi , Yu Bowen , Halfaker Aaron , Terveen Loren
Published: November 2018

Most commonly used approaches to developing automated or artificially intelligent algorithmic systems are Big Data-driven and machine learning-based. However, these approaches can fail, for two notable reasons: (1) they may lack critical engagement with users and other stakeholders; (2) they rely largely on historical human judgments, which do not capture and incorporate human insights into how the world can be improved in the future. We propose and describe a novel method for the design of such algorithms, which we call Value Sensitive Algorithm Design. Value Sensitive Algorithm Design incorporates stakeholders' tacit knowledge and explicit feedback in the early stages of algorithm creation. This increases the chance to avoid biases in design choices or to compromise key stakeholder values. Generally, we believe that algorithms should be designed to balance multiple stakeholders' needs, motivations, and interests, and to help achieve important collective goals. We also describe a specific project "Designing Intelligent Socialization Algorithms for WikiProjects in Wikipedia" to illustrate our method. We intend this paper to contribute to the rich ongoing conversation concerning the use of algorithms in supporting critical decision-making in society.
Characterizing Online Public Discussions through Patterns of Participant Interactions
Authors: Zhang Justine , Danescu-Niculescu-Mizil Cristian , Sauper Christina , Taylor Sean J.
Published: November 2018

Public discussions on social media platforms are an intrinsic part of online information consumption. Characterizing the diverse range of discussions which can arise is crucial for these platforms, as they may seek to organize and curate them. This paper introduces a framework to characterize public discussions, relying on a representation that captures a broad set of social patterns which emerge from the interactions between interlocutors, comments, and audience reactions.

We apply our framework to study public discussions on Facebook at two complementary scales. First, at the level of individual discussions, we use it to predict a discussion's future trajectory, anticipating future antisocial actions (such as participants blocking each other) and forecasting the discussion's growth. Second, we systematically analyze the variation of discussions across thousands of Facebook sub-communities, revealing subtle differences (and unexpected similarities) in how people interact when discussing online content. We further show that this variation is driven more by participant tendencies than by the content triggering these discussions.
Coordination Mechanisms for Self-Organized Work in an Emergency Communication Center
Authors: Zhang Zhan , Sarcevic Aleksandra
Published: November 2018

We describe an observational study of work coordination in an emergency communication center, where a collocated team of communication specialists engages in complex activities of communicating with pre-hospital medical teams, and coordinating patient care and transport. Unlike teams with clearly defined work roles and team structures that were introduced to increase work efficiency and minimize redundancy, the team we studied lacks the role differentiation. To better understand how complex work is accomplished under these conditions, we conducted in-situ observations in the center's control room and interviewed communication specialists. We found that communication specialists self-organized by using a mix of material and immaterial coordination mechanisms, including work schedules, computer systems, and tacit agreements to coordinate tasks. Using these findings, we then identified three features of self-organized, collocated and time-critical teamwork that require technology support: awareness of task ownership, task self-assignment, and informal team hierarchy. We conclude by discussing technology requirements to support these teamwork features.
News from the SIGs
Authors: Walker Ellen , Settle Amber
Published: November 2018

For this special issue celebrating the 50th anniversary of SIGCSE, we bring you greetings from Amber Settle, who also previews the conferences that SIGCSE will present as it begins its second half-century.
Nutritional supplementation boosts aerobic exercise effects on functional brain systems
Authors: Voss Michelle W. , Sutterer Matthew , Weng Timothy B. , Burzynska Agnieszka Z. , Fanning Jason , Salerno Elizabeth , Gothe Neha P. , Ehlers Diane K. , McAuley Edward , Kramer Arthur F.
Published: November 2018

There is growing evidence that aerobic exercise protects against age-related cognitive decline and that cardiorespiratory fitness is an important factor for these benefits. Studies also suggest that combining physical activity with cognitive enrichment is beneficial. We further examine these predictions by comparing effects of a nutritional supplement promoting exercise capacity to a lower-intensity activity with cognitive enrichment on functional network and cognitive outcomes that otherwise decline with aging. Inactive healthy older adults were randomized to one of four groups including a low-intensity activity with complex cognitive demands (dancing), walking, walking+supplement, or an active control. Results showed that walking+supplement increased salience network functional connectivity (FC), with less training benefit for default mode network FC. Although cognitive performance did not increase for any training group, participants in the walking+supplement group who were on medication that boosted key neurotransmitters (e.g., selective serotonin reuptake inhibitors) showed improved processing speed. Overall, this study provides new insight into how to boost the protective effects of exercise on brain systems that otherwise deteriorate with aging.

NEW & NOTEWORTHY Aerobic exercise effects on brain networks that otherwise decline with aging can be boosted with a nutritional supplement including beta-alanine. Beta-alanine supplementation could enhance the extent to which aerobic adaptations benefit the brain. In contrast, cognitive enrichment with low-intensity physical activity through dance did not affect functional networks. Medications that modulate neurotransmitters affected by aging (e.g., selective serotonin reuptake inhibitors) may modify effects of exercise on cognition.
Sensing Device Management for History‐Based Spectrum Sharing in Cognitive Radio Networks
Authors: Hawa Mohammed , Jubair Fahed , Al-Zubi Raed , Saifan Ramzi
Published: November 2018

A novel approach to managing a fully distributed cognitive radio network (CRN) is presented. This approach builds on the concept of history‐based spectrum access, in which cognitive base stations (BSs) independently estimate the system load using history records and adaptively swap their occupied spectrum bands to ensure allocation fairness and high overall throughput. In addition, cognitive BSs monitor primary user (PU) behavior in order to avoid interfering with active PUs. In this work, we address two issues that afflict history‐based access: the first is the high cost of the sensing devices needed at each cognitive BS to be able to independently draw conclusions about the status of the CRN and the second is the unreliability inherent in practical sensing hardware (such as energy detectors). Simulation results show that the proposed technique manages to solve the two abovementioned issues without any noticeable drop in performance and without sacrificing the distributed nature of the protocol.
Virulence of Aerial Conidia ofBeauveria bassianaProduced under LED Light toCtenocephalides felis(Cat Flea)
Authors: Pittarate Sarayut , Thungrabeab Malee , Mekchay Supamit , Krutmuang Patcharin
Published: November 2018

Ctenocephalides felisis an ectoparasitic flea species commonly found on dogs and cats. The current study verified thein vitrovirulence of conidia of the entomopathogenic fungusBeauveria bassianaproduced under different color LED light (red, blue, purple, green, yellow, and white) to adults ofC. felis. The fungal isolates were cultivated on malt extract agar (MEA). Bioassay treatments used aerial conidia in test tubes. Adult fleas were obtained from a house cat in Chiang Mai province, Thailand. The experiments were composed of one control and eleven treatment groups. All of the treatments withB. bassianaconidia caused adult mortality after an exposure of 12 h. Among the conditions used in this study,B. bassianacultured under red LED and fluorescent light were the most effective in causing mortality (100 %) in adult fleas after 36 h. The experimental results indicate that these aerial conidia ofB. bassianahave promising potential for use in control ofC. felisadult stages.
Self-Reported Benefit and Satisfaction with a Beamforming Body-Worn Hearing Aid for Elderly Adults
Authors: McPherson Bradley
Published: November 2018

Hearing impairment is a leading cause of disability globally and is particularly prevalent in elderly populations. Hearing aids are commonly recommended to mitigate the adverse effects on communication associated with hearing loss. However, the acceptability of hearing aids to elderly individuals is low and the majority of potential users do not wear hearing aids. Most hearing aids are designed with a discreet form factor in mind, to minimize device visibility. Given the range of comorbidities associated with hearing loss in the elderly, this conventional form factor may not always be optimal. The present study examined the experiences of elderly individuals with a recently developed, unconventional, body-worn hearing instrument, the EasyHear™ Grand (Logital Co. Ltd., Hong Kong). The bilaterally fitted instrument incorporates large controls, a color display, beamforming sound processing, and Bluetooth capabilities. Forty-three elderly participants (mean age=71; range 46-88 years) were surveyed to gauge level of benefit and satisfaction with the device and opinions regarding the hearing aid. They were assessed using three standardized questionnaires (the International Outcome Inventory-Hearing Aids, the Profile of Hearing Aid Benefit, and the Client Oriented Scale of Improvement) and through open-ended, structured interviews. Participants rated their EasyHear device fitting highly for hours of use and improved quality of life and rated the device favorably for improved communication and benefit in background noise. A majority of users felt the device improved listening ability in their expressed area of greatest need, and also for their second highest prioritized area of greatest need. Less than 10% of users felt their listening was only occasionally or hardly ever improved when using the body-worn device. Benefit and satisfaction ratings with the EasyHear Grand were comparable to those in studies involving conventional form factor devices. Interviews highlighted areas where users felt the device could be improved—extra noise reduction, changes to device dimensions, receiver/eartip fit, and cableless technology were among the areas mentioned. Many participants valued smartphone linkage and Bluetooth capability. The EasyHear Grand, with its body-worn design and large, simple controls, was well accepted by the majority of participants. Hearing aids that break from conventional design formats may benefit many elderly individuals with hearing impairment and promote increased user acceptability.
Research on Experimental Method for Obtaining Independent Combustion Noise of Internal Combustion Engine
Authors: Xiang Yang , Yao Jiachi , Zhou Qiang , Qian Sichong , Wang Shuai
Published: November 2018

Internal combustion engine noise sources are complex and changeable. Combustion noise is usually drowned out by mechanical noise and aerodynamic noise. Traditional noise source identification methods can only qualitatively identify combustion noise. In order to quantitatively obtain the independent pure combustion noise of an internal combustion engine, it is necessary to design and build a separate noise source simulation test bench. In this paper, the combustion noise separation test bench based on transfer function method is designed and implemented. In the test, a pressure pulse device is installed in the combustion chamber. When the piston is at top dead center (TDC), pulse pressure is generated to excite the internal combustion engine to radiate noise. The pressure signal and noise signal are utilized to obtain the transfer function of combustion pressure and noise. Then, according to the cylinder pressure and transfer function, the combustion noise can be directly calculated. The test was carried out on 4120SG diesel engine. Experimental results show that when the internal combustion engine is under 1500 rpm and no‐load condition and 800 rpm and no‐load condition, the frequency components of independent pure combustion noise are both mainly concentrated at 1100 Hz, 1400 Hz, and 3000 Hz. Furthermore, the internal combustion engine vibration test method and the combustion noise empirical formula calculation method are both carried out to show accuracy and effectiveness of the obtained independent combustion noise through the combustion noise separation test based on transfer function method.
Restricted Boltzmann Machine‐Assisted Estimation of Distribution Algorithm for Complex Problems
Authors: Bao Lin , Sun Xiaoyan , Chen Yang , Man Guangyi , Shao Hui
Published: November 2018

A novel algorithm, called restricted Boltzmann machine‐assisted estimation of distribution algorithm, is proposed for solving computationally expensive optimization problems with discrete variables. First, the individuals are evaluated using expensive fitness functions of the complex problems, and some dominant solutions are selected to construct the surrogate model. The restricted Boltzmann machine (RBM) is built and trained with the dominant solutions to implicitly extract the distributed representative information of the decision variables in the promising subset. The visible layer’s probability of the RBM is designed as the sampling probability model of the estimation of distribution algorithm (EDA) and is updated dynamically along with the update of the dominant subsets. Second, according to the energy function of the RBM, a fitness surrogate is developed to approximate the expensive individual fitness evaluations and participates in the evolutionary process to reduce the computational cost. Finally, model management is developed to train and update the RBM model with newly dominant solutions. A comparison of the proposed algorithm with several state‐of‐the‐art surrogate‐assisted evolutionary algorithms demonstrates that the proposed algorithm effectively and efficiently solves complex optimization problems with smaller computational cost.
Molding of Polymeric Composite Reinforced with Glass Fiber and Ceramic Inserts: Mathematical Modeling and Simulation
Authors: Porto Túlio R. N. , Júnior Wanderley F. A. , De Lima Antonio G. B. , De Lima Wanderson M. P. B. , Lima Hallyson G. G. M.
Published: November 2018

This work provides a numerical study of a polymer composite manufacturing by using liquid composite material molding. Simulation of resin flow into a porous media comprising fiber perform (reinforcement) inserted in a mold with preallocated ceramic inserts has been performed, using the Ansys FLUENT® software. Results of resin volumetric fraction, stream lines and pressure distribution inside the mold, and mass flow rate (inlet and outlet gates) of the resin, as a function of filling time, have been presented and discussed. Results show that the number of inserts affects the filling time whereas the distance between them has no influence in a process.
Iterative Learning Control for Linear Discrete‐Time Systems with Randomly Variable Input Trail Length
Authors: Wei Yun-Shan , Xu Qing-Yuan
Published: November 2018

For linear discrete‐time systems with randomly variable input trail length, a proportional‐ (P‐) type iterative learning control (ILC) law is proposed. To tackle the randomly variable input trail length, a modified control input at the desirable trail length is introduced in the proposed ILC law. Under the assumption that the initial state fluctuates around the desired initial state with zero mean, the designed ILC scheme can drive the ILC tracking errors to zero at the desirable trail length in expectation sense. The designed ILC algorithm allows the trail length of control input which is different from system state and output at a specific iteration. In addition, the identical initial condition widely used in conventional ILC design is also mitigated. An example manifests the validity of the proposed ILC algorithm.
Asymptotic Behavior of a Stochastic Two‐Species Competition Model under the Effect of Disease
Authors: Liu Rong , Liu Guirong
Published: November 2018

This paper is concerned with a stochastic two‐species competition model under the effect of disease. It is assumed that one of the competing populations is vulnerable to an infections disease. By the comparison theorem of stochastic differential equations, we prove the existence and uniqueness of global positive solution of the model. Then, the asymptotic pathwise behavior of the model is given via the exponential martingale inequality and Borel‐Cantelli lemma. Next, we find a new method to prove the boundedness of the pth moment of the global positive solution. Then, sufficient conditions for extinction and persistence in mean are obtained. Furthermore, by constructing a suitable Lyapunov function, we investigate the asymptotic behavior of the stochastic model around the interior equilibrium of the deterministic model. At last, some numerical simulations are introduced to justify the analytical results. The results in this paper extend the previous related results.
Collision‐Free Path‐Planning for Six‐DOF Serial Harvesting Robot Based on Energy Optimal and Artificial Potential Field
Authors: Luo Lufeng , Wen Hanjin , Lu Qinghua , Huang Haojie , Chen Weilin , Zou Xiangjun , Wang Chenglin
Published: November 2018

Collision‐free autonomous path planning under a dynamic and uncertainty vineyard environment is the most important issue which needs to be resolved firstly in the process of improving robotic harvesting manipulator intelligence. We present and apply energy optimal and artificial potential field to develop a path planning method for six degree of freedom (DOF) serial harvesting robot under dynamic uncertain environment. Firstly, the kinematical model of Six‐DOF serial manipulator was constructed by using the Denavit‐Hartenberg (D‐H) method. The model of obstacles was defined by axis‐aligned bounding box, and then the configuration space of harvesting robot was described by combining the obstacles and arm space of robot. Secondly, the harvesting sequence in path planning was computed by energy optimal method, and the anticollision path points were automatically generated based on the artificial potential field and sampling searching method. Finally, to verify and test the proposed path planning algorithm, a virtual test system based on virtual reality was developed. After obtaining the space coordinates of grape picking point and anticollision bounding volume, the path points were drew out by the proposed method. 10 times picking tests for grape anticollision path planning were implemented on the developed simulation system, and the success rate was up to 90%. The results showed that the proposed path planning method can be used to the harvesting robot.
Synthesis, Characterization, and Cytotoxic Evaluation of Some Newly Substituted Diazene Candidates
Authors: El-Naggar Mohamed , El-Shorbagi Abdel-Nasser , Elnaggar Dina H. , Amr Abd El-Galil E. , Al-Omar Mohamed A. , Elsayed Elsayed A.
Published: November 2018

A series of azocompounds containing methyl salicylate 4a–k and 1-naphthyl moiety 6–8 was synthesized and tested as anticancer agents. Nitrosation of methyl 5-amino-2-hydroxybenzoate or 1-aminonaphthalene by using NaNO2 in the presence of HCl afforded diazonium salt derivatives 2 and 5, which were treated with substituted imino or substituted amino derivatives, to give the corresponding substituted amino-pent-2-en-3-yl-diazenylbenzoate 4a–k or 2-substituted-1-(naphthalen-1-yl)diazene derivatives 6a–h, 7a,b, and 8a,b. All the synthesized compounds were elucidated by elemental analysis and spectroscopic evidence.
Differentiation of Human Embryonic Stem Cells to Sympathetic Neurons: A Potential Model for Understanding Neuroblastoma Pathogenesis
Authors: Carr-Wilkinson Jane , Prathalingam Nilendran , Pal Deepali , Moad Mohammad , Lee Natalie , Sundaresh Aishwarya , Forgham Helen , James Peter , Herbert Mary , Lako Majlinda , Tweddle Deborah A.
Published: November 2018

Background and Aims. Previous studies modelling human neural crest differentiation from stem cells have resulted in a low yield of sympathetic neurons. Our aim was to optimise a method for the differentiation of human embryonic stem cells (hESCs) to sympathetic neuron-like cells (SN) to model normal human SNS development.Results. Using stromal-derived inducing activity (SDIA) of PA6 cells plus BMP4 and B27 supplements, the H9 hESC line was differentiated to neural crest stem-like cells and SN-like cells. After 7 days of PA6 cell coculture, mRNA expression ofSNAILandSOX-9neural crest specifier genes and the neural markerperipherin(PRPH) increased. Expression of the pluripotency markerOCT 4decreased, whereasTP53andLIN28Bexpression remained high at levels similar to SHSY5Y and IMR32 neuroblastoma cell lines. A 5-fold increase in the expression of the catecholaminergic markertyrosine hydroxylase (TH) and the noradrenergic markerdopamine betahydroxylase (DBH) was observed by day 7 of differentiation. Fluorescence-activated cell sorting for the neural crest marker p75, enriched for cells expressingp75,DBH,TH, andPRPH, was more specific than p75 neural crest stem cell (NCSC) microbeads. On day 28 post p75 sorting, dual immunofluorescence identified sympathetic neurons by PRPH and TH copositivity cells in 20% of the cell population. Noradrenergic sympathetic neurons, identified by copositivity for both PHOX2B and DBH, were present in 9.4% ± 5.5% of cells.Conclusions. We have optimised a method for noradrenergic SNS development using the H9 hESC line to improve our understanding of normal human SNS development and, in a future work, the pathogenesis of neuroblastoma.
Categorical Cross‐Recurrence Quantification Analysis Applied to Communicative Interaction during Ainsworth’s Strange Situation
Authors: Lira-Palma Danitza , González-Rosales Karolyn , Castillo Ramón D. , Spencer Rosario , Fresno Andrés
Published: November 2018

The goal of this study was to characterize the degree of structuring of verbal and motor behaviours, unfolded during the application of an procedure called the Strange Situation. This procedure is used for assessing children’s attachment quality during early stages of their development. Many studies have demonstrated that communicative interactions share features with complex dynamic systems. In such studies, estimations of degree of structure have been used to characterize the system’s synchronization. Thus, assuming that processes of communicative interaction occur in the Strange Situation procedure, it was expected to find traces of synchronization. The metrics were estimated through a Categorical Cross‐Recurrence Quantification Analysis applied to the behaviours of individuals and dyads. Two applications of the Strange Situation were implemented and recorded. Verbal and motor interactions among children, caregivers, and strangers were transcribed, categorized, and organized as time series. From each time series of original behaviours, randomized time series were created. Measures of recurrence extracted from Recurrent Plots, such as determinism, entropy, maximum line, laminarity, and trapping time, were calculated. Original and randomized time series were compared in terms of these measures. Results indicated that communicative interaction during the Strange Situation had a structure that mimics properties observed in social interactions where synchronization emerges. In our case, verbal behaviours were more prone to synchronization than motor behaviours, in both individuals and dyads, even though this pattern was more salient among caregivers and strangers than children. The relevance of having measures that can capture synchronization during the administration of the Strange Situation is discussed. Our preliminary findings allow us to point out that the application of RQA and C‐RQA to the Strange Situation could not only contribute to methodology, but also contribute to emphasizing the role of coupling in communicative interaction generated by the application of this procedure to measure attachment patterns.
Finite Volume Element Approximation for the Elliptic Equation with Distributed Control
Authors: Wang Quanxiang , Zhao Tengjin , Zhang Zhiyue
Published: November 2018

In this paper, we consider a priori error estimates for the finite volume element schemes of optimal control problems, which are governed by linear elliptic partial differential equation. The variational discretization approach is used to deal with the control. The error estimation shows that the combination of variational discretization and finite volume element formulation allows optimal convergence. Numerical results are provided to support our theoretical analysis.
Video Capsule Endoscopy in the Assessment of Portal Hypertensive Enteropathy
Authors: Al-Azzawi Yasir , Spaho Lidia , Mahmoud Mohammed , Kheder Joan , Foley Anne , Cave David
Published: November 2018

Background. The features of the portal hypertension enteropathy (PHE) vary from mild mucosal changes to varices with or without bleeding. The prevalence and the development are not fully understood. Aim. Our aim is to examine the prevalence and the different manifestations of PHE using video capsule endoscopy (VCE). Methods. It is a single center retrospective study of patients with cirrhosis, who had VCE. Based on the published literature, we divided the PHE lesions into vascular lesions and mucosal lesions. Results. Of the 100 patients with cirrhosis that had a VCE study, the mean age was 62.82 years. Male gender was predominant (64%), while Caucasians represented 82% of the cohort. The most common etiology of cirrhosis was chronic alcohol abuse followed by chronic hepatitis C virus and nonalcoholic steatohepatitis. VCE detected small bowel lesions in 71% of the patients while the features of PHE were found in 65% from the total cohort. AVMs and inflammatory changes were the most common findings, followed by bleeding. More than 50% of the lesions were vascular in nature. The risk of finding PHE in decompensated cirrhosis is twice that in compensated cirrhosis. Forty-five patients had negative EGD exam for any active bleeding, esophageal varices, portal hypertensive gastropathy, or gastric varices. Of these, 69% had features of PHE in their VCE. Conclusions. VCE detected small bowel lesions in 71% of our cohort. There is a high prevalence of PHE in decompensated cirrhosis. Vascular lesions are the most common finding in the small bowel of this population.