کارابرن عزیز، مقالات isi بالاترین کیفیت ترجمه را دارند، ترجمه آنها کامل و دقیق می باشد (محتوای جداول و شکل های نیز ترجمه شده اند) و از بهترین مجلات isi انتخاب گردیده اند. همچنین تمامی ترجمه ها دارای ضمانت کیفیت بوده و در صورت عدم رضایت کاربر مبلغ عینا عودت داده خواهد شد.
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Prediction-based protocols for vehicular Ad Hoc Networks: Survey and taxonomy
پروتکل های مبتنی بر پش بینی برای شبکه های تک کاره وسیله ای: بررسی و طبقه بندی-2018
The high mobility of vehicles as a major characteristic of Vehicular Ad Hoc Networks (VANETs) affects vividly the dynamic nature of the networks and results in additional overhead in terms of extra messages and time delay. The future movements of the vehicles are usually predictable. The predictability of the vehicles future movements is a result of the traffic conditions, the urban layout, and the driving requirements to observe the traffic constrains. Hence, predicting these future movements could play a considerable role for both building reliable vehicular communication protocols and solving several issues of intelligent transportation systems. In the literature, numerous prediction-based protocols are presented for VANETs. Therefore, this paper follows the guidelines of systematic literature reviews to provide a premier and unbiased survey of the existing prediction-based protocols and develop novel taxonomies of those protocols based on their main prediction applications and objectives. A discussion on each category of both taxonomies is presented, with a focus on the requirements, constrains, and challenges. Moreover, usage analysis and performance comparisons are investigated in order to derive the suitability of each prediction objective to the various applications. Also, the relevant challenges and open research areas are identified to guide the potential new directions of prediction-based research in VANETs. Throughout this paper, information is provided to developers and researchers to grasp the major contributions and challenges of the predictive protocols in order to pave the way for enhancing their reliability and robustness in VANETs.
keywords: Prediction Applications| Prediction Objectives| Prediction Techniques| Research| VANETs
Simulation methodology and performance analysis of network coding based transport protocol in wireless big data networks
روش شبیه سازی و تجزیه و تحلیل کارایی پروتکل انتقال مبتنی بر کدگذاری شبکه در شبکه های داده های بزرگ بی سیم-2018
The Multi-Path, Multi-Hop (MPMH) communications have been extensively used in wire less network. It is especially suitable to big data transmissions due to its high throughput. To provide congestion and end-to-end reliability control, two types of transport layer pro tocols have been proposed in the literature: the TCP-based protocols and the rateless cod ing based protocols. However, the former is too conservative to explore the capacity of the MPMH networks, and the latter is too aggressive in filling up the communication capac ity and performs poorly when dealing with congestions. To overcome their drawbacks, a novel network coding scheme, namely, Adjustable Batching Coding (ABC), was proposed by us, which uses redundancy coding to overcome random loss and uses retransmissions and window size shrink to relieve congestion. The stratified congestion control strategy makes the ABC scheme especially suitable for big data transmissions. However, there is no simu lation platform built so far that can accurately test the performance of the network coding based transport protocols. We have built a modular, easy-to-customize simulation system based on an event-based programming method, which can simulate the ABC-based MPMH transport layer behaviors. Using the proposed simulator, the optimal parameters of the protocol can be fine-tuned, and the performance is superior to other transport layer pro tocols under the same settings. Furthermore, the proposed simulation methodology can be easily extended to other variants of MPMH communication systems by adjusting the ABC parameters.
Keywords: Network simulator ، Wireless big data networks ، Multi-path multi-hop communications ، Transport layer ، Network coding
Will aging voting machines cause more voters to experience long waits?
آیا پیرشدگی ماشین های رای گیری باعث خواهد شد تا رای دهنده های بیشتری انتظارات طولانی را تجربه کنند؟-2018
As the majority of voting machines in use today approach or exceed their expected lifetime, an increased number of voting machine failures are expected in upcoming elections. This study examines and quantifies the impact of less reliable voting machines, due to age, on the number of voters waiting longer than 30-min. G/G/s queue approximation and discrete event simulation are used in the analysis. Results show that if reliability measures — mean time between failures, mean time to repair, and availability — are within certain interval ranges, no additional voting machines are needed to ensure that no more than 5% of voters wait for longer than 30 min. However, significantly more voters would have long waits if the reliability of voting machines is poor. Accordingly, less reliable voting machines do not necessarily cause more voters to experience long waits. The proposed closed-form approximation formula and the simulation model are practical tools for election officials to evaluate the impact of less reliable voting machines on voting lines.
keywords: Voting operations |Simulation |Machine failure |Voting lines |Wait time distribution
Prediction Method for Smart Meter Life Based On Big Data
روش پیش بینی برای زندگی هوشمند متر بر اساس داده های بزرگ-2018
In order to better investigate the working life of Smart Meter and discover in advance the possible faults existed in the same batch, the operational data of Smart Meter in running state has to be analyzed so as to construct the prediction model of Smart Meter life. Firstly, we collect all the data from the running smart meters regarding the operational faults, maintenance management, and their application data from the Power Information Collection System; Secondly, we analyze the operational data in running state; Lastly, according to the advantages and disadvantages of the three reliability prediction methods (element stress method, reliability prediction method based on reliability test, and reliability prediction method based on reliability verification), we can protract the model that can reflect the life degradation characteristics and life prediction of smart meter.
Keywords: smart meter, reliability prediction technology, big data
Conception and Exploration of Using Data as a Service in Tunnel Construction with the NATM
مفهوم و اکتشاف استفاده از داده ها به عنوان یک سرویس در ساخت تونل با NATM-2018
The New Austrian Tunneling Method (NATM) has been widely used in the construction of mountain tun nels, urban metro lines, underground storage tanks, underground power houses, mining roadways, and so on. The variation patterns of advance geological prediction data, stress–strain data of supporting struc tures, and deformation data of the surrounding rock are vitally important in assessing the rationality and reliability of construction schemes, and provide essential information to ensure the safety and scheduling of tunnel construction. However, as the quantity of these data increases significantly, the uncertainty and discreteness of the mass data make it extremely difficult to produce a reasonable con struction scheme; they also reduce the forecast accuracy of accidents and dangerous situations, creating huge challenges in tunnel construction safety. In order to solve this problem, a novel data service system is proposed that uses data-association technology and the NATM, with the support of a big data environ ment. This system can integrate data resources from distributed monitoring sensors during the construc tion process, and then identify associations and build relations among data resources under the same construction conditions. These data associations and relations are then stored in a data pool. With the development and supplementation of the data pool, similar relations can then be used under similar con ditions, in order to provide data references for construction schematic designs and resource allocation. The proposed data service system also provides valuable guidance for the construction of similar projects.
Keywords: New Austrian Tunneling Method ، Big data environments ، Data as a service ، Tunnel construction
Correlation between strategic and operational risk mitigation strategies in supply networks
همبستگی بین راهبردهای کاهش خطر عملیاتی در شبکه های تامین-2018
A supply networks performance is affected by two types of risk: 1) risk of disruptions that distort the supply networks topology by inactivating certain production facilities or transportation lanes; and 2) risk of variations in a facilitys performance that reduce the efficiency of the supply networks flow planning for fulfilling demands. In this paper, we demonstrate that strategic and operational risk mitigation strategies, which neutralize the impacts of disruptions and variations, respectively, are correlated. We consider “Robustness” and “Resilience” at a strategic level to mitigate disruptions and “Reliability” at an operational level to mitigate variations. A mixed integer stochastic mathematical model is developed to simultaneously a) design a robust and resilient topology for supply networks; and b) plan a reliable flow throughout its topology. We solve the model using an example of a profit-based supply network that is constructed by relying on the assumptions that were primarily used in prior studies. A sensitivity analysis of the results from the model indicates that i) the correlation between robustness and resilience is negative; ii) the correlation between robustness and reliability is positive; and iii) the correlation between resilience and reliability is negative.
keywords: Supply network |Robust design |Disruption |Variation |Reliability |Resilience |Flexibility
تحقیق در مورد استراتژی توقف اطلاعات شبکه اجتماعی بر اساس ایزوله سازی موثر
سال انتشار: 2018 - تعداد صفحات فایل pdf انگلیسی: 8 - تعداد صفحات فایل doc فارسی: 15
در شبکه اجتماعی، استراتژی انزوا به طور وسیع زمانی پذیرفته می شود که ویروس شایع شود. با این حال، مشکل ایزوله¬سازی نامعتبر اغلب در این استراتژی وجود دارد، و در این فرآیند، گره ها همیشه تحرک را حفظ می کنند. به منظور حل این مشکلات، مدل SIQR بهبود یافته است، برخی از پارامترهای جدیدی مانند نرخ ورود جدید، نرخ خروج مستقل و نرخ جداسازی نامعتبر معرفی شد و وجود و پایداری نقطه ی تعادل با استفاده از نظریه میدان متوسط شبکه پیچیده مورد مطالعه قرار گرفت. ارتباط بین نرخ انتقال و نرخ انزوای ویروس نشان داده شد. قابلیت اطمینان از طریق آزمایش ها تایید شد. نتایج تجربی نشان داد که انتشار ویروس دارای یک آستانه است و نرخ انزوا در این آستانه منفی است. هنگامی که این ویروس شایع شد، با توجه به رابطه بین عوامل تاثیر گذار و آستانه، اقدامات موثر مختلفی برای کنترل انتشار آن به حداقل محدوده انتخاب شود.
واژه های کلیدی: مدل SIQR بهبود یافته | نظریه ميدان متوسط | نقطه تعادل | اقدامات موثر
|مقاله ترجمه شده|
Subcontracting strategies with production and maintenance policies for a manufacturing system subject to progressive deterioration
راهبردهای قرارداد فرعی با تولید و سیاست های حفظ برای یک سیستم ساخت و تولید قرار گرفته در معرض تباهی رو به پیشرفت-2018
This paper investigates the case of a manufacturing system subject to several progressive deterioration processes through an integrated model that seeks to determine the subcontracting, production and maintenance strategies employed simultaneously. The model is based on the premise that such deterioration affects several performance indices of the machine, centered mainly on the quality of the parts produced and on its reliability. When a machine fails, a minimal repair is conducted and preventive maintenance is available to restore the machine to initial conditions. The control policies indicate the production and preventive maintenance rates, as well as the amount of subcontracting required as a support measure to satisfy product demand. The main objective of the model is to minimize the discounted overall cost, which comprises production, subcontracting, inventory, backlog, preventive maintenance, defectives and repair costs. Hence, we develop a stochastic optimal control model, and numerical methods are used to solve optimality conditions in order to define the structure of the control policies. A simulation-based approach comprising statistical analysis and optimization techniques is applied to determine the optimal parameters associated with the structure of the control policies. The results obtained highlight the strong relations between production, maintenance, deterioration, reliability and quality, which justify the development of an integrated model. Through a numerical example and an extensive sensitivity analysis, we validate our approach.
keywords: Production planning |Subcontracting |Preventive maintenance |Quality deterioration |Reliability deterioration |Simulation
Implementation fidelity in computerised assessment of book reading
صحت اجرا در بررسی رایانه ای خواندن کتاب-2018
Measuring the implementation fidelity (IF) or integrity of interventions is extremely important, since without it a positive or negative outcome cannot be interpreted. However, IF is actually measured relatively rarely. Direct and indirect methods of measurement have been used in the past, but tend to over-emphasize teacher behaviour. This paper focuses on student behaviour collated through computers - an interesting alternative. It deals with the reading of real books and reading achievement, for which variables a very large amount of computerised data was available – on 852,295 students in 3243 schools. Reading achievement was measured pre-post with STAR Reading, a computerised item-banked adaptive norm-referenced test of reading comprehension. IF came from the Accelerated Reader (AR), which measures understanding of independent reading of real books the student has chosen by a quiz. Results showed higher IF was related to higher achievement. Neither IF nor reading achievement related to socio-economic status. Primary (elementary) schools had higher IF and achievement than secondary (high) schools. Females had higher IF and achievement than males. Students of higher reading ability implemented AR at a higher level, but did not gain in reading at a higher level. However, this computerised method of measuring IF with book reading showed limited reliability, no greater than methods emphasising teacher behaviour. In future, IF measures emphasising student response and those emphasising teacher behaviour need to be blended, although the latter will never generate the sample size of the former. This may be true of implementation fidelity in areas other than book reading.
keywords: Evaluation methodologies| Gender studies| Improving classroom teaching| Pedagogical issues| Teaching and learning strategies
Group technology: Amalgamation with design of organisational structures
فناوری گروهی: آمیختگی با طراحی ساختارهای سازمانی-2018
Group technology has been studied extensively from an ‘industrial engineering’ perspective (layout, scheduling, workflow, etc.), but less often from an organisational design viewpoint. To study this implication of group technology, the approach of applied systems theory for the design of organisational structures was used as framework for analysis in three empirical cases. To increase the reliability of findings from the analysis of these three empirical cases, five more cases were drawn from archival search. Cluster analysis and product flow analysis were the methods used for forming groups of machines and employees in manufacturing cells, whereas the coding of parts was not employed to this end. Furthermore, the results indicate that the implementation of group technology generally meets shifts in performance requirements caused by competitive pressures, particularly flexibility and responsiveness, albeit the companies considered group technology only when under pressure of ‘poor’ business performance. However, group technology is not always a solution to challenges that companies experience; one empirical case shows that defunctionalisation and scheduling with virtual groups was more beneficial. Nevertheless, when the introduction of group technology is feasible, it also allows firms to consider delegating responsibility for production planning and scheduling to lower levels in the hierarchy and semi-autonomous groups as an alternative to ‘complex’ software applications (a socio-technical approach). Whereas the current study sheds light on the relationship between group technology and design of organisational structures, further research is necessary into the design of these structures and their relationship to group technology.
keywords: Applied systems theory |Case studies |Cluster analysis |Flexibility |Group technology |Organisational design