varunr14/newsummary huggingface dataset:
Online social networking websites such as Twitter and Facebook are known to have a wide heterogeneity in the popularity of their users which is counted typically in terms of the number of followers or friends of the users . We add to the large body of work on information diffusion on online social networking websites by studying how the behavior of the small minority of very popular users on Twitter differs from that of the bulk of the population of ordinary users and how these differences may impact information diffusion . Our findings are somewhat counter intuitive . We find that on aggregate metrics such as the tweeting volume and degree of participation on different topics popular users and ordinary users seem similar to each other . We also find that although popular users do seem to command an influential position in driving the popularity of topics on Twitter in practice they do not affect growth rates of user participation and the causality of popular users driving event popularity is hard to establish . Our observations corroborate the findings of other researchers who show that user popularity in terms of number of followers does not translate into driving event popularity but that event popularity may be driven by extraneous factors to do with the importance of the event . 


Summary: Popular users tweet slightly earlier than ordinary users during the growth of Twitter events Popular users engage with a Twitter event for slightly longer than ordinary users Popular users write more original tweets than retweets while the trend is the reverse for ordinary users Tweets by popular users are retweeted more than tweets by ordinary users Popular users are the quickest to retweet tweets The volume of tweeting by popular users is however not different from that of ordinary users Popular users also do not seem to have an influence on the event growth rates Eventual popularity attained by an event is positively correlated with participation by popular users but causality is hard to establish
Blue color organic polymeric light emitting diodes are very important because they can be used for tri color display applications fluorescence imaging and exciting yellow phosphor for generating white light for general illumination . But the efficiency of blue organic polymeric light emitting diodes is considerably low due to their large band gap that requires higher energy for effective emission . In this paper we report the enhancement in polyfluorene blue organic light emitting diodes with a polymer nano composite hole transport layer . Blue light emitting diode based on polyfluorene as an emissive layer and poly poly titanium dioxide nanocomposite as the hole transport layer were fabricated and studied . Different concentrations of titanium dioxide nanoparticles were doped in poly poly in the hole transport layer and the performance of the devices were studied . Significant enhancement in the blue peak at 430nm of polyfluorene has been observed with increase in concentration of TiO2 nanoparticles in the hole transport layer . The turn on voltage of the device has also been found to improve significantly with the incorporation of titanium dioxide nanoparticles in the hole transport layer . The optimized concentration of titanium dioxide in the hole transport layer for most efficient device has been found to 15wt . . 


Summary: Polyfluorene based blue OLEDs with polymer nano composite HTL have been fabricated. Significant enhancement in blue peak at 430nm of polyfluorene has been observed. The turn on voltage of the device has also been found to improve significantly. The concentration of TiO2 nanoparticles in the HTL has been optimized.
Root cause analysis is a recommended practice in retrospectives and cause effect diagram is a commonly recommended technique for RCA . Our objective is to evaluate whether CED improves the outcome and perceived utility of RCA . We conducted a controlled experiment with 11 student software project teams by using a single factor paired design resulting in a total of 22 experimental units . Two visualization techniques of underlying causes were compared CED and a structural list of causes . We used the output of RCA questionnaires and group interviews to compare the two techniques . In our results CED increased the total number of detected causes . CED also increased the links between causes thus suggesting more structured analysis of problems . Furthermore the participants perceived that CED improved organizing and outlining the detected causes . The implication of our results is that using CED in the RCA of retrospectives is recommended yet not mandatory as the groups also performed well with the structural list . In addition to increased number of detected causes CED is visually more attractive and preferred by retrospective participants even though it is somewhat harder to read and requires specific software tools . 


Summary: Root cause analysis is a recommended practice in retrospectives. We compare the use of cause effect diagram to the use of structural lists in root cause analysis. Cause effect diagram improves the root cause analysis. Cause effect diagram is preferred by participants 75 .
Smart grid combines a set of functionalities that can only be achieved through ubiquitous sensing and communication across the electrical grid . The communication infrastructure must be able to cope with an increasing number of traffic types which is as a result of increased control and monitoring penetration of renewable energy sources and adoption of electric vehicles . The communication infrastructure must serve as a substrate that supports different traffic requirements such as QoS across an integrated communication system . This engenders the implementation of middleware systems which considers QoS requirements for different types of traffic in order to allow prompt delivery of these traffic in a smart grid system . A heterogeneous communication applied through the adaptation of the Ubiquitous Sensor Network layered structure to smart grid has been proposed by the International Telecommunication Union . This paper explores the ITU s USN architecture and presents the communication technologies which can be deployed within the USN schematic layers for a secure and resilient communication together with a study of their pro s and con s vulnerabilities and challenges . It also discusses the factors that can affect the selection of communication technologies and suggests possible communications technologies at different USN layers . Furthermore the paper highlights the USN middleware system as an important mechanism to tackle scalability and interoperability problems as well as shield the communication complexities and heterogeneity of smart grid . 


Summary: We explored the adaptation of the USN architecture for SG communication. We reviewed existing communication technologies that can be deployed in SG USN. Vulnerability and challenges of the USN architecture for SG were highlighted. The choice of communication technologies reduces complexity in SG communication. A secure and QoS aware USN middleware can guarantee requirements of SG application.
This paper presents an approach for the automated debugging of reactive and concurrent Java programs combining model checking and runtime monitoring . Runtime monitoring is used to transform the Java execution traces into the input for the model checker the purpose of which is twofold . First it checks these execution traces against properties written in linear temporal logic which represent desirable or undesirable behaviors . Second it produces several execution traces for a single Java program by generating test inputs and exploring different schedulings in multithreaded programs . As state explosion is the main drawback to model checking we propose two abstraction approaches to reduce the memory requirements when storing Java states . We also present the formal framework to clarify which kinds of LTL safety and liveness formulas can be correctly analysed with each abstraction for both finite and infinite program executions . A major advantage of our approach comes from the model checker which stores the trace of each failed execution allowing the programmer to replay these executions to locate the bugs . Our current implementation the tool TJT uses Spin as the model checker and the Java Debug Interface for runtime monitoring . TJT is presented as an Eclipse plug in and it has been successfully applied to debug complex public Java programs . 


Summary: We use linear time temporal logic to represent both failures and desirable behaviors regarding a temporally ordered sequence of events and or conditions to be checked along one execution. We use model checking algorithms record the history of the failed execution which we use to implement a controlled replay to locate the bugs. We support the analysis of potentially infinite executions. We use runtime techniques to start the debugging work directly on the programmer s code.
This work presents the possibility of the hollow core nanoparticles to improve luminance in an organic light emitting diode device . The finite difference time domain simulation estimates the effect of the hollow core nanoparticles on the external quantum efficiency of the organic light emitting diode device . The efficiency depends on the size and the volume fraction of the hollow core nanoparticles in the polymer layer together with the refractive index and the thickness of the polymer layer . It is shown that the hollow core nanoparticles dispersed in a polymer layer can enhance the external quantum efficiency by a factor of 2.5 . This work also introduces a continuous production method of the hollow core nanoparticles by using the microfluidic self assembly of amphiphilic polymers and the layer formation dispersed with them for the rigorous light scattering . 


Summary: The hollow core nanoparticles can improve the luminance of OLED. The HCNPs can enhance the external quantum efficiency by a factor of 2.5. The HCNPs have been produced continuously by using the microfluidic self assembly. The HCNPs dispersed polymer layer has been also demonstrated successfully.
We introduce a novel basis for multivariate hierarchical tensor product spline spaces . Our construction combines the truncation mechanism with the idea of decoupling basis functions . While the first mechanism ensures the partition of unity property which is essential for geometric modeling applications the idea of decoupling allows us to obtain a richer set of basis functions than previous approaches . Consequently we can guarantee the completeness property of the novel basis for large classes of multi level spline spaces . In particular completeness is obtained for the multi level spline spaces defined on T meshes for hierarchical splines of degree p for example with single knots and p adic refinement and with knots of multiplicity and dyadic refinement without any further restriction on the mesh configuration . Both classes include multivariate quadratic hierarchical tensor splines with dyadic refinement . 


Summary: The paper introduces a novel basis for multivariate hierarchical tensor product spline spaces. It uses the truncation mechanism and the idea of decoupling. The truncation mechanism ensures the partition of unity property. The idea of decoupling allows us to obtain a richer set of basis functions than previous approaches. The construction guarantees the completeness property of the novel basis for large classes of multi level spline spaces.
Electrowetting display is a reflective display technology in which fluidic pixels can response and switch quickly by electronic control showing the capability for video speed reflective display applications . In this paper a new driver system is proposed and realized for video playing function of active matrix electrowetting display . The hardware system is designed based on Field Programmable Gate Array and the existing electrophoretic display driving integrated chips . A driving logic circuit and FPGA software is introduced for providing the EWD system with driving and timing control . And a set of specific driving waveforms which is loaded to a lookup table of the FPGA in advance is designed to display grayscale on EWDs . 4 level gray scale videos have been successfully performed by applying the driving waveforms . To our knowledge such work has not been reported before . 


Summary: A driver is designed for video playing in active matrix electrowetting displays. The hardware system is designed based on commercial driver integrated chips. A timing controller is designed in a FPGA according to the system characteristics. We design new driving waveforms for playing videos in electrowetting displays. The driving system could work very well for playing 4 gray scale video.
We consider isogeometric functions and their derivatives . Given a geometry mapping which is defined by an n dimensional NURBS patch in an isogeometric function is obtained by composing the inverse of the geometry mapping with a NURBS function in the parameter domain . Hence an isogeometric function can be represented by a NURBS parametrization of its graph . We take advantage of the projective representation of the NURBS patch as a B spline patch in homogeneous coordinates . We derive a closed form representation of the graph of a partial derivative of an isogeometric function . The derivative can be interpreted as an isogeometric function of higher degree and lower smoothness on the same piecewise rational geometry mapping hence the space of isogeometric functions is closed under differentiation . We distinguish the two cases and with a focus on in the latter one . As a first application of the presented formula we derive conditions which guarantee and smoothness for isogeometric functions on several singularly parametrized planar and volumetric domains as well as on embedded surfaces . It is interesting to note that the presented conditions depend not only on the general structure of the patch but on the exact representation of the interior of the given geometry mapping . 


Summary: We derive an exact representation of the derivatives of an isogeometric function. The isogeometric function is defined over a domain of arbitrary dimension. We use the formula to derive smoothness results for functions on singular patches. The conditions depend on the exact representation of the interior of the domain. The derivative formula can be used to derive functionals for regularization.
This paper presents a new three dimensional display that can display 3 D images at long distances of tens or hundreds of meters in the depth direction and that can control their 3 D positions to meet new requirements for outdoor use . The proposed display uses changing size as a cue to depth perception i.e . the smoothly expanding motion of virtual images formed with optical systems according to the forward movements of the users to display 3 D images at more distant positions in the depth direction than positions where virtual images are formed with optical systems because conventional 3 D displays that use binocular disparity are only able to display 3 D images at short distances in the depth direction . The feasibility of the proposed display was evaluated by subjective tests using a moving minivan in which observers viewed a test pattern that overlapped the real view ahead of the automobile observed through the windshield . The results obtained from the subjective tests revealed that the test pattern was observed at long distances over tens and hundreds of meters in the depth direction and that the position in the depth direction of the test pattern could be controlled by changing the rate at which the motion of the test pattern smoothly expanded . These results demonstrated that the proposed display was feasible . 


Summary: This study presents a new 3 D display that can display 3 D images in wide spaces. The 3 D positions of 3 D images displayed with the proposed display are controlled. The proposed display uses changing size as a cue to depth perception of 3 D images. The feasibility of the proposed display is evaluated with psychophysical experiments. The results of the experiments demonstrate that the proposed display is feasible.
A big portion of Internet traffic nowadays is video . A good understanding of user behavior in online Video on Demand systems can help us design configure and manage video content distribution . With the help of a major VoD service provider we conducted a detailed study of user behavior watching streamed videos over the Internet . We engineered the video player at the client side to collect user behavior reports for over 540 million sessions . In order to isolate the possible effect of session quality of experience on user behavior we use only the sessions with perfect QoE and leave out those sessions with QoE impairments . Our main finding is that users spend a lot of time browsing viewing part of one video after another and only occasionally watching a video to its completion . We consider seek as a special form of browsing repeating partial viewing of the same video . Our analysis leads to a user behavior model in which a user transitions through a random number of short views before a longer view and repeats the process a random number of times . This model can be considered an extension and a more detailed alternative to the closed queueing network formulation introduced by Wu et al . . As an application of our user behavior model we use it to measure video popularity . We study the similarity of our approach to subjective evaluation and simple view count based metric and conclude our approach gives results closer to subjective evaluation . 


Summary: We discover a quite consistent user early departure pattern for different sets of view records over different time periods for videos of different popularity. We show the distribution of the number of videos a user transition through. This understanding helps construct a more realistic user behavior model. We show seeks can be considered as part of video browsing and explain what users are doing using seek either emulating fast forwarding or looking for some specific content. We measure a user level video switching and early departure behavior. We explore the online video popularity and users seek behavior.
Computing paradigms have shifted towards highly parallel processing and massive replication of data . This entails the efficient distribution of requests and the synchronization of results provided to users . Guaranteeing SLAs requires the ability to evaluate the performance of such systems while taking the effect of non parallel workloads into consideration . This can be achieved with performance models that are able to represent both parallel and sequential workloads . This paper presents a product form stochastic Petri net approximation of fork join queueing networks with interfering requests . We derive the necessary conditions that guarantee the accuracy of the approximations and verify this through examples in comparison to simulation . We apply these approximate models to the performance evaluation of replication in NoSQL cloud datastores and illustrate the composition of large models from smaller models thus facilitating the ability to model a range of deployment scenarios . We show the efficiency of our solution method which finds the product form solution of the models without the representation of the state space of the underlying CTMC . 


Summary: Product form SPN approximation for fork join networks with interfering requests. Conditions for accurate approximation. Validation against simulation. Evaluation of the performance of replication in NoSQL cloud datastores.
To obtain a black matrix with high optical density and low dielectric constant graphene oxide was prepared from synthetic graphite oxide and then incorporated into the conventional carbon black pigment to fabricate black matrix films . The introduction of insulating GO effectively lowered the dielectric constant of carbon black based BM but maintained the high optical density . The dielectric constant of the BM film significantly decreased from 26 to 4.5 . This work demonstrates the successful chemical modification and good dispersion of carbon based materials and their physical effects on the BM films . 


Summary: The introduction of insulating graphene oxide in carbon black containing black matrix. Effect of BYK2150 dispersant on dispersion of carbon based materials. Targeting low dielectric constant of the black matrix film while maintaining high optical density.
In this paper we propose a novel method for the blind compensation of drift for the asynchronous recording of an ad hoc microphone array . Digital signals simultaneously observed by different recording devices have drift of the time differences between the observation channels because of the sampling frequency mismatch among the devices . On the basis of a model in which the time difference is constant within each short time frame but varies in proportion to the central time of the frame the effect of the sampling frequency mismatch can be compensated in the short time Fourier transform domain by a linear phase shift . By assuming that the sources are motionless and have stationary amplitudes the observation is regarded as being stationary when drift does not occur . Thus we formulate a likelihood to evaluate the stationarity in the STFT domain to evaluate the compensation of drift . The maximum likelihood estimation is obtained effectively by a golden section search . Using the estimated parameters we compensate the drift by STFT analysis with a noninteger frame shift . The effectiveness of the proposed blind drift compensation method is evaluated in an experiment in which artificial drift is generated . 


Summary: Modeling of drift as frame shift. STFT domain compensation as linear phase shift. Probabilistic model of drift. Maximum likelihood estimation of sampling frequency mismatch. Efficient resampling with modified STFT analysis with noninteger frame shift.
This work develops LED Light Emitting Diode image display system that can display patterns on the spokes of a bicycle. The proposed system of LED lights that are mounted on the wheel can provide safety by producing a beautiful pattern. The main control board and LED lighting strips that determine the displayed pattern are developed using embedded system and electrical circuit designs. A mobile application program is developed to control the lighting hardware remotely the system communicates with the main control board via a Wi Fi wireless network interface. The cyclist can change the patterns using the mobile application program or by pushing buttons on the main control board before riding. Six patterns are designed for display using this system and the pattern can be made to change repeatedly at present intervals. Experimental results reveal that the proposed system performs effectively on the wheel up to a maximum speed of 40 km hr. 


Summary: Three LED lighting strips perform the LED imaging function on the wheel. The LED lighting strip is controlled by the mobile APP via a Wi Fi wireless network. It can work normally with wheel speed up to 35km hr.
We demonstrated an optimized 8 domain vertical aligned liquid crystal display by minimizing its color washout . The index G is adopted to analyze the degree of color washout through simulation . By using linearly and circularly polarized incident light the optimized regime of the area and applied voltage ratios of sub pixels is obtained . In the experiments with the circularly polarized light the images are sensuously improved in a coupled capacity type LCD by applying the simulated applied voltage ratio of two sub pixels . 


Summary: We optimized an 8 domain VA LCD by minimizing its color washout. We adopted the index G value to analyze the degree of color washout. The color washout is improved in all the oblique viewing direction. In general the quality of LCD is raised.