Representation of replacement rules in the form of a matrix

2016 ◽  
Vol 22 (2) ◽  
pp. 164-179
Author(s):  
Sergey Golovin
Keyword(s):  
Mathematical Models ◽  
Cost Structure ◽  
Verbal Description ◽  
System Component ◽  
Content Type ◽  
Maintenance Program ◽  
Repair Costs ◽  
System Components ◽  
The Matrix ◽  
The Cost

Purpose – The purpose of this paper is to represent replacement policies (rules) in the form of a matrix. Visualization of replacement rules is useful for maintenance records. Matrix representation is more effective than the verbal description usually provided, as it allows better understanding of the specifics of the different replacement rules without careful research of their mathematical models. Design/methodology/approach – This approach employs mathematical models to investigate the simple conditions (requirements) for replacement of system component with illustrative examples. When comparing the different replacement rules a cost structure is applied to takes into account the nature and technology of disassembly assembly actions for the repair unit. Findings – Representation of replacement rules in the matrix form is useful when describing planned replacement models, opportunity replacement models, group replacement models and others, as well as computer modeling of the renewal process. Forming simple conditions for the replacement of system components ensures the total average repair cost is minimized. These conditions can be applied in the early stages of creating a maintenance program for the machine. Practical implications – Replacement matrices can be specified in a technical manual for maintenance of machines to achieve reliable operation and to reduce repair costs. Replacement matrices can be put into practical use for maintenance records and may be included in the maintenance procedures library of CMMSs. Developed in the paper, the replacement matrix, the conditions for replacement of system components and the cost structure will help engineers to make decisions at the time of repair for assembly units. Originality/value – Proposed in the paper is a new approach to the visualization of the replacement rules and cost structure which simplifies the analysis of options for repair actions. The proposed technique contributes to the record of maintenance actions and the decision making process for replacement.

Economic consequences of consumer repair strategies for electrical household devices

2019 ◽  
Vol 33 (4) ◽  
pp. 747-767 ◽  
Author(s):  
Jan Brusselaers ◽  
Ellen Bracquene ◽  
Jef Peeters ◽  
Yoko Dams
Keyword(s):  
Life Cycle Cost ◽  
Economic Consequences ◽  
Future Research ◽  
Data Sets ◽  
Annual Life Cycle ◽  
Content Type ◽  
Repair Strategy ◽  
Repair Costs ◽  
The Cost ◽  
Practical Implications

Purpose The purpose of this paper is to investigate to what extent a consumer’s repair strategy impacts the annual costs of ownership of a washing machine and two types of vacuum cleaner. Design/methodology/approach The annual cost of ownership is determined by calculating the annual life cycle cost (LCC) for the respective devices. The annual LCCs of the different scenarios allow a comparison of the different repair strategy options. A Monte Carlo simulation is run to introduce parameter variability. The device’s failure rate is estimated by a combination of data sets on the devices’ performance. Findings Results demonstrate that the repair of the devices considered is a more favourable option over replacement. A consumer who aims for the lowest annual LCC should allow for a high number of repairs per device, without putting a maximum on the cost per repair. However, the consumer should become more cautious when a device approaches the end of its expected lifetime. Finally, the purchase of warranty can be interesting when the warranty covers a sufficiently long proportion of the device’s (expected) lifetime and when its cost does not exceed a threshold proportion of the initial purchase price. Research limitations/implications The costs for repair might be overestimated. Future research can focus on the reduction of repair costs following self-repair. Practical implications The results provide strong arguments in favour of repair instead of replacement of broken devices. Originality/value This is the first research to quantify the influence of consumer behaviour in the context of repair of devices on the ownership costs of these devices.

Oil-cut deal threatened by exempt nations and by shale

2017 ◽  
Keyword(s):  
Market Share ◽  
Oil Sands ◽  
Cost Structure ◽  
Content Type ◽  
Oil Drilling ◽  
The Cost ◽  
Economic Outlook

Subject OPEC-non-OPEC deal compliance Significance Strong compliance with production cut allocations among OPEC members is being balanced by increases from exempt members Libya and Nigeria. There has also been a rise in Iranian output, allowed under the terms of the agreement. Higher prices have added impetus to the revival of US shale output. Impacts Shale drilling costs have fallen, and productivity has risen, making US shale expansion and contraction balance at 50 dollars per barrel. US shale will take market share from high-cost output such as oil sands rather than OPEC, assisting the positive US economic outlook. The shift in the cost structure of oil output will boost investment in non-US shale, while non-US, non-OPEC oil drilling will struggle.

A cost minimisation model for system reliability allocation

2019 ◽  
Vol 36 (9) ◽  
pp. 1620-1643 ◽  
Author(s):  
Omkarprasad S. Vaidya ◽  
L. Ganapathy ◽  
Sushil Kumar
Keyword(s):  
Optimization Problem ◽  
Cost Optimization ◽  
Optimal Solution ◽  
System Component ◽  
Lagrangian Multiplier ◽  
Step Size ◽  
Exponential Relationship ◽  
Content Type ◽  
In Series ◽  
The Cost

Purpose The purpose of this paper is to consider a nonlinear problem of minimizing the cost of providing reliable systems. The authors assume that the system consists of several components in series, and for each such component, the cost of the component increases exponentially with its reliability. Design/methodology/approach In order to solve this nonlinear optimization problem, the authors propose two approaches. The first approach is based on the concept of adjusting the reliability of a pair of components to minimize the cost of the system. The authors call this procedure as reliability adjustment routine (RAR). Proofs of optimality and convergence for the proposed model are also provided. The second approach solves the problem by using a Lagrangian multiplier. A procedure is developed to obtain the maximum step size to achieve the desired optimal solution in minimum iterations. Proposed approaches are efficient and give exact solutions. Findings Proposed methods enable a decision maker to allocate reliability to the components in series while minimizing the total cost of the system. The developed procedures are illustrated using a numerical example. Although an exponential relationship between the component cost and reliability is assumed, this can be extended to various other nonlinear distributions. Originality/value This cost optimization problem, subject to system component reliability values, assumes the near practical nonlinear pattern of cost vs reliability. Such problems are complex to solve. The authors provide a unique approach called RAR to solve such convoluted problems. The authors also provide an approach to solve such problems by using a Lagrangian multiplier method. Various proofs have been worked out to substantiate the work.

On Some Properties of Semi-rings

2018 ◽  
pp. 35-50
Author(s):  
A. I. Belousov
Keyword(s):  
Linear Equations ◽  
Oriented Graph ◽  
Theoretical Computer Science ◽  
Alternative Methods ◽  
Main Role ◽  
Cost Matrix ◽  
Sequential Elimination ◽  
The Matrix ◽  
Systems Of Linear Equations ◽  
The Cost

The main objective of this paper is to prove a theorem according to which a method of successive elimination of unknowns in the solution of systems of linear equations in the semi-rings with iteration gives the really smallest solution of the system. The proof is based on the graph interpretation of the system and establishes a relationship between the method of sequential elimination of unknowns and the method for calculating a cost matrix of a labeled oriented graph using the method of sequential calculation of cost matrices following the paths of increasing ranks. Along with that, and in terms of preparing for the proof of the main theorem, we consider the following important properties of the closed semi-rings and semi-rings with iteration.We prove the properties of an infinite sum (a supremum of the sequence in natural ordering of an idempotent semi-ring). In particular, the proof of the continuity of the addition operation is much simpler than in the known issues, which is the basis for the well-known algorithm for solving a linear equation in a semi-ring with iteration.Next, we prove a theorem on the closeness of semi-rings with iteration with respect to solutions of the systems of linear equations. We also give a detailed proof of the theorem of the cost matrix of an oriented graph labeled above a semi-ring as an iteration of the matrix of arc labels.The concept of an automaton over a semi-ring is introduced, which, unlike the usual labeled oriented graph, has a distinguished "final" vertex with a zero out-degree.All of the foregoing provides a basis for the proof of the main theorem, in which the concept of an automaton over a semi-ring plays the main role.The article's results are scientifically and methodologically valuable. The proposed proof of the main theorem allows us to relate two alternative methods for calculating the cost matrix of a labeled oriented graph, and the proposed proofs of already known statements can be useful in presenting the elements of the theory of semi-rings that plays an important role in mathematical studies of students majoring in software technologies and theoretical computer science.

Study on high-temperature wear and mechanism of Al-Si/graphite composites prepared by the die-casting process

2020 ◽  
Vol 72 (10) ◽  
pp. 1153-1158 ◽  
Author(s):  
Yafei Deng ◽  
Xiaotao Pan ◽  
Guoxun Zeng ◽  
Jie Liu ◽  
Sinong Xiao ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Peer Review ◽  
Die Casting ◽  
Casting Machine ◽  
Injection Pressure ◽  
Casting Process ◽  
Matrix Alloy ◽  
Content Type ◽  
The Matrix

Purpose This paper aims to improve the tribological properties of aluminum alloys and reduce their wear rate. Design/methodology/approach Carbon is placed in the model at room temperature, pour 680°C of molten aluminum into the pressure chamber, and then pressed it into the mold containing carbon felt through a die casting machine, and waited for it to cool, which used an injection pressure of 52.8 MPa and held the same pressure for 15 s. Findings The result indicated that the mechanical properties of matrix and composite are similar, and the compressive strength of the composite is only 95% of the matrix alloy. However, the composite showed a low friction coefficient, the friction coefficient of Gr/Al composite is only 0.15, which just is two-third than that of the matrix alloy. Similarly, the wear rate of the composite is less than 4% of the matrix. In addition, the composite can avoid severe wear before 200°C, but the matrix alloy only 100°C. Originality/value This material has excellent friction properties and is able to maintain this excellent performance at high temperatures. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2019-0454/

The cost-effectiveness of insulin analogs and regular insulin for diabetes control: a case study in Iran

2020 ◽  
Vol 33 (4/5) ◽  
pp. 323-331
Author(s):  
Mohsen pakdaman ◽  
Raheleh akbari ◽  
Hamid reza Dehghan ◽  
Asra Asgharzadeh ◽  
Mahdieh Namayandeh
Keyword(s):  
Cost Effectiveness ◽  
Cost Effective ◽  
Regular Insulin ◽  
Diabetes Control ◽  
Diabetic Patients ◽  
Insulin Analogs ◽  
Content Type ◽  
Patients With Diabetes ◽  
The Government ◽  
The Cost

PurposeFor years, traditional techniques have been used for diabetes treatment. There are two major types of insulin: insulin analogs and regular insulin. Insulin analogs are similar to regular insulin and lead to changes in pharmacokinetic and pharmacodynamic properties. The purpose of the present research was to determine the cost-effectiveness of insulin analogs versus regular insulin for diabetes control in Yazd Diabetes Center in 2017.Design/methodology/approachIn this descriptive–analytical research, the cost-effectiveness index was used to compare insulin analogs and regular insulin (pen/vial) for treatment of diabetes. Data were analyzed in the TreeAge Software and a decision tree was constructed. A 10% discount rate was used for ICER sensitivity analysis. Cost-effectiveness was examined from a provider's perspective.FindingsQALY was calculated to be 0.2 for diabetic patients using insulin analogs and 0.05 for those using regular insulin. The average cost was $3.228 for analog users and $1.826 for regular insulin users. An ICER of $0.093506/QALY was obtained. The present findings suggest that insulin analogs are more cost-effective than regular insulin.Originality/valueThis study was conducted using a cost-effectiveness analysis to evaluate insulin analogs versus regular insulin in controlling diabetes. The results of study are helpful to the government to allocate more resources to apply the cost-effective method of the treatment and to protect patients with diabetes from the high cost of treatment.

scholarly journals Comparison of LPWAN Technologies: Cost Structure and Scalability

2021 ◽  
Author(s):  
Mohammad Istiak Hossain ◽  
Jan I. Markendahl
Keyword(s):  
Communication Technology ◽  
Service Providers ◽  
Communication Technologies ◽  
Cost Structure ◽  
Small Scale ◽  
Area Network ◽  
Wide Area Network ◽  
Generic Framework ◽  
Cost Efficient ◽  
The Cost

AbstractSmall-scale commercial rollouts of Cellular-IoT (C-IoT) networks have started globally since last year. However, among the plethora of low power wide area network (LPWAN) technologies, the cost-effectiveness of C-IoT is not certain for IoT service providers, small and greenfield operators. Today, there is no known public framework for the feasibility analysis of IoT communication technologies. Hence, this paper first presents a generic framework to assess the cost structure of cellular and non-cellular LPWAN technologies. Then, we applied the framework in eight deployment scenarios to analyze the prospect of LPWAN technologies like Sigfox, LoRaWAN, NB-IoT, LTE-M, and EC-GSM. We consider the inter-technology interference impact on LoRaWAN and Sigfox scalability. Our results validate that a large rollout with a single technology is not cost-efficient. Also, our analysis suggests the rollout possibility of an IoT communication Technology may not be linear to cost-efficiency.

Fatigue behavior of precipitation strengthened Cu–Ni–Si alloy modified by Cr and Zr addition

2020 ◽  
Vol 11 (6) ◽  
pp. 861-873
Author(s):  
Ş. Hakan Atapek ◽  
Spiros Pantelakis ◽  
Şeyda Polat ◽  
Apostolos Chamos ◽  
Gülşah Aktaş Çelik
Keyword(s):  
Design Methodology ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Lower Stress ◽  
Content Type ◽  
Hardened Alloy ◽  
Zr Addition ◽  
Nucleation Sites ◽  
The Matrix ◽  
Lower Stress Level

Purpose The purpose of this paper is to investigate the fatigue behavior of precipitation-strengthened Cu‒2.55Ni‒0.55Si alloy, modified by the addition of 0.25 Cr and 0.25 Zr (wt%), using mechanical and fractographical studies to reveal the effect of microstructural features on the fracture. Design/methodology/approach For strengthening, cast and hot forged alloy was subjected to solution annealing at 900°C for 60 min, followed by quenching in water and then aging at 490°C for 180 min. Precipitation-hardened alloy was exposed to fatigue tests at R=−1 and different stress levels. All fracture surfaces were examined within the frame of fractographical analysis. Findings Fine Ni-rich silicides responsible for the precipitation strengthening were observed within the matrix and their interactions with the dislocations at lower stress level resulted in localized shearing and fine striations. Although, by the addition of Cr and Zr, the matrix consisted of hard Ni, Zr-rich and Cr-rich silicides, these precipitates adversely affected the fatigue behavior acting as nucleation sites for cracks. Originality/value These findings contribute to the present knowledge by revealing the effect of microstructural features on the mechanical behavior of precipitation-hardened Cu‒Ni‒Si alloy modified by Cr and Zr addition.

Evaluating the cost and benefits of earthquake protection of buildings

2018 ◽  
Vol 11 (2) ◽  
pp. 263-278 ◽  
Author(s):  
Benedetto Manganelli ◽  
Marco Vona ◽  
Pierfrancesco De Paola
Keyword(s):  
Real Estate ◽  
Seismic Risk ◽  
Risk Mitigation ◽  
Tax Incentives ◽  
Seismic Retrofitting ◽  
Content Type ◽  
Seismic Risk Mitigation ◽  
The Cost ◽  
Earthquake Protection ◽  
Real Estate Assets

Purpose The purpose of this study is the evaluation of the cost and benefits of earthquake protection of buildings to verify whether the legislative push, through tax incentives, will produce results and lead to a redevelopment of private real estate assets. Design/methodology/approach Through contingent valuation, this research aims to measure the propensity of homeowners to invest in the seismic security of their properties. The sample of homeowners was selected in a southern Italy city, which was characterized by a medium-high seismic hazard. The willingness to pay, once made independent from the family income, was compared with the actual cost of a seismic retrofitting technique to assess its cost-effectiveness. Findings The analysis developed on an example case shows that the economic sustainability of the intervention is only verified when considering the current tax incentives for this type of intervention. Practical implications Choosing to introduce a system to compulsory insurance against seismic risk could certainly be a strong incentive for the implementation of retrofitting interventions on private real estate assets. In this direction, investigations like this can be fundamental to establish the fair risk premium. Originality/value The need for effective seismic risk mitigation policies is also based on the growing awareness of the, often fatal, effects of seismic events, emphasized by the recent medium and high intensity events that hit Italy. The issue of the security of residential buildings is therefore a very topical issue in view of their high seismic vulnerability and the vast number of buildings requiring major seismic retrofitting. Therefore, the propensity of owners to intervene in improving the seismic performance of their properties can be crucial in seismic risk mitigation.

The impact of labor freedom on geographic cost of living differentials

2017 ◽  
Vol 6 (3) ◽  
pp. 385-395
Author(s):  
Richard Cebula ◽  
James E. Payne ◽  
Donnie Horner ◽  
Robert Boylan
Keyword(s):  
Labor Market ◽  
State Level ◽  
The State ◽  
Annual Data ◽  
Significant Finding ◽  
Cost Of Living ◽  
Content Type ◽  
The Usa ◽  
The Cost ◽  
The Impact

Purpose The purpose of this paper is to examine the impact of labor market freedom on state-level cost of living differentials in the USA using cross-sectional data for 2016 after allowing for the impacts of economic and quality of life factors. Design/methodology/approach The study uses two-stage least squares estimation controlling for factors contributing to cost of living differences across states. Findings The results reveal that an increase in labor market freedom reduces the overall cost of living. Research limitations/implications The study can be extended using panel data and alternative measures of labor market freedom. Practical implications In general, the finding that less intrusive government and greater labor freedom are associated with a reduced cost of living should not be surprising. This is because less government intrusion and greater labor freedom both inherently allow markets to be more efficient in the rationalization of and interplay with forces of supply and demand. Social implications The findings of this and future related studies could prove very useful to policy makers and entrepreneurs, as well as small business owners and public corporations of all sizes – particularly those considering either location in, relocation to, or expansion into other markets within the USA. Furthermore, the potential benefits of the National Right-to-Work Law currently under consideration in Congress could add cost of living reductions to the debate. Originality/value The authors extend the literature on cost of living differentials by investigating whether higher amounts of state-level labor market freedom act to reduce the states’ cost of living using the most recent annual data available (2016). That labor freedom has a systemic efficiency impact on the state-level cost of living is a significant finding. In our opinion, it is likely that labor market freedom is increasing the efficiency of labor market transactions in the production and distribution of goods and services, and acts to reduce the cost of living in states. In addition, unlike previous related studies, the authors investigate the impact of not only overall labor market freedom on the state-level cost of living, but also how the three sub-indices of labor market freedom, as identified and measured by Stansel et al. (2014, 2015), impact the cost of living state by state.

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