European Journal of Engineering and Formal Sciences最新文献_第2页

Experimental and Numerical Investigation for Mechanical Ventilated Greenhouse (Comparison between Different Turbulence Models) 机械通风温室的实验与数值研究(不同湍流模型的比较)

European Journal of Engineering and Formal Sciences Pub Date : 2018-12-29 DOI: 10.26417/ejef.v2i3.p107-115

A. Newir, M. A. Ibrahim

引用次数: 0

Virtual Learning Environments Practices, in the students of System Engineering of the Tecnologico Nacional de Mexico, Campus Mexicali 虚拟学习环境实践，墨西哥国立理工大学系统工程专业学生，墨西卡利校区

European Journal of Engineering and Formal Sciences Pub Date : 2018-12-29 DOI: 10.26417/ejef.v2i3.p63-65

Jesús Francisco Gutiérrez Ocampo, Corina Araceli Ortiz Perez, M. Camaño

引用次数: 0

Eigenfrequency and Euler's Critical Load Evaluation of Transversely Cracked Beams with a Linear Variation of Widths 宽度线性变化的横向裂纹梁的特征频率和欧拉临界荷载评价

European Journal of Engineering and Formal Sciences Pub Date : 2018-12-29 DOI: 10.26417/ejef.v2i3.p116-125

M. Skrinar

{"title":"Eigenfrequency and Euler's Critical Load Evaluation of Transversely Cracked Beams with a Linear Variation of Widths","authors":"M. Skrinar","doi":"10.26417/ejef.v2i3.p116-125","DOIUrl":"https://doi.org/10.26417/ejef.v2i3.p116-125","url":null,"abstract":"For a truthful evaluation of the mechanical response of structures reliable and adequate computational models are essential. Consequently, various researches have been devoted to the mathematical representation of cracked structures. This paper studies the performance of the simplified crack model in estimations of fundamental eigenfrequency as well as elastic Euler's critical load for transversely cracked beams of rectangular cross-sections with linearly-varying widths. To obtain these solutions for different beams with diverse boundary conditions Rayleigh’s energy method which requires an assumed transverse displacement function can be applied. After the appropriate displacement function is being selected, kinetic and strain energy, as well as the work done by an external axial compressive force P are evaluated. From these values, the estimations of the fundamental eigenfrequency, as well as the critical load, are assessed. To obtain these preliminary estimates, static deflection functions were applied initially. These functions represent a wide group of suitable functions since they automatically satisfy the required kinematic boundary conditions. Afterwards, alternative functions constructed from a dedicated polynomial solution were applied. Since this mathematical form offers straightforward integration, the genuinely applied displacement functions were further upgraded, separately for eigenfrequency as well as for critical load estimation. All obtained simplified model’s solutions were afterwards compared to the results from equivalent and more detailed 3D finite models of the examined structures. The comparisons of the results demonstrated very fine agreements with the results from 3D FE models for all performed analyses. The considered simplified model thus clearly yields a suitable alternative in modelling of cracked beams with a linear variation of width in those situations, where cracks have to be considered within the analysis.","PeriodicalId":143703,"journal":{"name":"European Journal of Engineering and Formal Sciences","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127120092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analysis of Dimensional Variations of Precision Gear Forging Die Geometry Due to Shrink Fit 精密齿轮锻模收缩配合尺寸变化分析

European Journal of Engineering and Formal Sciences Pub Date : 2018-12-29 DOI: 10.26417/ejef.v2i3.p87-95

O. Eyercioglu

{"title":"Analysis of Dimensional Variations of Precision Gear Forging Die Geometry Due to Shrink Fit","authors":"O. Eyercioglu","doi":"10.26417/ejef.v2i3.p87-95","DOIUrl":"https://doi.org/10.26417/ejef.v2i3.p87-95","url":null,"abstract":"The usual way to shrink fit design for precision forging dies are made by thick wall cylinder approach; i.e., taking the pitch diameter of the gear as bore diameter of the die insert without considering gear tooth shape. However, the compressive pre-stress due to the shrink fitting causes dimensional variations on the gear profile of the die insert. The dimensional accuracy of the final product is dependent on the accuracy of the gear die. Therefore, the dimensional variations due to shrink fit must be pre-determined and the gear tooth profile on the die insert modified accordingly. In this study, the dimensional variations of the precision spur gear forging die because of shrink fitting are analyzed by finite element method and the results are compared with the experimental ones. The results show that the FE model is successful to simulate the cylindrical die and agree well with thick wall cylinder approach and the experimental measurements. However, both the experimental measurements and the finite element results of gear die predict much higher radial displacements than the results of cylindrical die. Therefore, the determination of shape change of the gear die profile is beyond the capability of the thick wall cylindrical approach.","PeriodicalId":143703,"journal":{"name":"European Journal of Engineering and Formal Sciences","volume":"2000 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121075714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Study on Urban Sustainable Restructuring of Leinefelde, Germany and Revealing the Important Strategies for Environmental Well-Being for Shrinking Cities 德国Leinefelde城市可持续结构调整及其对萎缩城市环境福祉的启示

European Journal of Engineering and Formal Sciences Pub Date : 2018-12-29 DOI: 10.26417/ejef.v2i3.p76-85

Sri Charan

引用次数: 1

Anomaly-Based Intrusion Detection: Feature Selection and Normalization Influence to the Machine Learning Models Accuracy 基于异常的入侵检测:特征选择和归一化对机器学习模型精度的影响

European Journal of Engineering and Formal Sciences Pub Date : 2018-12-29 DOI: 10.26417/ejef.v2i3.p101-106

D. Protić, M. Stankovic

{"title":"Anomaly-Based Intrusion Detection: Feature Selection and Normalization Influence to the Machine Learning Models Accuracy","authors":"D. Protić, M. Stankovic","doi":"10.26417/ejef.v2i3.p101-106","DOIUrl":"https://doi.org/10.26417/ejef.v2i3.p101-106","url":null,"abstract":"Anomaly-based intrusion detection system detects intrusion to the computer network based on a reference model that has to be able to identify its normal behavior and flag what is not normal. In this process network traffic is classified into two groups by adding different labels to normal and malicious behavior. Main disadvantage of anomaly-based intrusion detection system is necessity to learn the difference between normal and not normal. Another disadvantage is the complexity of datasets which simulate realistic network traffic. Feature selection and normalization can be used to reduce data complexity and decrease processing runtime by selecting a better feature space This paper presents the results of testing the influence of feature selection and instances normalization to the classification performances of k-nearest neighbor, weighted k-nearest neighbor, support vector machines and decision tree models on 10 days records of the Kyoto 2006+ dataset. The data was pre-processed to remove all categorical features from the dataset. The resulting subset contained 17 features. Features containing instances which could not be normalized into the range [-1, 1] have also been removed. The resulting subset consisted of nine features. The feature ‘Label’ categorized network traffic to two classes: normal (1) and malicious (0). The performance metric to evaluate models was accuracy. Proposed method resulted in very high accuracy values with Decision Tree giving highest values for not-normalized and with k-nearest neighbor giving highest values for normalized data.Keywords: feature selection, normalization, k-NN, weighted k-NN, SVM, decision tree, Kyoto 2006+","PeriodicalId":143703,"journal":{"name":"European Journal of Engineering and Formal Sciences","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115617523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

Performance Analysis of Coded Frequency Division Multiplexing 编码频分复用的性能分析

European Journal of Engineering and Formal Sciences Pub Date : 2018-12-01 DOI: 10.2478/ejef-2018-0017

M. Farhan

引用次数: 0

Technology, Users, and Sustainable Social Housing 技术、用户和可持续社会住房

European Journal of Engineering and Formal Sciences Pub Date : 2018-12-01 DOI: 10.2478/ejef-2018-0014

Jan Johansson

引用次数: 0

Different Methods of Gas Turbine Engine Efficiency 燃气涡轮发动机效率的不同方法

European Journal of Engineering and Formal Sciences Pub Date : 2018-12-01 DOI: 10.2478/ejef-2018-0018

Samir Osman

引用次数: 0

Composite Materials Behavior Analyze for Desk, Hull and Board Yacht's Panel 桌型、船体及板式游艇面板复合材料性能分析

European Journal of Engineering and Formal Sciences Pub Date : 2018-12-01 DOI: 10.2478/ejef-2018-0016

Mirela Koci

引用次数: 0