The Analytical Approaches and Principles Used for the Purchases of Light Weight and Passenger Vehicles in a Saturated Market

This paper addresses the analytical questions surrounding the index of customers satisfaction level, and their differentiation into unit clusters in the light weight and passenger vehicles market.


Introduction
The purpose of this study as carried out by the Department of Road Transport Operations, Moscow State Automobile and Road Technical University (MADI), is to propose a set of principles, approaches and the basic methodological provisions directed towards the development, and practical implementation of tasks, aimed at solving the problems of assessment, forecasting, and optimizing the functioning of the inventory management systems of spare parts and materials in its specified area of business activity.

Material and methods
The practical implementation of the above-mentioned requires an intensive study, and the solving of the following sequentially interrelated set of problems: • carry out an analysis ofcustomer's satisfaction level index (U) (vehicle owners), and differentiate the highest satisfaction levels index into clusters in the light duty and passenger vehicle market (hereinafter referred to as "light weight vehicles" -LWV); • identify sales dynamics history of LWV, followed with subsequent modeling of sales forecast, both for all of the LWV brands introducedinto the Russian market, as well as the clusters with the largest consumer satisfaction index, followed by an assessment of the correlation between sales volumes and changes in economic situations; • highlighting the most represented brands of LWV, with the highest index of customer satisfaction, and a non reducible dynamics of volume introduced into the market for this type of vehicle group.
• with the aim of solving the problems of assessment, forecasting, and optimizing the functioning of the Inventory Management Systems (IMS) of spare parts and materials in its specified area of business activity, there is need for solving some set of problems focused on the following: • distinguish the make and models from previously formed clusters of represented makes of LWV and the identification of critical elements based on the level of efficiency and reliability which are subject to further analysis aimed at solving the problems of forecasting, and optimizing the functioning of the IMS; • obtaining, processing and conducting an analysis of the represented information on the dynamic intensity of the operation and the operational reliability index (with the identification of the necessary qualitative and quantitative indicators and parameters), followed by the formation of a failure flow chart of elements (aggregates, nodes, systems, parts) for the selected LWV.
• the development of an inventory management system of spare parts and materials in the specified area of business activity, optimizing and evaluating the operational efficiency for the selected elements and make of the LWV, taking into consideration the dynamics of introduction into the market, and the forecasted trends in economic conjuncture; • develop the functioning dynamic control principles of the IMS based on a group of limiting elements of reliability of the LWV for the selected model series of the LWV make under consideration.
Previously conducted studies by experts on issues relating to the modeling, forecasting and management of supplies of spare parts for the effective functioning of the production of technical service and repair (TS and R) of vehicles, considering the forecasting in demand of vehicle services, can be found in [2,[11][12][13][14][15][16][17].
Based on the framework of ongoing research and the results obtained, a series of publications is being envisaged on the above-mentioned stages of problem solving.

Theory
In accordance with the structure of the research presented above, the analysis of vehicle owners preferences introduced into the LWV market with selection of make with the highest level of customer satisfaction index was carried out on the first stage. For this purpose, the statistical information''Rating of the TOP-30 vehicle make with customer satisfaction index"by the analytical agency "AUTOSTAT" [1] was used. The analysis shows that, in general, there is a sufficiently a high customer satisfaction index of vehicles introduced into the LWV market (see fig. 1).
As an evaluation criteria, the following indicators characterizing: the vehicle as a whole; the assembly quality; corrosion resistance; noise insulation; physical appearance / design; the acceleration dynamics; smooth running; control and stability; clearance; ergonomics (comfort and convenience); efficiency of heating systems, ventilation and air conditioning; saloon and luggage compartment capacity; fuel consumption; maintenance cost and repair.
The processing of the above-mentioned information will make it possible in obtaining the following: • estimation indicators of the level of satisfaction and its fluctuations in the trust and tolerant boundaries; • plot a distribution pattern; • highlight the manufacturers -the leaders who are marketing their LWV.
where, u -satisfaction index of the LWV. Table 1 shows the corresponding estimated statistical indicators of satisfaction level of LWV owners.

Fig. 2. Differential function of the normal distribution f(u) of the satisfaction level of LWV
The processing of these statistical data was made possible with the use of known mathematical statistics and the theory of probability [3][4][5][6][7][8][9][10].
The analysis of the results presented in fig 1 and 2 At same time, within the control boundary for a given probability γ=0,9 for the range of a satisfaction level index, includes vehicle makes such as Lifan and Lexus (see. fig. 1).
For example, in the first group from Ū to [Ū+2σ(u)], there are such common vehicle make such as Audi (UAudi=85,7), which happens to be a direct competitor to makes as BMW, Land Rover, Lexus, Honda, Mercedes, Toyota, Volvo. An estimate of the probability of its belonging to the TOP-30 vehicle makes or brands for the normal distribution law U is determined from the following: where F(Z) -nominal distribution function; Zi -nominal random variable for the given index of satisfaction level for the considered LWV. Audifor The percentage of the above-mentioned LWV makes (BMW, Land Rover, Lexus, Honda, Mercedes, Toyota, Audi, Volvo) from the TOP-30 list is determined using the relationship below (4): where ×100%=0,19( or 19%) The graphical representation in the form of satisfaction rating of the above-mentioned LWV makes is shown in fig 3.   Fig. 3

Results
The analysis presented in Figure 3 helps to provides information on the estimated parameters of the mean square value Ū σp and the mean-square deviation σ(Ū σp ) of the satisfaction rating for above-mentioned LWV makes values equalling:

Conclusion
This ultimately allows the formation of a cluster LWV Makes with U 84, 73 br  (namely BMW, Land Rover, Lexus, Honda, Mercedes, Toyota, Audi), subject to further analysis in terms of market volume introduction and sales dynamics, by forecasting in the short and medium-term periods, allocation for further consideration of the most represented and critical the level of efficiency and reliability of a vehicle make and their elements (taking into consideration the intensity of operation and operational reliability), followed by the development of an inventory management system for spare parts, its optimization and evaluation of the efficiency of its functioning in its areas of business activity.
The problems as described will be discussed in subsequent series of publications.