On Realization of Program Constraints: Part II—Practical Implications

1989 ◽  
Vol 56 (3) ◽  
pp. 680-684 ◽  
Author(s):  
Wojciech Blajer ◽  
Jan Parczewski
Keyword(s):  
Mathematical Model ◽  
Different Types ◽  
General Mathematical Model ◽  
Practical Implications ◽  
Program Constraint

Practical implications of a general mathematical model of realization of program constraints are investigated. Illustrative examples of different types of this realization are demonstrated and discussed. Some general conclusions concerning the problem of program constraint realization are drawn.

A General Mathematical Model for Gears Cut by CNC Hobbing Machines

1997 ◽  
Vol 119 (1) ◽  
pp. 108-113 ◽  
Author(s):  
Shinn-Liang Chang ◽  
Chung-Biau Tsay ◽  
Shigeyoshi Nagata
Keyword(s):  
Mathematical Model ◽  
Degree Of Freedom ◽  
Cutting Process ◽  
Generation Process ◽  
Cutting Mechanism ◽  
Gear Cutting ◽  
Different Types ◽  
General Mathematical Model ◽  
Crossed Axes ◽  
The Mathematical Model

A hobbing machine’s cutting mechanism is a mechanism with multi-degree of freedom during the cutting process. In this paper, we propose a general gear mathematical model simulating the generation process of a 6-axis CNC hobbing machine based on the cutting mechanism of CNC hobbing machine and worm-type hob cutter. The proposed gear mathematical model can be applied to simulate different types of gear cutting. Some examples are included to verify the mathematical model. Also, a novel type of gear named “Helipoid” which can be used in crossed axes transmission is proposed. The proposed general gear mathematical model can facilitate a more thorough understanding of generation processes and toward the development of novel types of gears.

scholarly journals Advantages and potential challenges of data management in e-maintenance

2019 ◽  
Vol 25 (3) ◽  
pp. 378-396 ◽  
Author(s):  
Arian Razmi-Farooji ◽  
Hanna Kropsu-Vehkaperä ◽  
Janne Härkönen ◽  
Harri Haapasalo
Keyword(s):  
Data Management ◽  
Design Methodology ◽  
Management Practices ◽  
Future Research ◽  
Conceptual Approach ◽  
Content Type ◽  
Different Types ◽  
Maintenance Systems ◽  
Industry Leader ◽  
Practical Implications

Purpose The purpose of this paper is twofold: first, to understand data management challenges in e-maintenance systems from a holistically viewpoint through summarizing the earlier scattered research in the field, and second, to present a conceptual approach for addressing these challenges in practice. Design/methodology/approach The study is realized as a combination of a literature review and by the means of analyzing the practices on an industry leader in manufacturing and maintenance services. Findings This research provides a general understanding over data management challenges in e-maintenance and summarizes their associated proposed solutions. In addition, this paper lists and exemplifies different types and sources of data which can be collected in e-maintenance, across different organizational levels. Analyzing the data management practices of an e-maintenance industry leader provides a conceptual approach to address identified challenges in practice. Research limitations/implications Since this paper is based on studying the practices of a single company, it might be limited to generalize the results. Future research topics can focus on each of mentioned data management challenges and also validate the applicability of presented model in other companies and industries. Practical implications Understanding the e-maintenance-related challenges helps maintenance managers and other involved stakeholders in e-maintenance systems to better solve the challenges. Originality/value The so-far literature on e-maintenance has been studied with narrow focus to data and data management in e-maintenance appears as one of the less studied topics in the literature. This research paper contributes to e-maintenance by highlighting the deficiencies of the discussion surrounding the perspectives of data management in e-maintenance by studying all common data management challenges and listing different types of data which need to be acquired in e-maintenance systems.

The Generation Principle and Mathematical Models of Double-Enveloping Internal Gear Pairs

2015 ◽  
Author(s):  
Xuan Li ◽  
Bingkui Chen ◽  
Yawen Wang ◽  
Guohua Sun ◽  
Teik C. Lim
Keyword(s):  
Mathematical Model ◽  
Load Capacity ◽  
Geometrical Shape ◽  
Gear Pair ◽  
Numerical Examples ◽  
Proposed Model ◽  
General Mathematical Model ◽  
Meshing Characteristics ◽  
Internal Gear ◽  
Tooth Pair

In this paper, the planar double-enveloping method is presented for the generation of tooth profiles of the internal gear pair for various applications, such as gerotors and gear reducers. The main characteristic of this method is the existence of double contact between one tooth pair such that the sealing property, the load capacity and the transmission precision can be significantly improved as compared to the conventional configuration by the single-enveloping theory. Firstly, the generation principle of the planar double-enveloping method is introduced. Based on the coordinate transformation and the envelope theory, the general mathematical model of the double-enveloping internal gear pair is presented. By using this model, users can directly design different geometrical shape profiles to obtain a double-enveloping internal gear pair with better meshing characteristics. Secondly, to validate the effectiveness of the proposed model, specific mathematical formulations of three double-enveloping internal gear pairs which apply circular, parabolic and elliptical curves as the generating curves are given. The equations of tooth profiles and meshing are derived and the composition of tooth profiles is analyzed. Finally, numerical examples are provided for an illustration.

scholarly journals The profiling of university of Ljubljana students according to their motives for exercise participation

2017 ◽  
Vol 56 (2) ◽  
pp. 107-114 ◽  
Author(s):  
Katja Cerar ◽  
Miran Kondrič ◽  
Joško Sindik
Keyword(s):  
Physical Activity ◽  
Additional Data ◽  
Personal Data ◽  
Male Students ◽  
Main Research ◽  
Exercise Participation ◽  
Different Types ◽  
Participation Motives ◽  
The University ◽  
Practical Implications

Abstract Introduction The main research objective is the analysis of the grouping of the students of the University of Ljubljana, with respect to the intensity of different types of exercise participation motives, their gender, discipline and year of study, level of physical activity, status of physical education class, organization of physical activities during study, and place of residence. Methods Data were collected using personal data sheets during enrolling students at the University of Ljubljana. Students completed The Exercise Motivations Inventory (EMI-2), with additional data about sociodemographic parameters. Results The results reveal that the students could be grouped in three distinctive clusters, which can be very clearly explained in terms of the prevalence of exercise participation motives in general. The students grouped in the first cluster have the lowest average values (means) in all exercise participation motives. The students grouped in the second cluster have the profile with moderate means in all exercise participation motives, while the students grouped in the third cluster have the profile with the highest means in all exercise participation motives. Conclusions The results indicate overall higher motivation for physical activity in men. All the sub-samples are different in their relevant features used in clustering (e.g., male students are dominant in life sciences, etc.), which provide a guide both for the explanation of the results obtained and for practical implications.

When I am old I shall wear purple: a qualitative study of the effect of group poetry sessions on the well-being of older adults

2016 ◽  
Vol 20 (4) ◽  
pp. 195-198 ◽  
Author(s):  
Richard Seymour ◽  
Michael Murray
Keyword(s):  
Older People ◽  
Assisted Living ◽  
Well Being ◽  
Content Type ◽  
Short Period ◽  
Different Types ◽  
Poetry Reading ◽  
The Impact ◽  
Health And Well Being ◽  
Practical Implications

Purpose There is increasing evidence that participation in various art forms can be beneficial for health and well-being. The purpose of this paper is to examine the impact of participating in a poetry reading group on a group of older residents of an assisted living facility. Design/methodology/approach Six poetry sessions, each on a different theme, were conducted with a group of volunteer participants. These sessions, those of pre- and post-study focus groups and interviews with the group facilitator and staff contact were audio-recorded. The transcripts of the recordings were then subjected to a thematic analysis. Findings Overall the participants were enthused by the opportunity to participate in the project and the benefits were confirmed by the support staff. In addition, reading poetry on particular themes promoted different types of discussion. Research limitations/implications The number of participants in this study was small and the study was conducted over a short period of time. Practical implications This paper confirms the impact of poetry reading for older people. The challenge is to explore this impact in more detail and over community as well as residential settings. Originality/value This paper is the first empirical report on the value of poetry reading for older people.

Performance assessment of the complex repairable system with n-identical units under (k-out-of-n: G) scheme and copula linguistic repair approach

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
V. V. Singh ◽  
Abubakkar Idris Mohhammad ◽  
Kabiru Hamisu Ibrahim ◽  
Ibrahim Yusuf
Keyword(s):  
Complex System ◽  
Design Methodology ◽  
New Method ◽  
Social Implications ◽  
Repairable System ◽  
Variable Technique ◽  
Content Type ◽  
Different Types ◽  
Theoretical Assessment ◽  
Practical Implications

PurposeThis paper analyzed a complex system consisting n-identical units under a k-out-of-n: G; configuration via a new method which has not been studied by previous researchers. The computed results are more supportable for repairable system performability analysis.Design/methodology/approachIn this paper, the authors have analyzed a complex system consisting n-identical units under a k-out-of-n: G; configuration via a new method which has not been studied by previous researchers. The supplementary variable technique has employed for analyzing the performance of the system.FindingsReliability measures have been computed for different types of configuration. It generalized the results for purely series and purely parallel configurations.Research limitations/implicationsThis research may be beneficial for industrial system performances whereas a k-out-of-n-type configuration exists.Practical implicationsNot sure as it is a theoretical assessment.Social implicationsThis research may not have social implications.Originality/valueThis work is the sole work of authors that have not been communicated to any other journal before.

Career satisfaction antecedents of professional accounting returnees in international workplaces: an employee experience perspective

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nga Thi Thuy Ho ◽  
Hung Trong Hoang ◽  
Pi-Shen Seet ◽  
Janice Jones ◽  
Nhat Tan Pham
Keyword(s):  
Design Methodology ◽  
Career Satisfaction ◽  
Home Country ◽  
Well Being ◽  
Cross Cultural ◽  
Cultural Work ◽  
Content Type ◽  
Different Types ◽  
Employee Experience ◽  
Practical Implications

PurposeThe purpose of this study is to examine the determinants of career satisfaction of professional accounting returnees who have studied and/or worked abroad and then returned to work in different types of international workplaces in their home country.Design/methodology/approachA survey of professional accounting returnees in Vietnam was undertaken and multiple regression analysis was applied to test the proposed relationships.FindingsThis study finds that career satisfaction is affected by career fit, career sacrifice, types of international workplaces (domestically headquartered firms versus globally headquartered firms) and cross-cultural work readjustment. Further, cross-cultural work readjustment partially mediates the effect of career fit and career sacrifice on career satisfaction.Practical implicationsThe research provides the basis for designing career-related employee experiences to support career satisfaction of professional accounting returnees.Originality/valueThis study integrates dimensions of career embeddedness with cross-cultural work readjustment and employee experiences, which are normally studied separately, in different types of international workplaces. It contributes to the limited research on contributors to well-being in the form of career satisfaction among professional returnees in an emerging economy.

scholarly journals Mathematical model on distributed denial of service attack through Internet of things in a network

2019 ◽  
Vol 8 (1) ◽  
pp. 486-495 ◽  
Author(s):  
Bimal Kumar Mishra ◽  
Ajit Kumar Keshri ◽  
Dheeresh Kumar Mallick ◽  
Binay Kumar Mishra
Keyword(s):  
Mathematical Model ◽  
Internet Of Things ◽  
Equilibrium Points ◽  
Denial Of Service ◽  
Distributed Denial Of Service ◽  
Ddos Attacks ◽  
Denial Of Service Attack ◽  
Different Types ◽  
Service Attack ◽  
Iot Devices

Abstract Internet of Things (IoT) opens up the possibility of agglomerations of different types of devices, Internet and human elements to provide extreme interconnectivity among them towards achieving a completely connected world of things. The mainstream adaptation of IoT technology and its widespread use has also opened up a whole new platform for cyber perpetrators mostly used for distributed denial of service (DDoS) attacks. In this paper, under the influence of internal and external nodes, a two - fold epidemic model is developed where attack on IoT devices is first achieved and then IoT based distributed attack of malicious objects on targeted resources in a network has been established. This model is mainly based on Mirai botnet made of IoT devices which came into the limelight with three major DDoS attacks in 2016. The model is analyzed at equilibrium points to find the conditions for their local and global stability. Impact of external nodes on the over-all model is critically analyzed. Numerical simulations are performed to validate the vitality of the model developed.

scholarly journals Investigation on membrane fouling in ultrafiltration of latex solution

2021 ◽  
Author(s):  
Amira Abdelrasoul
Keyword(s):  
Mathematical Model ◽  
Molecular Weight ◽  
Power Consumption ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Operating Conditions ◽  
Specific Power ◽  
Pore Sizes ◽  
Wide Range ◽  
Different Types

The low-pressure membrane applications are considered to be the most effective and sustainable methods of addressing environmental problems in treating water and wastewater that meets or exceed stringent environmental standards. Nevertheless, membrane fouling is one of the primary operational concerns that is currently hindering a more widespread application of ultrafiltration (UF) with a variety of contaminants. Membrane fouling leads to higher operating costs, higher energy demand, reduced membrane life time, and increased cleaning frequency. As a consequence, an efficient and well-planned UF process is becoming a necessity for consistent and long-term monetary returns. Examining the source and mechanisms of foulant attachment to the membrane’s surface is critical when it comes to the research of membrane fouling and its potential practical implementation. A mathematical model was developed in this study in order to predict the amount of fouling based on an analysis of particle attachments. This model was developed using both homogeneous and heterogeneous membranes, with a uniform and non-uniform pore sizes for the UF of simulated latex effluent with a wide range of particle size distribution. The objective of this mathematical model was to effectively identify and address the common shortcomings of previous fouling models, and to account for the existing chemical attachments in membrane fouling. The mathematical model resulting from this study was capable of accurately predicting the mass of fouling retained by the membrane and the increase in transmembrane pressure (TMP). In addition, predictive models of fouling attachments were derived and now form an extensive set of mathematical models necessary for the prediction of membrane fouling at a given operating condition, as well as, the various membrane surface charges. Polycarbonate and Polysulfone flat membranes, with pore sizes of 0.05 μm and a molecular weight cut off of 60,000 respectively, were used in the experimental designs under a constant feed flow rate and a cross-flow mode in UF of the simulated latex paint effluent. The TMP estimated from the model agreed with the experimentally measured values at different operating conditions, mostly within 5.0 - 8.0 % error, and up to 13.0% error for the uniform, and non-uniform pore size membranes, respectively. Furthermore, different types of membranes with a variety of molecular weight cut-off (MWCO) values were tested so as to evaluate the accuracy of the models for a generalized application. In addition , a power consumption model, incorporating fouling attachment as well as chemical and physical factors in membrane fouling, was developed in order to ensure accurate prediction and scale-up. Innovative remediation techniques were likewise developed and applied in order to minimize membrane fouling, enhance the membrane performance, and save energy. Fouling remediation methodologies included the pre-treating of the latex effluent, so as to limit its fouling propensity by using different types of surfactants as cationic and anionic, in addition to the pH change. The antifouling properties of the membranes were improved through the implementation of the membrane pH treatment and anionic surfactant treatment. Increasing the ionic strength of latex effluent or enhancing the membrane surface hydrophilicity facilitated a significant increase in the cumulative permeate flux, a substantial decrease in the total mass of fouling, and a noticeable decrease in the specific power consumption.

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