Udjianna S. Pasaribu

Maintenance Service Contracts for Equipment Sold with Two Dimensional Warranties

Abstract HeThis paper deals with maintenance service contracts for equipment (such as dump trucks) sold with two dimensional warranties. We consider a situation where an agent offers several maintenance contract options and the owner of the equipment has to select the optimal option. As the availability of the equipment is a critical measure for attaining the owner’s business objectives, the maintenance contract options offered need to ensure a high availability of the equipment. We study three maintenance service options considering the availability target from both the owner and OEM point of views and use a non-cooperative game formulation to determine the optimal price structure (i.e., the contract price and repair cost) for the OEM and the optimal contract option for the owner.

Performance-based maintenance contract for equipments used in mining industry

In this paper, we study performance based maintenance contracts for dump trucks operated in a mining industry. The service contract is characterised by two dimensional limits - one limit representing age and the other limit usage. In a performance based service contract uses an attractive incentives to motivate the the agent to increase the equipments performance beyond the target, and this in turn gives benefit for both the owner of the trucks and the Agent of service contract. In this paper, we study performance based maintenance service contracts for equipment used in a mining industry and the equipment is sold with two dimensional warranties and the perfomances considered includes availability and safety measures. We consider a situation where an agent offers several service contract options and the owner of equipment has to select the optimal option. We obtain the optimal strategy (pricing structure) for the agent and the optimal option for the owner using a stackelberg game formulation in which the agent is as a leader and the owner as a follower.

Two Dimensional Maintenance Contracts for a Fleet of Dump Trucks Used in Mining Industry

In this paper, we study two dimensional maintenance contracts for a fleet of dump trucks operated in a mining industry. The two-dimensional contract is charaterised by two parameters (i.e. age and usage limits) which define a region. Two different shapes of the contract region are studied, where one region favors the customer, and the other the service provider. The maintenance service contracts studied is the performance based contract which offers incentives to motivate a service provider (an agent) to increase the equipment’s performance beyond the target. This in turn gives benefit for both the owner of the trucks and the agent of service contract. The decision problem under study is that an agent offers several two dimensional service contract options and the owner of the trucks has to select the optimal option. We use a Nash game theory formulation in order to obtain a win-win solution – i.e. the optimal strategy (pricing structure) for the agent and the optimal option for the owner.

An ARCH model the electric power of extra high voltage (EHV) transmission substation forecasting in Cawang, Jakarta, Indonesia

An ARCH forecasting model for electric power demand of an EHV is proposed in this work. The power demand in EHV substation, Jakarta, Indonesia which passed through Cawang substation is continuously changed in values either normally or drastically. These electric demands were measured every 30 minutes so that there are 48 different values of electric demand that pass through a substation for one day. To distribute the power to the customers, PT Perusahaan Listrik Negara (PLN) has to determine which power plant will be used with the most optimum route and minimum operations budget. For that purpose, an ARCH modeling was applied so that the forecast power demand could be estimated. This model is applied to unveil the heteroscedasticity character of residuals with inconstant variance. In this work, MATLAB software and NUMXL were used for parameters estimation of model identification. As a result, it turns out that convergent parameter values obtained when 28 data observations were used. Therefore, the forecasting of electric power was generated in order to forecast up to ten steps ahead. This forecasting of the electric power could provide extensive and valuable information of electric power to PLN so that electric route and related budget can be optimized.

Performance-based maintenance contract for a fleet of dump trucks used in mining industry

In this paper, we study two dimensional maintenance contracts for a fleet of dump trucks operated in a mining industry. We consider performance based service contracts which offer attractive incentives to motivate a service provider (an agent) to increase the equipments performance beyond the target. This in turn gives benefit for both the owner of the trucks and the Agent of service contract. The situation under study is that an agent offers several two dimensional service contract options and the owner of the trucks needs to select the optimal option. We use a stackelberg game formulation in which the agent is as a leader and the owner as a follower to obtain the optimal strategy (pricing structure) for the agent and the optimal option for the owner.

The stationarity of generalized STAR(2;λ1,λ2) process through the invers of autocovariance matrix

In this paper, we apply the Invers of Autocovariance Matrix (IAcM) to investigate the process stationarity of the Generalized STAR model. In particular, we consider the second order of Generalized STAR (GSTAR(2;λ1,λ2)) processes. For that purpose, we derive the use of IAcM for the first order of GSTAR (GSTAR(1;λ1)) processes briefly. We move forward to the second order by following two important steps i.e. investigate the relevance between the sum square of errors and IAcM, and formulate the elements of IAcM as the function of autoregressive parameters and spatial weights. We obtain a definite positive IAcM whose size is twice the IAcM’s size of GSTAR(1;λ1). We acquire the GSTAR(2;λ1,λ2) process is stationary if all determinants of the IAcM’s leading principal submatrices are positive. Furthermore we find that the stationary condition obtained from the IAcM is stronger than from the characteristic polynomial of parameter matrix.

Study of behavior and determination of customer lifetime value(CLV) using Markov chain model

Customer Lifetime Value or CLV is a restriction on interactive marketing to help a company in arranging financial for the marketing of new customer acquisition and customer retention. Additionally CLV can be able to segment customers for financial arrangements. Stochastic models for the fairly new CLV used a Markov chain. In this model customer retention probability and new customer acquisition probability play an important role. This model is originally introduced by Pfeifer and Carraway in 2000 [1]. They introduced several CLV models, one of them only involves customer and former customer. In this paper we expand the model by adding the assumption of the transition from former customer to customer. In the proposed model, the CLV value is higher than the CLV value obtained by Pfeifer and Caraway model. But our model still requires a longer convergence time.

Non-stationary model for rice prices in Bandung, Indonesia

A non-stationary forecasting model for rice prices is proposed in this paper. A daily rice price has two behaviors i.e. normal and spiky. To encounter both behaviors, non-stationary model has been applied. From various type of non-stationary model, the simple one which contains ARIMA model and GARCH model are applied. The ARIMA model is applied to catch the linear relationship of non-stationary data through differencing. On the other hand, the GARCH model is applied to unveil the heteroscedastic character of residuals with inconstant variance, a generalization of ARCH models. However, due to its limitation of recent GARCH model, MATLAB software and NUMXL, additional software on Excel, shall be used for parameters estimation of identified models. Hereafter, the forecasting of normal and spike patterns of rice prices are generated to form an overall price up to one day-ahead. As a result, this forecasting of the rice price could provide extensive and valuable information for rice market stakeholders.

The use of IAcM to identify stationarity of the generalized STAR models

A new approach of identifying stationarity of the space-time processes through the Invers of Autocovariance Matrix (IAcM) is proposed. In particular, we consider the first order Generalized Space Time Autoregressive (GSTAR(1;1)) model. This model is considered to be more representative model in space-time modeling due to its realistic assumption on the uniqueness of spatial location. We are exploring the behavior of the IAcM on behalf of the process stationarity. The stationary condition is a must for GSTAR process to be able to apply in space-time modeling. We obtain that the IAcM may be stated as the function of autoregressive parameters and weight spatial. For the confirmation we carry out numerical analysis for various autoregressive parameter matrices and weight matrices. Through some simulations, we illustrate how significant the autoregressive parameters and weight spatial matrices influence the behavior of the IAcM.

A maintenance service contract for a warranted product

In this paper, we investigate a maintenance service contract for a warranted product carried out by the Original Equipment Manufacturer (OEM). The model was developed under the assumption that there are one consumer and one service provider who is the OEM. This is typically applied to the situation where the OEM is the only service provider such as in the mining industry. From the OEM point of view, two contract options were considered, they are: the OEM carried out all repairs and preventive maintenance activities; the OEM carries out failure and the customer undertakes in house preventive maintenance actions. The model uses a non-cooperative game formulation by maximizing expected profits. We use a linear function of failure intensity to consider a product with increasing failure intensity. We obtain the pricing structure in the contract. And for the customer, they can choose the optimal option under the term of contract.