• Communications for Statistical Applications and Methods
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• v.11 no.2
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• pp.227-233
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• 2004

This paper presents our work on constructing a model that is intended to predict the probability of attrition at specified points in time among customers of an insurance company. There are some difficulties in building a data-based model because a data set may contain possibly censored observations. In an effort to avoid such kind of problem, we performed logistic regression over specified time intervals while using explanatory variables to construct the proposed model. Then, we developed a Cox-type regression model for estimating the probability of attrition over a specified period of time using time-dependent explanatory variables subject to changes in value over the course of the observations.

• Communications for Statistical Applications and Methods
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• v.9 no.1
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• pp.271-280
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• 2002

Recently, many companies have applied data mining techniques to promote competitive power in the field of their business market. In this study, we address how data mining, that is a technique to enable to discover knowledge from a deluge of data, Is used in an executed project in order to support decision making of an enterprise. Also, we develope scoring model on customer attrition probability for automobile-insurance company using data mining techniques. The development of scoring model in domestic insurance is given as an example concretely.

• Journal of the military operations research society of Korea
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• v.28 no.2
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• pp.70-84
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• 2002

This paper deals with the attrition rate of major facility such as a particular building that is one of the most important target in the war time. In order to estimate the attrition rate, we use JAWS, WinJMEM which are programed by JTCG/ME of AMSAA and spreadsheet package which is able to assist the limitation of those programs and calculate all the procedure of this computation. This method uses the effectiveness index(El) which indicates the numerical measure of the effectiveness of a given weapon of a given target. The range error probable(REP) and the deflection error probable(DEP) in the ground plane also should be used. Those mean the measure of delivery accuracy of the weapon system. In this paper, it is improved that the El can be obtained from the regression analysis using the weight of the warhead explosive as the independent variable. It implies that we are able to obtain the El and the conditional probability of damage of the enemy weapon. After that, the single-sortie probability of damage can be computed using WinJMEM or another assistant program such as the spreadsheet package which shows the result immediately.

• Journal of the military operations research society of Korea
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• v.12 no.2
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• pp.22-36
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• 1986

The study is to design optimal aircraft allocation model for sufficing the required level of damage, minimizing attrition cost when the aircrafts attack the enemy's fixed target. When friendly aircraft attacks enemy target, the aircraft will suffer the loss due to the enemy's anti-aircraft weapons and aircraft. For this study, it is required that the probability of target damage by the type of aircraft, level of target damage and attrition cost are computed for the application of this model.

• Journal of the military operations research society of Korea
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• v.3 no.2
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• pp.119-134
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• 1977

The goal of this study is to determine which is the better bomb; a general purpose bomb or a special bomb, from the point of view of cost-effectiveness of air munitions. What we call the special bomb is a laser guided bomb which adds a guidance control unit on the head of a general purpose bomb. Althrough their characteristics of explosion are the same, their effectivenesses are very defferent due to their probability of hitting the targets. Now, in order to measure their relative a effectiveness, we could select various enemy targets such as runway, radar, and then Ive could also calculate requirments of both bombs and firghter aircraft sorties according to the desired damage level of each target, Following above steps, we can derive the total costs and compare effectiveness. As a results of this study, when the attrition rate of aircraft is under $1.1\%$, the general purpose bomb is better than the laser guided bomb. Above $1.1\%$ attrition rate, we could say that luser guided bomb is the most economical bomb.

• Journal of Korean Society of Transportation
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• v.18 no.6
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• pp.63-75
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• 2000

Stated Preference (SP) data has been regarded as more useful than Revealed Preference (RP) data, because researchers can investigate the respondents\` Preference and attitude for a traffic condition or a new traffic system by using the SP data. However, the SP data has two bias: the first one is the bias inherent in SP data and the latter one is the attrition bias in SP panel data. If the biases do not corrected, the choice model using SP data may predict a erroneous future demand. In this Paper, six route choice models are constructed to deal with the SP biases, and. these six models are classified into cross-sectional models (model I∼IH) and dynamic models (model IV∼VI) From the six models. some remarkable results are obtained. The cross-sectional model that incorporate RP choice results of responders with SP cross-sectional model can correct the biases inherent in SP data, and also the dynamic models can consider the temporal variations of the effectiveness of state dependence in SP responses by assuming a simple exponential function of the state dependence. WESML method that use the estimated attrition probability is also adopted to correct the attrition bias in SP Panel data. The results can be contributed to the dynamic modeling of SP Panel data and also useful to predict more exact demand.

• Journal of the Korean Statistical Society
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• v.6 no.1
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• pp.65-76
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• 1977

The relative importance of single-shot kill probabilities, rates of fire, weapon allocation strategies, and the size of initial force in warfare between two force with heterogeneous multiple weapon systems are considered by examining their effect on a natural measure of effectiveness, the expected number of survivors. Attrition equations are derived via stochastic formulation to represent the mean course of battle having an underlying probability distribution. It is assumed that each side uses indirect area fires. Level of intelligence activities are reflected in the availability of spontaneous information on the current enemy status. Depending on the availability of the information on the current enemy status, each participatory unit may follow 1) a prescribed attack pattern (fraction of the available units assigned to various enemy targets) or 2) an adaptive attack pattern depending on the enemy status at that time. Conditions for possible stalemate are discussed.

• Journal of the military operations research society of Korea
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• v.17 no.2
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• pp.44-53
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• 1991

This paper is aimed to develop a Lanchester type combat model for the direct-fire engagement. This model incorporates number of combatants, inter-firing time, detection time by movement, detection probability by the signature of fire, where the inter-firing time and the detection time are assumed to follow a negative exponential distribution. The approach to modeling is as follows : in the process of an engagement, a combatant takes one of the states('observing' state or 'firing' state), a combatant is initially in the observing state, if the combatant detects a target, he changes his state from 'observing' to 'firing' and will cause attrition to the opposing forces. Thus this transition mechanism is embodied into the differential equation form with each transition rate. A limited examination of the validity has been conducted by comparison with the Monte-Carlo simulation model 'BAGSIM', and with a traditional Deterministic Lanchester model.

• Journal of the Korean housing association
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• v.23 no.1
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• pp.55-66
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• 2012

Present study investigates on the impact of resources and characteristics of the tenure choice for divorced women in Korea. The authors utilize the micro data from the Korea Census (2% sample) provided by the National Statistical Office. The authors apply the bivariate probit model to eliminate selection bias that could incur due to sample selectivity, from a chain of marital disruption and tenure choices. This study starts with a descriptive explanation of homeownership after divorce from 1985 to 2005. It concluded that divorce results in a substantial attrition of homeownership. The authors found that out for many women, divorce initiates a process of downward mobility on the housing ladder. The probability to own housing is much lower for divorced women than for women who are not divorced. The present study concludes by suggesting some policy implications for divorced women who have limited access to housing stability. The authors also suggest some future studies that can compensate the empirical limitations of the present study.

• The Journal of Bigdata
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• v.8 no.1
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• pp.23-34
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• 2023

Nowadays, the Designated Driver Services employ dynamic pricing, which adapts in real-time based on nearby driver availability, service user volume, and current weather conditions during the user's request. The uncertain volatility is the main cause of price increases, leading to customer attrition and service refusal from driver. To make a good Designated Driver Services, development of a demand forecasting model is required. In this study, we propose developing a demand forecasting model using data from the Designated Driver Service by considering normal and peak periods, such as rush hour and rush day, as prior knowledge to enhance the model performance. We propose a new methodology called Time-Series with Conditional Probability(TSCP), which combines conditional probability and time-series models to enhance performance. Extensive experiments have been conducted with real Designated Driver Service data, and the result demonstrated that our method outperforms the existing time-series models such as SARIMA, Prophet. Therefore, our study can be considered for decision-making to facilitate proactive response in Designated Driver Services.