检索结果-南通市图书馆

Effect of change of sand properties on travel distance of ricocheted debris

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2021年第4期17卷 1486-1495页

作者： Yoon Keon kim woo Chun Choi Department of Mechanical Engineering Korea University145 Anam-roSeongbuk-guSeoul02841Republic of Korea

The debris from exploded buildings can ricochet after colliding with the ground,thus increasing the debris travel distance and danger from any associated impacts or *** reduce this danger,the travel distance of ricocheted debris must be accurately *** study analyzed the change in the travel distance of ricocheted concrete debris relative to changes in the properties of a sand *** shear tests were conducted to measure the change in internal friction angle as a function of temperature and water content of the *** element analysis(FEA)was then applied to these variables to predict the speed and angle of the debris after *** FEA results were compared with results of low-speed ricochet experiments,which employed variable temperature and water *** travel distance of the debris was calculated using MATLAB,via trajectory equations considering the drag *** the internal friction angle decreased,the shear stress decreased,leading to deeper penetration of the debris into the *** the loss of kinetic energy increased,the velocity and travel distance of the ricocheted debris *** in the ricochet velocity and travel distance of the debris,according to changes in the internal friction angle,indicated that the debris was affected by the environment.

关键词： Ricochet Exploded debirs Environmental change Sand Temperature Water content Internal friction angle Travel distance

Parasitic Robot System for Waypoint Navigation of Turtle

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2017年第2期14卷 327-335页

作者： Dae-gun kim Serin Lee Cheol-Hu kim Sungho Jo Phill-Seung Lee Department of Mechanical Engineering Korea Advanced Institute of Science and Technology (KAIST) 373-1 Guseong-dong Yuseong-gu Daejeon 34141 Republic of Korea Institute for Infocomm Research 1 Fusionopolis Way #21-01 Connexis Singapore Department of Computer Science Korea Advanced Institute of Science and Technology (KAIST) 373-1 Guseong-dong Yuseong-gu Daejeon 34141 Republic of Korea

In research on small mobile robots and biomimetic robots, locomotion ability remains a major issue despite many advances in technology. However, evolution has led to there being many real animals capable of exceUent locomotion. This paper presents a ＂parasitic robot system＂ whereby locomotion abilities of an animal are applied to a robot task. We chose a turtle as our first host animal and designed a parasitic robot that can perform ＂operant conditioning＂. The parasitic robot, which is attached to the turtle, can induce object-tracking behavior of the turtle toward a Light Emitting Diode （LED） and positively reinforce the behavior through repeated stimulus-response interaction. After training sessions over five weeks, the robot could successfully control the direction of movement of the trained turtles in the waypoint navigation task. This hybrid animal-robot interaction system could provide an alternative solution to some of the limitations of conventional mobile robot systems in various fields, and could also act as a useful interaction system for the behavioral sciences.

关键词： parasitic robot operant conditioning waypoint navigation red-eared slider trachemys scripta elegans

Characteristics of machined surface controlled by cutting tools and conditions in machining of brittle material

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2009年第B09期19卷 194-201页

作者： Yong-woo kim Soo-Chang CHOI Jeung-woo PARK Deug-woo LEE Department of Nano Fusion Technology Pusan National University Department of Mechanical Design Engineering Chosun University Department of Nanosystem and Nanoprocess Engineering Pusan National University

One of the ultra-precision machining methods was adapted for brittle material as well as soft material by using multi-arrayed diamond tips and high speed spindle. Conventional machining method is too hard to control surface roughness and surface texture against brittle material because the particles of grinding tools are irregular size and material can be fragile. Therefore, we were able to design tool paths and machine controlled pattern on surface by multi-arrayed diamond tips with uniform size made in MEMS fabrication and high speed spindle, and the maximum speed was about 3×105 r/min. We defined several parameters that can affect the machining surface. Those were multi-array of diamond tips (n×n), speed of air spindle and feeding rate. The surface roughness and surface texture can be controlled by those parameters for micro machining.

关键词：加工表面脆性材料条件控制刀具路径表面粗糙度特征高速主轴加工方法

Deep Drawing Process Using a Tractrix Die for Manufacturing Liners for a CNG High-Pressure Vessel(Type Ⅱ)

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2022年第1期35卷 132-143页

作者： gun‑Young Park Hyo‑Seo Kwak Hyo‑Seong Jang Chul kim School of Mechanical Engineering Pusan National UniversityPusan 46241South Korea Department of Mechanical Engineering Dong-eui UniversityPusan 47340Korea.

The liner of a CNG pressure vessel is manufactured by a DDI(deep drawing and ironing)process for the cylinder part,which is a continuous process that includes a drawing process to reduce the diameter of the billet and a subsequent ironing process to reduce the thickness of the billet.A tractrix die used in the 1^(st) deep drawing allows the blank to flow smoothly by decreasing the punch load and radial tensile stress occurring in the *** also increases the draw ratio compared to conventional dies,but it causes forming *** this study,a shape coefficient(S_(c))is proposed for the tractrix die using the blank diameter(D_(0)),inflow diameter of the workpiece(d_(i)),and inflow angle of the workpiece(θ)for design of the tractrix *** effects of the thickness and inflow angle of the workpiece on wrinkling and folding were investigated through ***,a discriminant is proposed for the relative radial stress(σ)generated during the deep drawing process using the tractirx die and used to predict *** on the results,the blank thickness,the draw ratio,and the inflow of the workpiece angle in the 1^(st) deep drawing process are suggested,and the number of operations in the DDI process was reduced from 6 to *** improves the productivity and reduces the manufacturing cost.

关键词： Tractrix die Deep drawing Wrinkling Folding LDR(Limit draw ratio) FEM

A DNA sequence alignment algorithm using quality information and a fuzzy inference method

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2008年第5期18卷 595-602页

作者： Kwangbaek kim Minhwan kim Youngwoon woo Division of Computer and Information Engineering Silla University School of Computer Science and Engineering Pusan National University Department of Multimedia Engineering Dong-Eui University Busan Republic of Korea

DNA sequence alignment algorithms in computational molecular biology have been improved by diverse methods. In this paper, we propose a DNA sequence alignment that uses quality information and a fuzzy inference method developed based on the characteristics of DNA fragments and a fuzzy logic system in order to improve conventional DNA sequence alignment methods that uses DNA sequence quality information. In conventional algorithms, DNA sequence alignment scores are calculated by the global sequence alignment algo- rithm proposed by Needleman–Wunsch, which is established by using quality information of each DNA fragment. However, there may be errors in the process of calculating DNA sequence alignment scores when the quality of DNA fragment tips is low, because only the overall DNA sequence quality information are used. In our proposed method, an exact DNA sequence alignment can be achieved in spite of the low quality of DNA fragment tips by improvement of conventional algorithms using quality information. Mapping score param- eters used to calculate DNA sequence alignment scores are dynamically adjusted by the fuzzy logic system utilizing lengths of DNA frag- ments and frequencies of low quality DNA bases in the fragments. From the experiments by applying real genome data of National Center for Biotechnology Information, we could see that the proposed method is more e cient than conventional algorithms.

关键词： DNA sequence alignment Quality information Fuzzy inference

k-Nearest Neighbor Query Processing Algorithms for a Query Region in Road Networks

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2013年第4期28卷 585-596页

作者： Hyeong-Il kim Jae-woo Chang Department of Computer Engineering Chonbuk National University Cloud Open R&D Center Chonbuk National University

Recent development of wireless communication technologies and the popularity of smart phones .are making location-based services （LBS） popular. However, requesting queries to LBS servers with users＇ exact locations may threat the privacy of users. Therefore, there have been many researches on generating a cloaked query region for user privacy protection. Consequently, an efficient query processing algorithm for a query region is required. So, in this paper, we propose k-nearest neighbor query （k-NN） processing algorithms for a query region in road networks. To efficiently retrieve k-NN points of interest （POIs）, we make use of the Island index. We also propose a method that generates an adaptive Island index to improve the query processing performance and storage usage. Finally, we show by our performance analysis that our k-NN query processing algorithms outperform the existing k-Range Nearest Neighbor （kRNN） algorithm in terms of network expansion cost and query processing time.

关键词： island index k-nearest neighbor query processing scheme locatiombased service road network

Analysis of Feature Importance and Interpretation for Malware Classification

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2020年第12期65卷 1891-1904页

作者： Dong-wook kim gun-Yoon Shin Myung-Mook Han Department of Computer Engineering Gachon UniversitySungnam-si13120Korea Department of Software Gachon UniversitySungnam-si13120Korea

This study was conducted to enable prompt classification of malware,which was becoming increasingly *** do this,we analyzed the important features of malware and the relative importance of selected features according to a learning model to assess how those important features were ***,the analysis features were extracted using Cuckoo Sandbox,an open-source malware analysis tool,then the features were divided into five categories using the extracted *** 804 extracted features were reduced by 70%after selecting only the most suitable ones for malware classification using a learning model-based feature selection method called the recursive feature ***,these important features were *** level of contribution from each one was assessed by the Random Forest classifier *** results showed that System call features were mostly *** the end,it was possible to accurately identify the malware type using only 36 to 76 features for each of the four types of malware with the most analysis samples *** were the Trojan,Adware,Downloader,and Backdoor malware.

关键词： Recursive feature elimination model interpretability feature importance malware classification

Unknown Attack Detection:Combining Relabeling and Hybrid Intrusion Detection

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2021年第9期68卷 3289-3303页

作者： gun-Yoon Shin Dong-wook kim Sang-Soo kim Myung-Mook Han Department of Computer Engineering Gachon UniversitySungnam-si13120Korea Agency for Defense Development Songpa Seoul05661Korea Department of Software Gachon UniversitySungnam-si13120Korea

Detection of unknown attacks like a zero-day attack is a research field that has long been ***,advances in Machine Learning(ML)and Artificial Intelligence(AI)have led to the emergence of many kinds of attack-generation tools developed using these technologies to evade detection *** detection and misuse detection are the most commonly used techniques for detecting intrusion by unknown *** anomaly detection is adequate for detecting unknown attacks,its disadvantage is the possibility of high false *** detection has low false alarms;its limitation is that it can detect only known *** overcome such limitations,many researchers have proposed a hybrid intrusion detection that integrates these two detection *** method can overcome the limitations of conventional methods and works better in detecting unknown ***,this method does not accurately classify attacks like similar to normal or known ***,we proposed a hybrid intrusion detection to detect unknown attacks similar to normal and known *** anomaly detection,the model was designed to perform normal detection using Fuzzy c-means(FCM)and identify attacks hidden in normal predicted data using *** misuse detection,the model was designed to detect previously known attacks using Classification and Regression Trees(CART)and apply Isolation Forest(iForest)to classify unknown attacks hidden in known *** an experiment result,the application of relabeling improved attack detection accuracy in anomaly detection by approximately 11%and enhanced the performance of unknown attack detection in misuse detection by approximately 10%.

关键词： Unknown attack hybrid intrusion detection fuzzy c-means relabeling CART iForest

Effects of ozonation and coagulation on effluent organic matter characteristics and ultrafiltration membrane fouling

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2014年第6期26卷 1325-1331页

作者： Kwon Jeong Dae-Sung Lee Do-gun kim Seok-Oh Ko Department of Civil Engineering Kyung Hee UniversityYongin 446-701 Korea Institute of Construction Technology KUMHO Engineering & ConstructionYongin 449-822 Korea

Effluent organic matter （EfOM） is the major cause of fouling in the low pressure membranes process for wastewater reuse. Coagulation and oxidation of biological wastewater treatment effluent have been applied for the fouling control of microfiltration membranes. However, the change in EfOM structure by pre-treatments has not been clearly identified. The changes of EfOM characteristics induced by coagulation and ozonation were investigated through size exclusion chromatography, UV/Vis spectrophotometry, fluorescence spectrophotometry and titrimetric analysis to identify the mechanisms in the reduction of ultrafiltration （UF） membrane fouling. The results indicated that reduction of flux decline by coagulation was due to modified characteristics of dissolved organic carbon （DOC） content. Total concentration of DOC was not reduced by ozonation. However, the mass fraction of the molecules with molecular weight larger than 5 kDa, fluorescence intensity, aromaticity, highly condensed chromophores, average molecular weight and soluble microbial byproducts decreased greatly after ozonation. These results indicated that EfOM was partially oxidized by ozonation to low molecular weight, highly charged compounds with abundant electron- withdrawing functional groups, which are favourable for alleviating UF membrane flux decline.

关键词： effluent organic matter fouling ultrafiltration oxidation molecular weight distribution acidity