Vitis: A Gossip-based Hybrid Overlay for Internet-scale Publish/Subscribe

Peer-to-peer overlay networks are attractive solutions for building Internet-scale publish/subscribe systems. However, scalability comes with a cost: a message published on a certain topic often needs to traverse a large number of uninterested (unsubscribed) nodes before reaching all its subscribers. This might sharply increase resource consumption for such relay nodes (in terms of bandwidth transmission cost, CPU, etc) and could ultimately lead to rapid deterioration of the system’s performance once the relay nodes start dropping the messages or choose to permanently abandon the system. In this paper, we introduce Vitis, a gossip-based publish/subscribe system that significantly decreases the number of relay messages, and scales to an unbounded number of nodes and topics. This is achieved by the novel approach of enabling rendezvous routing on unstructured overlays. We construct a hybrid system by injecting structure into an otherwise unstructured network. The resulting structure resembles a navigable small-world network, which spans along clusters of nodes that have similar subscriptions. The properties of such an overlay make it an ideal platform for efficient data dissemination in large-scale systems. We perform extensive simulations and evaluate Vitis by comparing its performance against two base-line publish/subscribe systems: one that is oblivious to node subscriptions, and another that exploits the subscription similarities. Our measurements show that Vitis significantly outperforms the base-line solutions on various subscription and churn scenarios, from both synthetic models and real-world traces

Correlation between expression levels of mRNA IL-6 and H. pylori-infected patients with cagA

خلاصه سابقه و هدف: عفونت هلیکوباکترپیلوری با جذب سلول‌های التهابی مانند نوتروفیل، ماکروفاژ و سلول‌های T و B اختصاصی هلیکوباکتری به ناحیه درگیر عفونت همراه می‌باشد. مسیرهای مولکولی کنترل پاسخ ایمنی بر علیه این باکتری خیلی پیچیده می باشد، اما معمولاً سایتوکاین‌های که در ناحیه درگیر عفونت تولید می‌شوند در حفظ و گسترش عفونت نقش دارند. هدف از این مطالعه بررسی بیان ژن IL-6 در سطح مخاط بیماران آلوده به هلیکوباکترپیلوری و غیرآلوده و همچنین ارتباط آن با فاکتور ویرولانس cagA در میان افراد آلوده به هلیکوباکترپیلوی می‌باشد مواد و روش ها: این مطالعه از نوع موردی- شاهدی می‌باشد. از 58 نفر از مبتلایان به هلیکوباکترپیلوری و 44 نفر از افرادی که آلوده به این باکتری نبودند توسط آندوسکوپی بیوپسی تهیه شد. و بعد از استخراجmRNA ، توسط real-time PCR، میزان بیانmRNA IL-6 اندازه گیری شد. فاکتور بیماری زای cagA توسط PCR ارزیابی شد. بیان سایتوکاین ها در دو گروه آلوده و غیرآلوده با استفاده از تست T-Test مورد آنالیز قرار گرفتند. یافته ها: سطح بیان IL-6 mRNA در بیماران دارای هلیکوباکترپیلوری نسبت به افراد غیرآلوده به بطور معنی داری بالاتر می‌باشد. ارتباط معنی‌داری بین فاکتور بیماری‌زای cagA و سطح بیان IL-6 mRNA مشاهده نشد. نتیجه گیری: افزایش بیان IL-6 mRNA ممکن است مستقل از فاکتور ویرولانس cagA و در ایجاد التهاب معده همراه با هلیکوباکترپیلوری نقش مهمی داشته باشد

Vinifera: A Gossip-based Hybrid Overlay for Content-based Publish/Subscribe

CN

Variable weight spectral amplitude coding for multiservice OCDMA networks

The emergence of heterogeneous applications such as internet data, video streaming, and online gaming, brings in a demand for a network environ- ments with capability of supporting diverse Quality of Services (QoS). Prioritizing the services is essential to ensure the delivery of information is at their best. This paper proposes a new code family to support optical domain service differentiation using spectral amplitude coding techniques within an optical code division multiple access (OCDMA) scenario. A particular user or service has a varying weight applied in order to obtain the desired signal quality. The proposed variable-weight code (VW-code) is constructed based on basic multi-service (MS) code. Mathematical model is developed to for performance evaluation of VW-MS code. In addition, the properties of pro- posed code is compared with other VW-OCDMA codes. It is shown that the proposed VW-MS provide an optimal code length with minimum cross- correlation compared to other VW-codes. Performance of VW-MS designed for triple-play services operating at bit rates of 0.622, 1.25 and 2.5 Gbps is demonstrated

Nutrient use efficiency and nutrient uptake promoting of rice by potassium solubilizing bacteria (KSB)

The current study was carried out in both pot and field conditions to investigate the effects of three KSB strains of Pantoea agglomerans, Rahnella aquatilis and Pseudomonas orientalis on nitrogen (N), phosphorous (P) and potassium (K) uptake, nutrient use efficiency parameters and nutrients remobilization in rice (Oryza sativa L. cv. Pajohesh). The experiments included 15 treatments of KSB inoculations, commercial K biofertilizer and K chemical fertilizer. The results showed that the inoculums of all three KSB strains increased the K, N and P uptake by grain and straw, especially when applied in combination with ½ K chemical fertilizer (47.5 Kg/ha) as compared to the control treatment. The highest value of available K in the soil obtained from NPK chemical fertilizer equal to 140.1 and 134.6 mg K per kg of soil in the pot and field experiments, respectively, which were significantly higher than KSB inoculations treatments. Bacterial inoculums coupled with ½ K chemical fertilizer also enhanced the nutrient use efficiency (including agronomic efficiency (AE), apparent recovery efficiency (ARE), physiological efficiency (PE), agro-physiological efficiency (APE), internal utilization efficiency (UE), partial factor productivity (PFP), partial nutrient balance (PNB)) and nutrient remobilization. The results indicated that the bioinoculation with these KSB strains isolated from soil paddy could be considered as an effective way to increase potassium, nitrogen and phosphorus uptake by rice plant and enhance their use efficiency and remobilization to grains in the flooding irrigation conditions

Health monitoring of civil infrastructures by subspace system identification method: an overview

Structural health monitoring (SHM) is the main contributor of the future's smart city to deal with the need for safety, lower maintenance costs, and reliable condition assessment of structures. Among the algorithms used for SHM to identify the system parameters of structures, subspace system identification (SSI) is a reliable method in the time-domain that takes advantages of using extended observability matrices. Considerable numbers of studies have specifically concentrated on practical applications of SSI in recent years. To the best of author's knowledge, no study has been undertaken to review and investigate the application of SSI in the monitoring of civil engineering structures. This paper aims to review studies that have used the SSI algorithm for the damage identification and modal analysis of structures. The fundamental focus is on data-driven and covariance-driven SSI algorithms. In this review, we consider the subspace algorithm to resolve the problem of a real-world application for SHM. With regard to performance, a comparison between SSI and other methods is provided in order to investigate its advantages and disadvantages. The applied methods of SHM in civil engineering structures are categorized into three classes, from simple one-dimensional (1D) to very complex structures, and the detectability of the SSI for different damage scenarios are reported. Finally, the available software incorporating SSI as their system identification technique are investigated

Exploring the impacts of using Geogebra software on secondary school students’ misconceptions in trigonometric functions

Background and Objectives: Previous studies in Iran have explored the impact of using technology on improving students’ mathematical understanding. However, no study was conducted in relation to the impact of using technology on students’ mathematical misconceptions. This study explored the impact of using software in developing students’ misconceptions. In detail, the impact of using GeoGebra software on secondary school students’ misconceptions related to concepts such as angle scale, trigonometric angles, periodicity, minimum and maximum of trigonometric functions were explored using a two-tier diagnostic test. One of the novelties of this study is the use of a two-tier diagnostic test to explore misconceptions resulting from using the software. Methods: The statistical population of this study comprises all grade 11 students of Golbahar and Golmakan in the academic year 2015-2016. Three classes were chosen from two different schools in these cities, one was considered as the control group (40 students) and the other two classes were considered as the experimental group (26 students). The instruments were a pre-test and a post-test (two-tier diagnostic test).‎ Four categories of misconceptions were identified based on the relevant literature and students’ responses to the pre-test. Finally, these misconceptions were analyzed by the chi-square test. Findings: The findings showed that Geogebra software helped students in the experimental group enormously in understanding concepts such as periodicity‎, ‎identifying minimum and maximum of trigonometric functions‎, ‎and prevented developing misconceptions related to them. Analyzing students’ responses in the control group that received traditional teaching showed that several students did not able to calculate the periodicity of trigonometric functions. This difficulty observed both when students calculated the periodicity from the graphs and also when calculated the periodicity from the algebraic form of trigonometric functions. The strength of using the software includes observing many trigonometric graphs in the software environment, the ability to place trigonometric functions with different input on a coordinate axis and comparing them, and the manipulations performed by the students themselves on trigonometric graphs. These strengths prevented students from developing misconceptions about the concepts of frequency and minimum and maximum values. However, in relation to trigonometric angles‎, ‎using the software caused developing more misconceptions for the test group, and had no significant impact on preventing misconceptions in relation to the scale of angle‎. It seems due to the nature of the angle scale, in which the conversion from radians to degrees (or vice versa) is done by a series of mathematical operations, using Geogebra could not impact students’ misconceptions in this matter. Conclusion: The results of this study indicate that teachers should be very cautious in selecting and using teaching aids in the classroom to prevent developing mathematical misconceptions associated with using the teaching aids. Therefore, we recommend mathematics education researchers and mathematics curriculum planners to conduct several studies on different softwares frequently used in mathematics classes, determine the pros and cons of these tools, and share their results with mathematics teachers. Sharing these results will help mathematics teachers to adapt their teaching accordingly based on the findings of these studies.   ===================================================================================== COPYRIGHTS  ©2020 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.  ====================================================================================

A Distributed Algorithm For Large-Scale Graph Partitioning

Detta kandidatarbete har sin placering på Skeppsbron/Skeppsbrokajen i centrala Stockholm. Inriktningen jag valde var att rita ett förslag för en fiskmarknad som skulle placeras på denna plats. Mitt arbete har fått inspireras av Sveriges största och mest kända fiskmarknad, Feskekörkan, i Göteborg. Analyser av Feskekörkan som organisation och dess planlösning har i mitt arbete lett till en tektoniskt uppbyggd struktur där material byggnadskonstruktion var viktiga element. Med bland annat en fiskfjällsfasad i mässing och en bärande skelett av storskaliga limträbalkar. Platsen som byggnaden ligger på är ett välbesökt promenadstråk med en bred och lång kajkant som används flitigt av såväl, turister som besöker gamla stan och det kungliga slottet, och Stockholmare som tar sig mellan Södermalm och Norrmalm. Jag har valt att bebygga platsen på ett sätt som både tar vara på det vackra promenadstråket men också ger möjlighet för besökande att stanna upp och ta del av fiskmarknaden.This candidate's work has its placement on Skeppsbron/Skeppsbrokajen in the central area of Stockholm. The focus I chose was to draw a proposal for a fishmarket that would be placed at this location. My work has been inspired by the largest and most famous fish market in Sweden, Feskekörkan, in Gothenburg. Analyses of Feskekörkan’s organization and its plan has, in my work, led to a tectonically constructed structure where building materials were important elements. Including a fish scale facade made of brass and a bearing skeleton of large glulam beams. The place which the building is situated on a popular promenade with a broad and long quay which is widely used by both, tourists visiting the Old Town and the Royal Palace, and the Stockholm citizens who ride between Södermalm and Norrmalm. I have chosen to build on the site in a way that both takes advantage of the beautiful promenade but also provides the opportunity for visitors to stop and take some of the fish market

A novel semi-active TMD with folding variable stiffness spring

An innovative variable stiffness device is proposed and investigated based on numerical simulations. The device, called a folding variable stiffness spring (FVSS), can be widely used, especially in tuned mass dampers (TMDs) with adaptive stiffness. An important characteristic of FVSS is its capability to change the stiffness between lower and upper bounds through a small change of distance between its supports. This special feature results in lower time-lag errors and readjustment in shorter time intervals. The governing equations of the device are derived and simplified for a symmetrical FVSS with similar elements. This device is then used to control a single-degree-of-freedom (SDOF) structure as well as a multi-degree-of-freedom (MDOF) structure via a semi-active TMD. Numerical simulations are conducted to compare several control cases for these structures. To make it more realistic, a real direct current motor with its own limitations is simulated in addition to an ideal control case with no limitations and both the results are compared. It is shown that the proposed device can be effectively used to suppress undesirable vibrations of a structure and considerably improves the performance of the controller compared to a passive device