scholarly journals Blind Corner Propagation Model for IEEE 802.11p Communication in Network Simulators

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Sanchai Jaktheerangkoon ◽  
Kulit Na Nakorn ◽  
Kultida Rojviboonchai
Keyword(s):  
Variable Parameter ◽  
Propagation Model ◽  
Experimental Results ◽  
Ieee 802.11P ◽  
Connected Vehicle ◽  
Road Transportation ◽  
The Real ◽  
Proposed Model ◽  
Network Simulators ◽  
The Impact

Vehicular Ad Hoc Network (VANET) has been developed to enhance quality of road transportation. The development of safety applications could reduce number of road accidents. IEEE 802.11p is a promising standard for intervehicular communication, which would enable the connected-vehicle applications. However, in the well-known network simulators such as NS3 and Omnet, there is no propagation model that can simulate the IEEE 802.11p communication at blind corner realistically. Thus, in this paper, we conducted the real-world experiments of IEEE 802.11p in order to construct the model to describe the characteristics of the IEEE 802.11p communication at the blind corners. According to the experimental results, we observe that the minimum distance between the vehicle and the corner can effectively be represented as the key parameter in the model. Moreover, we have a variable parameter for adjusting the impact of the obstruction which could be different at each type of blind corners. The simulation results using our proposed model are compared with those using the existing obstacle model. The results showed that our proposed model is much more closely aligned with the real experimental results.

scholarly journals Dimensional variability of orthodontic slots and archwires: an analysis of torque expression and clinical implications

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Michele Tepedino ◽  
Giordano Paiella ◽  
Maciej Iancu Potrubacz ◽  
Annalisa Monaco ◽  
Roberto Gatto ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Variable Parameter ◽  
Clinical Implications ◽  
Order Information ◽  
Third Order ◽  
The Real ◽  
Recorded Data ◽  
The Impact ◽  
One Way Anova ◽  
Production Tolerance

Abstract Background The loss of third-order information in pre-adjusted brackets due to torsional play is a problem in clinical orthodontics. The aim of this study was to evaluate the impact of slot height, archwire height, width and edge bevel’s radius on the torsional play for three brackets/archwire systems. Methods Ninety brackets with a 0.022 × 0.028 in. slot with McLaughlin-Bennett-Trevisi prescription from three different manufacturers were selected, and the slot’s height and depth were measured using a profile projector. Sixty stainless-steel rectangular archwires from three different manufacturers were sectioned and observed with a SEM to measure their height, width, and radius of edge bevel. The recorded data were used to calculate the theoretical torsional play between different slot−archwire combinations. One-way ANOVA was used to compare the measurements within different bracket types and among different manufacturers. Results Slot height was usually oversized. Archwire’s height was usually undersized, but oversized wires were also observed. The radius edge bevel was the most variable parameter. A certain degree of torsional play is always present that differs from one bracket type to another of the same producer and that can even be doubled from one manufacturer to another. Conclusions Due to production tolerance, differences between the nominal values and the real dimensions of any components of a slot/archwire system are common. This results in a torsional play that limits torque expression. The archwire’s edge bevel plays an important role in torque expression, and clearer information should be provided by the manufacturers regarding this aspect.

scholarly journals A System Dynamics Model of the Modal Shift from Road to Rail: Containerization and Imposition of Taxes

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Bulim Choi ◽  
Su-il Park ◽  
Kang-Dae Lee
Keyword(s):  
System Dynamics ◽  
Carbon Dioxide Emissions ◽  
System Dynamics Model ◽  
Road Transportation ◽  
Dynamics Model ◽  
Modal Shift ◽  
The Past ◽  
Proposed Model ◽  
Policy Measures ◽  
The Impact

Over the past decade, intermodal transport focused on reducing external cost, congestion, and carbon dioxide emissions, which have been caused by road transportation. Many policy measures for the modal shift from road to rail have been introduced to address these problems. This study aims at examining the impact of policy measures on promoting modal shift. In line with the previous research on modal shift, a system dynamics model, which can calculate both expected and real modal share, was developed. The proposed model was applied to the steel industry for steel rolled coils transport in South Korea. Under our analysis conditions, the modal shift by the containerization occurred more rapidly than taxations. The major contributions of this paper are as follows: (1) supporting the model to anticipate the modal shift from road to rail and (2) suggesting new insight to promote the modal shift using containerization.

scholarly journals Visual Description of the Indoor Space of Real Estate in Crowd-Sourcing Environments

2020 ◽  
Vol 28 (3) ◽  
pp. 91-103
Author(s):  
Sara Haghbayan ◽  
Mohammad Reza Malek ◽  
Behnam Tashayo
Keyword(s):  
Real Estate ◽  
Collective Intelligence ◽  
Crowd Sourcing ◽  
The Real ◽  
The Real Estate ◽  
Indoor Space ◽  
Collaborative Tools ◽  
Proposed Model ◽  
Sketch Plan ◽  
The Impact

AbstractEmerging the power of collective intelligence through crowdsourcing could create a clear path for visualizing real estate as well. One of the Crowdsourcing applications is describing the indoor space of a real estate. This paper aims to describe real estate in the context of spatial crowdsourcing. Qualitative and quantitative criteria were used in this study to describe the real estate space, topological relationships, directional relations, color, location, dimensions, and height as qualitative criteria. Quantitative criteria were selected as the dimensions and height. The proposed model was evaluated by two groups: those who had never seen the real estate and others that had already seen the same real estate. We implemented a website called SAMA1 to evaluate the proposed model with crowdsourcing data using online collaborative tools. SAMA is using tools, such as a sketch plan, photo, text, virtual tour, and visual descriptions. To evaluate SAMA, we compared it with four representative commercial websites, and the impact of the tools was precisely examined. The obtained results demonstrate that the proposed model can be utilized to visually describe the indoor space of real estate in crowd-sourcing environments.

scholarly journals Design and Analysis of an Efficient and Reliable Mac Protocol for Vanets

2021 ◽  
Author(s):  
Khalid Abdel Hafeez
Keyword(s):  
High Stability ◽  
Mac Protocol ◽  
Network Capacity ◽  
Wireless Channel ◽  
Propagation Model ◽  
Ieee 802.11P ◽  
Inference System ◽  
Hidden Terminal ◽  
On The Road ◽  
The Impact

The increase number of vehicles on roads and the immense number of fatal accidents they cause have driven the research and development of new generation technologies to help drivers travel more safely. One major cause of traffic accidents is that drivers cannot consistently respond to the changing road conditions appropriately. In fact, most accidents could be avoided if drivers could obtain and use relevant information of the traffic that is beyond their vision using wireless communications technology. Recently, the IEEE community adopted the IEEE 802.11p standard as a main technology for VANETs. To test the feasibility of this technology, most researchers use simulations to evaluate its new applications and protocols due to the prohibitive cost of implementing real VANET setup. Therefore, we first analyze VANET’s wireless channel analytically and by simulations to predict its most appropriate propagation model and the communication range that minimizes the impact of the hidden terminal problem. Second, we derive a new mobility model that takes into account the vehicle’s follow-on safety rule, to accurately derive the relationship between vehicle’s speed and network density. It is expected that broadcasting and multi hop communications will be dominant in VANETs safety applications and protocols. Therefore, a Network Topology p-Persistence (NTPP) scheme is proposed to alleviate the impact of the broadcast storm problem. NTPP is based on vehicles’ knowledge of their neighbors in their range and traffic parameters to reduce the channel contention, redundant re-broadcasts and message travel time and to increase the emergency message reception rate. We analyze the reliability of the IEEE 802.11p in VANETs safety and warning applications scope taking into consideration different factors. It is shown analytically and by extensive simulations that the current DSRC specifications may lead to undesirable performance under harsh vehicular environments. Therefore, a novel Distributed Multichannel and Mobility Aware Cluster-based MAC Protocol (DMCMAC) is proposed to alleviate the impact of the hidden terminal problem, increase the network capacity and reliability. Cluster heads in DMCMAC are elected and re-elected in a distributed manner according to their relative speed and distance from their cluster members. The high stability of DMCMAC results from its adaptability to drivers’ behavior on the road and its learning process to predict the future speed and position of all cluster members using the fuzzy logic inference system. The reliability of DMCMAC is analyzed and compared with other protocols. It is shown by simulations that DMCMAC has high stability, its performance exceeds other protocols and can achieve a timely and reliable delivery of emergency messages to their intended recipients which make it more suitable for VANETs. iv

scholarly journals A Semi-Stochastic Propagation Model for the Study of Beam Tilting in Cellular Systems

2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
Konstantinos B. Baltzis
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Signal To Noise Ratio ◽  
Base Station ◽  
Cellular Systems ◽  
Propagation Model ◽  
Beam Tilting ◽  
Tilting Angle ◽  
Proposed Model ◽  
The Impact

Base station antenna downtilt mitigates interference and improves the downlink performance of wireless systems. A semi-stochastic propagation model is presented and applied to the study of the impact of the base station beam tilting in cellular communications. The two-ray approximation of the proposed model is described analytically. Beam tilting is evaluated in relation to the base station antenna radiation pattern, the antennas height, the propagation environment, the bit error rate, and the signal-to-noise ratio at the receiver front end. Analytically derived expressions for the fading envelopes, the error probability, the optimum tilting angle, and the downlink capacity of a WCDMA system are derived. Theoretical analysis and simulation results are provided to show the characteristics of the model. Comparisons with data in the literature confirm its validity. Furthermore, the effect of beam tilting on system downlink performance in terms of bit error rate and capacity is investigated.

Usage Profiles

2013 ◽  
Vol 10 (1) ◽  
pp. 1-28 ◽  
Author(s):  
Bruno Vollino ◽  
Karin Becker
Keyword(s):  
Life Cycle ◽  
Web Services ◽  
Experimental Results ◽  
Consumption Patterns ◽  
Clear Understanding ◽  
Discovery Process ◽  
Service Usage ◽  
The Real ◽  
Compatibility Analysis ◽  
The Impact

As part of web services life-cycle, providers frequently face decision about changes without a clear understanding of the impact on their clients. The identification of clients’ consumption patterns constitutes invaluable information to support more effective decisions. In this paper, the authors present a framework that supports the discovery of service usage profiles, to bring awareness on the distinct groups of consumers, and their usage characterization in terms of detailed service functionality. The framework encompasses a process to cluster client applications and derive usage profiles. The paper also discusses how usage profiles can help to access the real impact on clients of incompatible changes performed over service descriptions, and presents a usage-oriented compatibility assessment algorithm. Experimental results are presented for both the profile discovery process and profile-based compatibility analysis.

scholarly journals The impact of semantics on aspect level opinion mining

2021 ◽  
Vol 7 ◽  
pp. e558
Author(s):  
Eman M. Aboelela ◽  
Walaa Gad ◽  
Rasha Ismail
Keyword(s):  
Sentiment Analysis ◽  
Semantic Similarity ◽  
Opinion Mining ◽  
Online Shopping ◽  
Experimental Results ◽  
Proposed Model ◽  
Online Comments ◽  
The Impact ◽  
F Measure ◽  
The Web

Recently, many users prefer online shopping to purchase items from the web. Shopping websites allow customers to submit comments and provide their feedback for the purchased products. Opinion mining and sentiment analysis are used to analyze products’ comments to help sellers and purchasers decide to buy products or not. However, the nature of online comments affects the performance of the opinion mining process because they may contain negation words or unrelated aspects to the product. To address these problems, a semantic-based aspect level opinion mining (SALOM) model is proposed. The SALOM extracts the product aspects based on the semantic similarity and classifies the comments. The proposed model considers the negation words and other types of product aspects such as aspects’ synonyms, hyponyms, and hypernyms to improve the accuracy of classification. Three different datasets are used to evaluate the proposed SALOM. The experimental results are promising in terms of Precision, Recall, and F-measure. The performance reaches 94.8% precision, 93% recall, and 92.6% f-measure.

scholarly journals Influence of Initial State Errors on Perturbation Guidance Accuracy

2019 ◽  
Vol 69 (1) ◽  
pp. 10-19
Author(s):  
Wuxing Jing ◽  
Xu Zheng ◽  
Changsheng Gao
Keyword(s):  
Long Range ◽  
Propagation Model ◽  
Impact Point ◽  
Initial State ◽  
The Real ◽  
Guidance And Control ◽  
Influence Mechanism ◽  
The Earth ◽  
And Control ◽  
The Impact

The inertial navigation system is aligned and leveled before the launch of a long-range vehicle. However, the initial state errors caused by the non-uniformity of the Earth can influence the parameters in flight dynamics, which will bring about serious uncertainty for the impact point of a long-range vehicle. Firstly, this paper analyses the influence mechanism of initial state errors on nominal trajectory, navigation trajectory and guidance trajectory. Then, a propagation model of engine-cutoff state deviation caused by initial state errors is derived under the condition of without-guidance. On this basis, an accuracy analytical solution of initial state errors on perturbation guidance is finally proposed to obtain the real impact-point of the long-range vehicle. In the simulations, the influence properties of initial state errors on perturbation guidance is analysed, give influence regularities of single initial state error, and obtain the statistical properties of engine-cutoff state deviations and impact-point deviation by Monte Carlo technique. From the simulation results, it seems that the navigation state tracks the nominal state. However, the real impact- point deviation has not been truly eliminated, instead of the almost target-hit deviation calculated by navigation output. The proposed analytical guidance accuracy model can be rapidly computed to provide a compensation for guidance and control system to improve hit accuracy.

scholarly journals A Multi-Attention Network for Aspect-Level Sentiment Analysis

2019 ◽  
Vol 11 (7) ◽  
pp. 157 ◽  
Author(s):  
Qiuyue Zhang ◽  
Ran Lu
Keyword(s):  
Neural Networks ◽  
Sentiment Analysis ◽  
Specific Aspect ◽  
Experimental Results ◽  
Sequence Information ◽  
Attention Network ◽  
Attention Networks ◽  
Recent Advances ◽  
Proposed Model ◽  
The Impact

Aspect-level sentiment analysis (ASA) aims at determining the sentiment polarity of specific aspect term with a given sentence. Recent advances in attention mechanisms suggest that attention models are useful in ASA tasks and can help identify focus words. Or combining attention mechanisms with neural networks are also common methods. However, according to the latest research, they often fail to extract text representations efficiently and to achieve interaction between aspect terms and contexts. In order to solve the complete task of ASA, this paper proposes a Multi-Attention Network (MAN) model which adopts several attention networks. This model not only preprocesses data by Bidirectional Encoder Representations from Transformers (BERT), but a number of measures have been taken. First, the MAN model utilizes the partial Transformer after transformation to obtain hidden sequence information. Second, because words in different location have different effects on aspect terms, we introduce location encoding to analyze the impact on distance from ASA tasks, then we obtain the influence of different words with aspect terms through the bidirectional attention network. From the experimental results of three datasets, we could find that the proposed model could achieve consistently superior results.

scholarly journals Design and Analysis of an Efficient and Reliable Mac Protocol for Vanets

2021 ◽  
Author(s):  
Khalid Abdel Hafeez
Keyword(s):  
High Stability ◽  
Mac Protocol ◽  
Network Capacity ◽  
Wireless Channel ◽  
Propagation Model ◽  
Ieee 802.11P ◽  
Inference System ◽  
Hidden Terminal ◽  
On The Road ◽  
The Impact

The increase number of vehicles on roads and the immense number of fatal accidents they cause have driven the research and development of new generation technologies to help drivers travel more safely. One major cause of traffic accidents is that drivers cannot consistently respond to the changing road conditions appropriately. In fact, most accidents could be avoided if drivers could obtain and use relevant information of the traffic that is beyond their vision using wireless communications technology. Recently, the IEEE community adopted the IEEE 802.11p standard as a main technology for VANETs. To test the feasibility of this technology, most researchers use simulations to evaluate its new applications and protocols due to the prohibitive cost of implementing real VANET setup. Therefore, we first analyze VANET’s wireless channel analytically and by simulations to predict its most appropriate propagation model and the communication range that minimizes the impact of the hidden terminal problem. Second, we derive a new mobility model that takes into account the vehicle’s follow-on safety rule, to accurately derive the relationship between vehicle’s speed and network density. It is expected that broadcasting and multi hop communications will be dominant in VANETs safety applications and protocols. Therefore, a Network Topology p-Persistence (NTPP) scheme is proposed to alleviate the impact of the broadcast storm problem. NTPP is based on vehicles’ knowledge of their neighbors in their range and traffic parameters to reduce the channel contention, redundant re-broadcasts and message travel time and to increase the emergency message reception rate. We analyze the reliability of the IEEE 802.11p in VANETs safety and warning applications scope taking into consideration different factors. It is shown analytically and by extensive simulations that the current DSRC specifications may lead to undesirable performance under harsh vehicular environments. Therefore, a novel Distributed Multichannel and Mobility Aware Cluster-based MAC Protocol (DMCMAC) is proposed to alleviate the impact of the hidden terminal problem, increase the network capacity and reliability. Cluster heads in DMCMAC are elected and re-elected in a distributed manner according to their relative speed and distance from their cluster members. The high stability of DMCMAC results from its adaptability to drivers’ behavior on the road and its learning process to predict the future speed and position of all cluster members using the fuzzy logic inference system. The reliability of DMCMAC is analyzed and compared with other protocols. It is shown by simulations that DMCMAC has high stability, its performance exceeds other protocols and can achieve a timely and reliable delivery of emergency messages to their intended recipients which make it more suitable for VANETs. iv

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