Dynamic Online Research Articles

Compensation for Delays and Losses of Packages in Dynamic Online Games

A couple of decades ago, data rates on the network were measured in kilobytes per second, and even then, online game developers had some problems with the packet loss and transmission delays. Now the transfer rate is hundreds of times higher, and the problem of delay compensation is even more relevant.For many dynamic online games, a transmission delay of as little as 20 ms can be quite noticeable, negatively affecting the gameplay and emotions of the game, which can repel players.The problem is exacerbated by the fact that along with the need to compensate for the time of delivery of packets, on the client side there are other non-network factors that are beyond the control of developers, which make the total delay 5-10 ms longer. Because of this, the desire to get rid of network delays as much and as well as possible becomes a necessity, and developers are forced to look for optimal ways to solve this problem.The problem statement is as follows: to review the causes of delays in online games and possible solu- tions, as well as the advantages and disadvantages of certain approaches. The problem is considered at the 4 levels of the TCP / IP network model, as well as at the application level. The approaches are given for the most commonly used protocols for each layer, but basic ideas can be easily transferred to other implementations.The main causes of delays under consideration: propagation delay, router queue delay, transmission delay, and processing delays.This article shows the impact of network delays on the online games and the ways to compensate for them, along with the theory of data transmission protocols in the network and the ways to solve the problems that arise in the development of algorithms.Recommendations for solving the compensation problem can be taken into account when designing and launching online shooters, strategies, etc. Thanks to the given receptions it is possible to minimize the general delay on the transfer of packets in a network, thanks to which the game on the client looks as if the player plays in the Single Player mode.

Alientoma, a Dynamic Database for Alien Insects in Greece and Its Use by Citizen Scientists in Mapping Alien Species.

Simple SummaryBiological invasions have become one of the most intimidating environmental and economic threats of our time as a result of the globalisation and the rise in international commerce, with alien insects representing one of the most abundant groups of organisms introduced into Europe. Over the last decade, citizen science has emerged as a valuable tool for the early detection and monitoring of alien species worldwide. The aim of this study is to introduce a dynamic checklist and database of these organisms in Greece, where a large number of alien insect species have been detected. Alientoma—derived from “alien” and the Greek word “entoma”, meaning insects—was created to provide information on alien species (i.e., status, distribution, taxonomy, common names, and impacts) to the public as well as to the scientific community in order to inform and assist in the mitigation of their adverse impacts. This project was promoted through news agencies, both in the press and television, while it also maintained a strong social media presence. Since its launch, 1512 sessions were performed by individuals mainly from Greece and Cyprus. An initial network of citizen scientists has been established and is expected to grow in the near future.Invasive alien species have been increasingly acknowledged as a major threat to native biodiversity and ecosystem services, while their adverse impacts expand to human health, society and the economy on a global scale. Insects represent one of the most numerous alien organismic groups, accounting for about one fifth of their total number. In Greece, a large number of alien insects have been identified, currently reaching 469 species. In recent decades, the contribution of citizen science towards detecting and mapping the distribution of alien insects has been steeply increasing. Addressing the need for up-to-date information on alien species as well as encouraging public participation in scientific research, the Alientoma website—derived from “alien” and the Greek word “entoma”, meaning insects, is presented. The website aims towards providing updated information on alien species of insects to the public as well as the scientific community, raising awareness about biological invasions and addressing their distribution and impacts inter alia. By maintaining a dynamic online database alongside a strong social media presence since its launch, Alientoma has attracted individuals mainly from Greece and Cyprus, interacting with the website through a total of 1512 sessions. Alientoma intends to establish a constantly increasing network of citizen scientists and to supplement early detection, monitoring and management efforts to mitigate the adverse impacts of alien insects in Greece.

EnTIRE: Mapping Normative Frameworks for EThics and Integrity of REsearch

Background: The areas of Research Ethics and Research Integrity (RE+RI) are rapidly evolving. In the EU and internationally, new legislation, codes of conduct and good practices are constantly being developed. New technologies (e.g. gene editing), complex statistical methods (e.g. biostatistics), pressure to publish and obtain grants, and growing emphasis on stakeholder driven science (e.g. public-private partnerships) increase the complexity of conducting science. In this complex and dynamic environment, researchers cannot easily identify the correct rules and best tools for responsible conduct of research. This also increasingly constitutes a challenge for RE+RI experts. Aim: Our aim is to create a platform that makes the normative framework governing RE+RI easily accessible, supports application in research and evaluation, and involves all stakeholders in a participatory way, thus achieving sustainability. The platform will foster uptake of ethical standards and responsible conduct of research, and ultimately support research excellence and strengthen society’s confidence in research and its findings. Vision: Our vision is that in order to make the normative framework governing RE+RI accessible, a dynamic online Wiki-platform, owned by the community of RE+RI stakeholders, is needed. The value of this platform will lie in the availability of practical information on how to comply with EU, national and discipline-specific RE+RI standards and legislation, including information on rules and procedures, educational materials, and illustrative cases and scenarios. Adopting open science (open source and open data) approaches, the platform will be easy to use, by applying novel techniques for data collection and comparison, enabling users to navigate quickly and intuitively to appropriate content. In order to keep the platform up-to-date and sustainable, it will be based upon active involvement of the RE+RI community, and will contribute to further development of this community by providing a podium for reflection and dialogue on RE+RI norms and practices. Objectives: EnTIRE’s work packages (WP) will: undertake an in-depth stakeholder consultation across EU countries exploring RE+RI experiences and practices in order to define the boundaries of data to be collected, and developing a mapping structure adapted to user needs (WP 2); assemble the relevant normative elements, including RE+RI rules and procedures, educational materials, and illustrative casuistry, and identify relevant institutions across EU countries (WP 3-5); develop a user-friendly Wiki-platform and online resources to foster and facilitate responsible research practices and to promote compliance amongst European researchers with RE+RI standards and pertinent legislation and regulations (WP 6); and foster further development of the RE+RI community, that will support the platform and be supported by it, will keep the information up-to-date, disseminate the project’s findings and develop innovative strategies for maintaining the platform and building relationships to relevant organisations for further dissemination, including sustainable funding (WP 7). Relevance to the work programme: The proposed project responds directly to the core requirement of call SwafS-16-2016 to ‘provide a dynamic mapping of the RE+RI normative framework which applies to scientific research conducted in the EU and beyond’. Our proposal does this by using a participatory approach, stimulating knowledge transfer regarding codes and regulations, resources and institutions, and cases, by applying innovative ICT solutions and open science approaches, and by further developing a community of active users, to enable sustainability after the end of the project.

Design and application of groundwater dynamic online monitoring system in Aeolian desertification area

Populus euphratica, at Tarim Nature Reserve, growing in their natural habitat represents a valuable resource for the surface vegetation on the response mechanism to underground water level. In order to study the distribution of the groundwater level in Aeolian desertification areas, aiming at the current situation of groundwater dynamic online monitoring in Aeolian desertification areas, the network was effectively used to simplify data processing, increase the function of forecast and warning and optimize the power supply system. The results show that the equipment installed in Aeolian desertification areas has completed the remote transmission of data and data analysis. Based on the 25d real-time monitoring data, the groundwater level fluctuates between 0.604 and 1.515 m. Based on the table of groundwater level threshold of populus euphratica growth, the groundwater level at this location is between 0.50 and 4.71 m, and has not crossed the threshold of good growth and stress. Therefore, populus euphratica is growing well, and the equipment does not produce early warning information. Field investigation shows that populus euphratica grows well in this area, and there are many new seedlings germination, which is consistent with the data. Thus, the groundwater monitoring system can be used for dynamic monitoring of groundwater level in Aeolian desertification areas.

A Real-Time Peak Extraction Algorithm for Dynamic Displacement Measurement Based on Spectral Confocal Microscopy

Spectral confocal is widely used in various fields such as topography detection, roughness measurement, thickness measurement, for its advantages ability in displacement measurement. Developed from confocal microscopy, the spectral confocal microscopy greatly improves the efficiency of displacement measurement because there is no need for longitudinal scanning, In other words, we need to obtain the wavelength information corresponding to the peak point of the spectral signal, which is called peak abscissa but not the peak value. Therefore, Accurate and efficient peak abscissa calculation algorithm occupies an important position in displacement monitoring based on spectral confocal. However, the existing methods are too complex to apply to real-time dynamic online detection, for they usually focus on determining the peak value by means of curve fitting and peak extraction. In this paper, we proposed an efficient and accurate peak abscissa calculation method by shifting, difference, linear fitting, zero point and peak abscissa calculation (SDLZ). Compared with the Gaussian fitting method, the results demonstrate that the SDLZ can greatly improve efficiency, can be applied to field programmable gate array microcontrollers, with high measurement accuracy, providing key solutions for equipment needs.

Model free adaptive control design for a tilt trirotor unmanned aerial vehicle with quaternion feedback: Theory and implementation

SummaryThis article focuses on the attitude and altitude tracking control of the tilt trirotor unmanned aerial vehicle (UAV) which is subject to modeling uncertainties and unknown external disturbances. A novel model free adaptive controller is designed to achieve asymptotic tracking control of the UAV attitude and altitude channels. The control scheme is based on the data driven strategy, and relies on the input/output data to estimate the system dynamics online. Furthermore, the discrete sliding mode algorithm is combined to enhance the system robustness, and the quaternion feedback is employed to avoid the singularity associated with the attitude control design. The stability of closed‐loop system and the convergence of the tracking errors are proved. And real time flight experiments are preformed on a tilt trirotor UAV control testbed. The experimental results verify the effectiveness of the proposed control scheme and achieve a strong robustness with respect to the modeling uncertainties and unknown external disturbances.

Distributed cooperative neural control of a class of nonlinear multi‐agent systems with unknown time‐varying control coefficient

SummaryThis article studies the leader–follower cooperative tracking problem of a class of multi‐agent systems with unknown nonlinear dynamics. As the load of the following agent may be changing throughout the whole work process, we consider the control coefficient of the following agent to be time‐varying and nonlinear instead of constant, which is more practical. All agents are connected by the directed communication graph with weighted topology. The followers can have unknown nonidentical nonlinear dynamics and external disturbances. The nonautonomous leader generates the reference trajectory for only part of the followers and others can only receive the information from their neighbors. To achieve the ultimate synchronization of all following agents to the leader, the novel cooperative adaptive control protocols are designed based on the neural approximation and adaptive updating mechanism. A novel singularity‐avoided adaptive updating law is proposed to estimate the control coefficient and compensate for the unknown dynamics online. Lyapunov theory is used to prove the ultimate boundedness of the synchronization tracking error. The correctness and effectiveness of the presented control scheme are demonstrated by two simulations in SISO and MIMO cases, respectively.

Dynamic Online User Recruitment With (Non-) Submodular Utility in Mobile CrowdSensing

Mobile CrowdSensing (MCS) has recently become a powerful paradigm that recruits users to cooperatively perform various tasks. In many realistic settings, users participate in real time and we have to recruit them in an online manner. The existing works usually formulate the online recruitment problem as a budgeted optimal stopping problem with submodular user utility, while we first argue that not only the budget but also the time constraints can jointly influence the recruitment performance. For example, if we have less budget but plenty of time, we should recruit users with more patience. Second, considering the user’s cooperative willingness, its contribution may be diminishing or even irregular. Hence, we also need to address not only submodular cases but also their non-submodular utility. In this paper, we study the online user recruitment problem with (non-)submodular utility under the budget and time constraints. To deal with the two constraints, we first estimate the number of users to be recruited and then recruit them in segments. Moreover, we extend the segmented strategy with a non-submodular utility, which has the submodularity ratio <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\gamma $ </tex-math></inline-formula> and the competitive ratio <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\gamma ^{2}(1-e^{-1})/7$ </tex-math></inline-formula> . Furthermore, to correct estimation errors and utilize newly obtained information, we dynamically re-adjust the segmented strategy and also prove that the dynamic strategy achieves a competitive ratio of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\gamma ^{2}(1-e^{-1})(1-e^{-\gamma /2})/7}$ </tex-math></inline-formula> . Finally, a reverse auction-based online pricing mechanism is lightly built into the proposed user recruitment strategy, which achieves truthfulness and individual rationality. Extensive experiments on three real-world data sets validate the proposed online user recruitment strategy under the (non-) submodular utility and two constraints.

Expectation Modulates Performance Above the Effect of Attention in Two Dynamic Online Experiments

Expectation Modulates Performance Above the Effect of Attention in Two Dynamic Online Experiments

A dynamic online nomogram predicting severe vitamin D deficiency at ICU admission

Although prevalent and associated with worsened outcomes, vitamin D severe deficiency is not systematically searched among intensive care unit (ICU) admissions and waiting time for measurement results range from hours to few days. Hence, we developed and internally validated a simple nomogram for predicting severe vitamin D deficiency at ICU admission. Data of 3338 ICU admissions from an observational prospective cohort registered between January 2017 and December 2019 were analyzed. Demographic data as well as severity scores and season of admission were obtained. After splitting the population into training and test sets, a least absolute shrinkage (LASSO) regression model was used to select factors and construct the nomogram. Calibration and discrimination were used to assess the nomogram performance. Clinical use was evaluated by a decision curve analysis. Age, gender, Sequential Organ Failure Assessment (SOFA), Simplified Acute Physiology Score III (SAPS3) and season of admission were identified by the LASSO regression analysis as significant predictors of vitamin D severe deficiency at ICU admission. The nomogram model showed good discrimination with a 1000 bootstrap analysis and good calibration with a C-index of 0.64. The decision curve analysis showed that at a threshold probability between 30% and 50%, using the nomogram adds more benefit that considering that all patients are severely deficient or non-severely deficient. This easy-to-use dynamic nomogram can help physicians to select patients that could benefit the most from vitamin D supplementation at ICU admission. External validation is needed to verify the generalizability of this nomogram.

Cactaceae at Caryophyllales.org – a dynamic online species-level taxonomic backbone for the family

This data paper presents a largely phylogeny-based online taxonomic backbone for the Cactaceae compiled from literature and online sources using the tools of the EDIT Platform for Cybertaxonomy. The data will form a contribution of the Caryophyllales Network for the World Flora Online and serve as the base for further integration of research results from the systematic research community. The final aim is to treat all effectively published scientific names in the family. The checklist includes 150 accepted genera, 1851 accepted species, 91 hybrids, 746 infraspecific taxa (458 heterotypic, 288 with autonyms), 17,932 synonyms of accepted taxa, 16 definitely excluded names, 389 names of uncertain application, 672 unresolved names and 454 names belonging to (probably artificial) named hybrids, totalling 22,275 names. The process of compiling this database is described and further editorial rules for the compilation of the taxonomic backbone for the Caryophyllales Network are proposed. A checklist depicting the current state of the taxonomic backbone is provided as supplemental material. All results are also available online on the website of the Caryophyllales Network and will be constantly updated and expanded in the future. Citation: Korotkova N., Aquino D., Arias S., Eggli U., Franck A., Gómez-Hinostrosa C., Guerrero P. C., Hernández H. M., Kohlbecker A., Köhler M., Luther K., Majure L. C., Müller A., Metzing D., Nyffeler R., Sánchez D., Schlumpberger B. & Berendsohn W. G. 2021: Cactaceae at Caryophyllales.org – a dynamic online species-level taxonomic backbone for the family. – Willdenowia 51: 251–270. Version of record first published online on 31 August 2021 ahead of inclusion in August 2021 issue. Data published through: http://caryophyllales.org/cactaceae/Checklist

Co-creation of services: an online network perspective

PurposeIn the co-creation process from a network perspective, service is produced, designed, and evaluated entirely by the actors with dynamic roles and with less participation by the firm's employees in the service process. The purpose of this paper is to develop a theoretical model that represents environmental stimuli and value perceptions that contribute to service co-creation behaviour in an online network.Design/methodology/approachA total of 36 semi-structured interviews were conducted with members of two online programming communities – GitHub and Stack Overflow co-creators, with the data analysed using thematic analysis. The stimulus-organism-response model guided the development of the final model.FindingsSocial influence and trust are influential in actor value perceptions, including primary and network value, the interplay of which leads actors to co-production, supportive, and administrative behaviour. Environmental factors do not directly drive actors; rather it is the value that initiates and drives actors, which, by extension, initiates and drives the co-creation of services.Research limitations/implicationsThe service co-creation behaviour model provides a basis for future research in the co-creation and co-destruction context to model behaviours within the online network organisation setting and thereby enable improvement of such systems. This model can be operationalised in a network environment through design features.Originality/valueThis paper provides a rich understanding of environmental stimuli and value perception factors that contribute to the co-creation of services, and identifies different types of behaviours in dynamic online networks. This paper presents a new model of different types of behaviours emerging from actor participation in the co-creation process.

A joint energy efficiency optimization scheme based on marginal cost and workload prediction in data centers

With the widespread development of cloud computing, the dramatic increase in the number and size of data centers (DCs) has resulted in substantial energy consumption and serious environmental problems. This creates a challenge for the further development of DCs. It is imperative to improve the overall energy efficiency of DCs. According to the statistics, servers and cooling systems are the main energy-consuming components of DCs. Recently, several energy-efficient strategies have been developed to address these problems. However, most of these works only consider the energy optimization of servers or cooling systems separately. Therefore, a Joint Energy Efficiency Optimization Scheme (JEES) is proposed in this paper, where the energy consumed by servers and the cooling system is jointly considered, and coordinately optimized. JEES includes a dynamic online task scheduling algorithm based on marginal cost evaluation, a resource management strategy that integrates the workload prediction technique to manage resources, and a task migration method using marginal cost evaluation. By using the proposed techniques, the total energy consumption of DCs can be reduced. Extensive experiments have been conducted based on real-world workload traces, and the results demonstrate that compared with other techniques, the proposed scheme effectively improves the overall resource utilization and reduces the total energy consumption of DCs.

Nearly Optimal Integral Sliding-Mode Consensus Control for Multiagent Systems With Disturbances

This article considers integral sliding-mode control (ISMC) for multiagent systems with matched disturbances through adaptive dynamic programming (ADP) method. A distributed disturbance observer (DDO) is designed for each agent to generate the disturbance estimation. Using the disturbance estimation, an ISMC scheme is proposed to reject the input disturbance and obtain the equivalent local neighbor consensus sliding-mode dynamics. Then, a discount performance function is designed for each agent, and ADP technique is utilized to address the optimal consensus control for the equivalent sliding-mode dynamics online. Based on the gradient descent algorithm, we propose the adaptive weight tuning laws for the critic-actor neural networks (NNs) to carry out the ADP method. Furthermore, the local neighbor consensus errors and the weight estimation errors for the critic-actor NNs are proved to be uniformly ultimately bounded (UUB). Finally, the practical example is applied to validate the effectiveness of our results.

Adaptive robust barrier‐based control of a 3D flexible riser system subject to boundary displacement constraints

AbstractThis article involves an adaptive robust barrier‐based control of a three‐dimensional riser system subject to system uncertainties and output constraints. A barrier‐based Lyapunov function and a dynamical online update technique are merged to develop new adaptive robust control schemes for dampening the vibration, compensating for parametric uncertainties, and dealing with the constraints in the system. A rigorous Lyapunov analysis is exploited to guarantee the uniformly bounded stability in the controlled system. Finally, the efficacy of the designed approach is validated via simulation results.

3D printing in oral and maxillofacial surgery: a nationwide survey among university and non-university hospitals and private practices in Germany.

Oral and maxillofacial surgery (OMFS) has undergone pioneering progress through the development of three-dimensional (3D) printing technologies. The aim of this study was to evaluate the use of 3D printing at OMFS university and non-university hospitals and private practices in Germany. For explorative assessment, a dynamic online questionnaire containing 10-22 questions about the current use of 3D printing and the reasons behind it was sent to OMFS university and non-university hospitals and private practices in Germany by the study group from the German Association of Oral and Maxillofacial Surgery (DGMKG). In total, 156 participants responded from university (23 [14.7%]) and non-university hospitals (19 [12.2%]) and private practices without (85 [50.5%]) and with 29 (18.6%) inpatient treatment facility. Highest applications of 3D printing were in implantology (57%), microvascular bone reconstructions (25.6%), and orthognathics (21.1%). Among the participants, 37.8% reportedly were not using 3D printing. Among the hospitals and private practices, 21.1% had their own 3D printer, and 2.5% shared it with other departments. The major reason for not having a 3D printer was poor cost efficiency (37.6%). Possessing a 3D printer was motivated by independence from external providers (91.3%) and rapid template production (82.6%). The preferred printing methods were stereolithography (69.4 %) and filament printing (44.4%). OMFS 3D printing is established in Germany with a wide range of applications. The prevalence of 3D printing in hospitals and private practices is moderate. This may be enhanced by future innovations including improved cost efficiency.

Online Examination System – A Web-Based Application

Today PHP's online test system has become a rapidly growing test method, due to its speed and accuracy. Less work is also necessary to carry out the test. Nearly all organizations now perform their objective exams online, saves time for exams for students. Organizations can also easily monitor the student's performance during an exam. As a consequence, the results will be released in less time. It also saves paper to help the environment. In php, the online exam paper is very useful to learn according to current requirements. This paper uses a PHP script with Mysql database online test system. So, you are looking for any educational paper or build small PHP systems with the Mysql database, so you're in the right position. Because the solution to your needs can be found in this post. Here we will build a PHP online exam application with the Mysql database to assist you in creating your final year paper for your education. And if you are a PHP programmer beginner and learn how to use any PHP dynamic online system, this article will help.

Dynamic online convex optimization with long-term constraints via virtual queue

In this paper, we investigate the online convex optimization (OCO) with long-term constraints which is widely used in various resource allocations and recommendation systems. Different from the most existing works, our work adopts a dynamic benchmark to analyze the optimization performance since the dynamic benchmark is more common than the static benchmark in practical applications. Moreover, compared with many constrained OCO works ignoring the Slater condition, we study the effect of the Slater condition on the constraint violation bounds and obtain the better performance of the constraint violations when the Slater condition holds. More importantly, we propose a novel iterative optimization algorithm based on the virtual queues to achieve sublinear regret and constraint violations. Finally, we apply our dynamic OCO model to a resource allocation problem in cloud computing and the results of the experiments validate the effectiveness of our algorithm.

DDQN-TS: A novel bi-objective intelligent scheduling algorithm in the cloud environment

Task scheduling has always been one of the crucial problem in cloud computing. With the transition of task types from static batch processing to dynamic stream processing, the dynamic online task scheduling problem has attracted widespread attention. At this stage, explore an effective task scheduling method to implement high quality of service (QoS) requests with limited resources is a considerable challenge. This paper proposes a novel scheduling algorithm called double deep Q-network task scheduling (DDQN-TS), which uses the adaptive learning ability of double deep Q-network (DDQN) to explore the optimal task scheduling strategy. Experiments conducted using the Random, Google, and Alibaba benchmarks to compare several classic algorithms show that the proposed DDQN-TS can guarantee a high task completion rate and efficiently reduce the task average response time.

On Online Optimization: Dynamic Regret Analysis of Strongly Convex and Smooth Problems

The regret bound of dynamic online learning algorithms is often expressed in terms of the variation in the function sequence (V_T) and/or the path-length of the minimizer sequence after T rounds. For strongly convex and smooth functions, Zhang et al. (2017) establish the squared path-length of the minimizer sequence (C*_{2,T}) as a lower bound on regret. They also show that online gradient descent (OGD) achieves this lower bound using multiple gradient queries per round. In this paper, we focus on unconstrained online optimization. We first show that a preconditioned variant of OGD achieves O(min{C*_T,C*_{2,T}}) with one gradient query per round (C*_T refers to the normal path-length). We then propose online optimistic Newton (OON) method for the case when the first and second order information of the function sequence is predictable. The regret bound of OON is captured via the quartic path-length of the minimizer sequence (C*_{4,T}), which can be much smaller than C*_{2,T}. We finally show that by using multiple gradients for OGD, we can achieve an upper bound of O(min{C*_{2,T},V_T}) on regret.