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Kinematic Analysis of an Under-actuated,Closed-loop Front-end Assembly of a Dragline Manipulator

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International Journal of Automation and computing 2020年第4期17卷 527-538页

作者： Muhammad AWardeh samuel frimpong Department of Mining and Nuclear Engineering Missouri University of Science and TechnologyRolla 65409USA Center for Infrastructure Engineering Studies Missouri University of Science and TechnologyRolla 65409USADepartment of Mining and Nuclear EngineeringMissouri University of Science and TechnologyRolla 65409USA

Dragline excavators are closed-loop mining manipulators that operate using a rigid multilink framework and rope and rigging system,which constitute its front-end *** arrangements of dragline front-end assembly provide the necessary motion of the dragline bucket within its operating *** assembly resembles a five-link closed kinematic chain that has two independent generalized coordinates of drag and hoist ropes and one dependent generalized coordinate of dump *** models failed to represent the actual closed loop of dragline front-end assembly,nor did they describe the maneuverability of dragline ropes under imposed geometric ***,a three degrees of freedom kinematic model of the dragline front-end is developed using the concept of generalized *** contains all relevant configuration and kinematic constraint conditions to perform complete digging and swinging *** model also uses three inputs of hoist and drag ropes linear and a rotational displacement of swinging along their *** inverse kinematics is resolved using a feedforward displacement algorithm coupled with the Newton-Raphson method to accurately estimate the trajectories of the *** trajectories are solved only during the digging phase and the singularity was eliminated using Baumgarte's stabilization technique(BST),with appropriate inequality constraint *** is shown that the feedforward displacement algorithm can produce accurate trajectories without the need to manually solve the inverse kinematics from the *** research findings are well in agreement with the dragline real operational limits and they contribute to the efficiency and the reduction in machine downtime due to better control strategies of the dragline cycles.

关键词： Dragline mining manipulator underactuated closed-loop mechanism generalized speeds Baumgarte's stabilization technique(BST) feedforward displacement

A Quadratic Programming Model for Blast Scheduling

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International Journal of Minerals,Metallurgy and Materials 1999年第3期13卷 165-167页

作者： Chunyan Meng samuel frimpong Mingjian Zuo(Ph. D. Student (correspondent). 606-Chemical-Mineral Building. Dept of Civil and Environmental Engineering. University of Alberta. T6G 2G6.Edmonton, AB. Canada)(Associate protessor, School of Mining and Petrole 606-Chemical-Mineral Building Dept of Civil and Environmental Engineering University of Alberta Edmonton Alta. T6G 2G6 Canada School of Mining and Petroleum Engineering University of Alberta Canada Department of Mechanical Engineering University of Alberta Canada

A quadratic programming model is established to choose the blocks to be blasted in a given period. The length of this period depends on the production planning requirements. During the given period, the blocks' parameters are available from the geological database of the mine. The objective is to minimize the deviation of the average ore grade of blasted blocks from the standard ore grade required by the mill. Transportation ability constraint. production quantity demand constraint. minimum safety bench constraint. block size constraint and block, bench precedence constraints are considered in forming the programming model. This model has more practical objective function and reasonable constraints compared with the existing model for this kind of problems.

关键词： quadratic programming open pit mining blast scheduling mine production scheduling mathematical programming model

RecGuard: An efficient privacy preservation blockchain-based system for online social network users

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Blockchain(Research and Applications) 2023年第1期4卷 36-47页

作者： samuel Akwasi frimpong Mu Han Edward Kwadwo Boahen Rexford Nii Ayitey Sosu Isaac Hanson Otu Larbi-Siaw Isaac Baffour Senkyire Department of Computer Science and Technology Jiangsu University212013ZhenjiangChina Department of Computer Engineering Ghana Communication Technology UniversityGhana Department of Computer Science Ghana Communication Technology UniversityGhana Department of Telecom Engineering Ghana Communication Technology UniversityGhana School of Finance and Economics Jiangsu University 212013ZhenjiangChina

Recommendation systems provide ease and convenience for users to address information overload problems while interacting with online platforms such as social media and ***,it raises several questions about privacy,especially for users who prefer to remain anonymous,especially on online social networks(OSNs).Moreover,due to the commercialization of online users'data,some service providers sell users'data to third parties at the blind side of the users,which leads to trust issues between users and service *** matters call for a system that gives online users much-needed control and autonomy of their *** the advancement of blockchain technology,many research institutions are experimenting with decentralized technologies to resolve the OSN user dilemma of privacy intrusion against third parties and *** resolve these limitations,we propose RecGuard,a privacy preservation blockchain-based network *** developed two smart contracts,RG-SH and RG-ST,to ensure the security and privacy of user *** RG-SH manages user data,whereas the RGST stores data.A graph convolutional network(GCN)was integrated with the blockchain-based system to detect malicious ***,we implemented our framework prototype on a locally simulated *** analysis and experiment results show that the proposed scheme demonstrates the effectiveness and privacy of users in our framework.

关键词： Blockchain Privacy Online social network Recommender system

Virtual Prototype Modeling and Simulation of Pipe Wagon Articulating System

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Modern Mechanical Engineering 2011年第2期1卷 38-46页

作者： Ying Li samuel frimpong Wenyuan Liu 不详

Virtual prototype of pipe wagon articulating (PWA) system has been developed and simulated based on the kinematics and dynamics of machinery and Automatic Dynamic Analysis of Mechanical Systems (ADAMS) software. It has been integrated with real-time three dimensional (3-D) system simulations for detailed and responsive interaction with dynamic virtual environments. By using this virtual model, the conceptual design examination and performance analysis of the PWA system have been realized dynamically in virtual laboratory. System dynamic force, displacement and tension of pipe have been measured through verifying this 3- D virtual prototype. By comparing the static tension and dynamic tension of pipe, the difference between the two kind tensions has been found. The simulated dynamic tension is much greater than the static tension obtained from the static theory. The results attained in this work suggest that the conceptual designed PWA system can meet the requirements of the operation.

关键词： Pipe Wagon Articulating Dynamic Modeling Virtual Prototype Dynamic Simulation

金融风险对商业银行绩效的影响——基于加纳的分析

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金融风险对商业银行绩效的影响——基于加纳的分析

作者： samuel frimpong 江苏大学

学位级别：硕士

本研究的主要目的是确定金融风险对加纳商业银行财务业绩的影响。尽管银行业具有稳定性和恢复力,但在2018年,加纳银行对当地无力偿债的五家银行因予以吊销营业执照,并将其资产合并为一家新的国有独资实体,即加纳综合银行有限公司(CBG)... 详细信息

本研究的主要目的是确定金融风险对加纳商业银行财务业绩的影响。尽管银行业具有稳定性和恢复力,但在2018年,加纳银行对当地无力偿债的五家银行因予以吊销营业执照,并将其资产合并为一家新的国有独资实体,即加纳综合银行有限公司(CBG)。论文采用R Statistical Package Software进行数据分析和解释,对选定的加纳十五家银行利用次级资料研究其信用风险、流动性风险、利率风险、资本管理风险、市场风险等对银行规模和银行存款的影响。采用普通最小二乘估计法以及固定和随机效应模型进行初步分析。为了检验研究的稳健性,采用扩张性Dickey-Fuller单元根进行检验,结果表明,一阶差分后的数据序列达到平稳。数据分析显示,以资产回报率(ROA)为代表的银行财务绩效与银行部门财务风险变量之间存在显著的长期关系;格兰杰因果检验结果表明,金融风险变量存在单向因果关系。这表明金融风险指标有刺激和改善加纳银行的财务业绩的作用。论文还采用时间序列向量误差修正模型(VECM)方法进行了协整检验,结果表明无论是短期还是长期,财务绩效都取决于财务风险变量。据此论文提出了以下对策建议:银行管理人员应改进财务风险变量所有指标的管理以改进公司目标的实现;银行管理者应制定一个高效、有效的风险管理框架,以管理资产负债表中的风险,并实现最高附加值;商业银行应该专注于对冲和预测决定利率的宏观经济因素,而不是专注于利率;管理者应确保商业银行将多余的现金投资于生产性资产,这确保了他们不会以牺牲能够提高盈利能力的固定资产为代价持有多余的现金;管理人员应引导其银行进行外汇交易,并控制好外汇风险,因为外汇风险的增加会导致商业银行的业绩或盈利能力下降。

关键词：加纳银行金融风险财务业绩影响扩张性Dickey-Fuller单位根验格兰杰因果检验

Exposure to sublethal concentration of flupyradifurone alters sexual behavior and cuticular hydrocarbon profile in Heriades truncorum,an oligolectic solitary bee

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Insect Science 2024年第3期31卷 859-869页

作者： samuel Boff Manfred Ayasse Institute of Evolutionary Ecology and Conservation Genomics Ulm UniversityUlmGermany

The aboveground oligolectic bee,Heriades truncorum,is a particularly good model for studying the impact of pesticides on sexual communication,since some aspects of its mating behavior have previously been *** have tested(1)the interference of the pesticide flupyradifurone on male precopulatory behavior and male mating partner preferences,(2)the way that the pesticide interferes in male quality assessment by the female,and(3)the effects of the pesticide on the chemical compounds in the female *** exposed bees of both sexes to a sublethal concentration of *** behaviors were registered in a mating arena with two females(one unexposed and one exposed)and one male(either unexposed or exposed).Unexposed males were quicker to attempt to *** also impacted precopulatory behavior and male quality assessment by *** approached unexposed females more quickly than insecticideexposed *** exposed to insecticide produced lower amounts of some cuticular hydrocarbons(sex pheromone candidates)and appeared less choosy than unexposed *** findings suggest that insecticide exposure affects sexual communication,playing a role both in male preference and in male quality assessment by the female.

关键词： courtship display female choice flupyradifurone male partner preference sex communication sublethal effects

The influence of various grease compositions and silver nanoparticle additives on electrically induced rolling-element bearing damage

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Friction 2024年第4期12卷 796-811页

作者： samuel BOND Robert L.JACKSON German MILLS Department of Chemistry and Biochemistry Auburn UniversityAuburn 36849-5412USA Department of Mechanical Engineering Auburn UniversityAuburn 36849-5412USA

Leakage currents accelerate surface degradation of metal contacts via small scale arcing across lubricating films,but recent observations suggest that metallic nanoparticle additives in lubricants may be useful to improve contact *** findings prompted a study that examined electrically induced surface pitting of steel contacts in the presence of several lubricating greases including some containing nanometer-sized colloidal silver(Ag)*** rolling sphere-on-disk experiments were conducted under electro-tribological loads employing polyurea greases derived from mineral and synthetic base oils with and without *** forces and electrical resistance were monitored continuously during the tests;surface changes were characterized by means of optical spectroscopy,stylus profilometry,and scanning electron microscopy(SEM)including compositional analysis using energy dispersive spectroscopy(EDS).The observations demonstrate that surface pitting induced by arcing occurs mainly at the points were the rolling motion changes direction and that eroded metal is deposited along the wear ***-sized pits are formed which contain carbon and oxygen indicating that arcing causes decomposition of the hydrocarbon *** findings indicate a significant inhibition of pitting is induced by the Ag nanoparticles;some greases containing other additives exhibit a similar,although less pronounced,effect.

关键词： electric motor bearings wheel bearings electric vehicles arcing electrically induced bearing damage pitting leakage current stray current

Ethical decision-making in older drivers during critical driving situations: An online experiment

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Journal of Intelligent and Connected Vehicles

Journal of Intelligent and Connected Vehicles 2024年第1期7卷 30-37页

作者： Amandeep Singh Sarah Yahoodik Yovela Murzello samuel Petkac Yusuke Yamani Siby samuel Department of Systems Design Engineering University of WaterlooWaterloo N2L 3G1Canada Department of Psychology Old Dominion UniversityNorfolk 23529USA

The present study examined the impact of aging on ethical decision-making in simulated critical driving scenarios.204 participants from North America,grouped into two age groups(18–30 years and 65 years and above),were asked to decide whether their simulated automated vehicle should stay in or change from the current lane in scenarios mimicking the Trolley *** participant viewed a video clip rendered by the driving simulator at Old Dominion University and pressed the space-bar if they decided to intervene in the control of the simulated automated vehicle in an online *** hierarchical models were used to analyze participants’responses,response time,and acceptability of utilitarian ethical *** results showed significant pedestrian placement,age,and time-to-collision(TTC)effects on participants’ethical *** pedestrians were in the right lane,participants were more likely to switch lanes,indicating a utilitarian approach prioritizing pedestrian *** participants were more likely to switch lanes in general compared to older *** results imply that older drivers can maintain their ability to respond to ethically fraught scenarios with their tendency to switch lanes more frequently than younger counterparts,even when the tasks interacting with an automated driving *** current findings may inform the development of decision algorithms for intelligent and connected vehicles by considering potential ethical dilemmas faced by human drivers across different age groups.

关键词： ethical decision making age-differences utilitarianism moral dilemmas driver behavior simulated driving bayesian hierarchical model

Fish-on-Chips:unveiling neural processing of chemicals in small animals through precise fluidic control

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Neural Regeneration Research 2024年第11期19卷 2351-2353页

作者： samuel K.H.Sy Ho Ko Division of Neurology Department of Medicine and TherapeuticsFaculty of MedicineThe Chinese University of Hong KongShatinNew TerritoriesHong Kong Special Administrative RegionChina Li Ka Shing Institute of Health Sciences Faculty of MedicineThe Chinese University of Hong KongShatinNew TerritoriesHong Kong Special Administrative RegionChina Department of Electrical and Electronic Engineering Faculty of EngineeringThe University of Hong KongPok Fu LamHong Kong IslandHong Kong Special Administrative RegionChina Advanced Biomedical Instrumentation Center Hong Kong Science ParkPak Shek KokNew TerritoriesHong Kong Special Administrative RegionChina Margaret K.L.Cheung Research Center for Management of Parkinsonism Faculty of MedicineThe Chinese University of Hong KongShatinNew TerritoriesHong Kong Special Administrative RegionChina Lau Tat-chuen Research Center of Brain Degenerative Diseases in Chinese Faculty of MedicineThe Chinese University of Hong KongShatinNew TerritoriesHong Kong Special Administrative RegionChina Gerald Choa Neuroscience Institute The Chinese University of Hong KongShatinNew TerritoriesHong Kong Special Administrative RegionChina

Precise chemical cue presentation alongside advanced brainwide imaging techniques is important to the study of chemosensory processing in ***,the dynamic nature of chemical-carrying media,such as water or air,poses a significant challenge for delivering highly-controlled chemical flow to an animal ***,contact-based cue manipulation and delivery easily shift the position of the animal subject,which is often undesirable for high-quality brain ***,more advanced interfacing tools that align with the diverse range of body part sizes of an animal,ranging from micrometer-scale neurons to meter-long limbs,are much *** is particularly crucial when dealing with dimensions that are beyond the reach of conventional experimental tools.

关键词： dealing precise sizes