Mining Bad Credit Card Accounts from OLAP and OLTP

Credit card companies classify accounts as a good or bad based on historical data where a bad account may default on payments in the near future. If an account is classified as a bad account, then further action can be taken to investigate the actual nature of the account and take preventive actions. In addition, marking an account as "good" when it is actually bad, could lead to loss of revenue - and marking an account as "bad" when it is actually good, could lead to loss of business. However, detecting bad credit card accounts in real time from Online Transaction Processing (OLTP) data is challenging due to the volume of data needed to be processed to compute the risk factor. We propose an approach which precomputes and maintains the risk probability of an account based on historical transactions data from offline data or data from a data warehouse. Furthermore, using the most recent OLTP transactional data, risk probability is calculated for the latest transaction and combined with the previously computed risk probability from the data warehouse. If accumulated risk probability crosses a predefined threshold, then the account is treated as a bad account and is flagged for manual verification.Comment: Conference proceedings of ICCDA, 201

Applying and Evaluating Models to Predict Customer Attrition Using Data Mining Techniques

As competition intensifies, retaining customers becomes one of the most serious challenges facing customer service providers. Customer attrition prediction models hold great promise as powerful tools for enhancing customer retention. Several statistical methods have been applied to develop models predicting customer attrition. Yet little research is done on the relative performance of models developed by different methods. The lack of knowledge about the performance of various prediction models is more pronounced due to the nonlinear nature of the combined causes of attrition (such as switching to another provider or canceling a service). The development of data mining techniques has made the comparison of prediction power of different models more efficient and easier. In this article we demonstrate how to use data mining techniques and software to fit and compare different customer attrition prediction models, using data from a major telecom service provider

Mining and residential development interact to produce highly impaired stream conditions in an intensively mined Appalachian watershed

Large scale surface mining in southern West Virginia causes significant alteration of headwater stream networks. It is unclear, however, the extent to which mining interacts with other stressors to determine physical, chemical, and biological conditions in aquatic systems downstream. Through a watershed scale assessment of Pigeon Creek, the specific objectives of this study were to: (1) quantify the direct and interactive effects of mining and residential development on in-stream conditions; and (2) identify landscape thresholds above which biological impairment occurs. Our results indicate high levels of impairment to habitat, water quality, and benthic invertebrate communities within this watershed. Statistical analyses indicate that degraded conditions were linked to both mining and residential development; however, residential development appeared to exhibit a stronger individual effect. Both mining and residential development resulted in a significant decrease in sensitive taxa. The impacts associated with residential development, however, also resulted in the proliferation of tolerant taxa. Both mining and residential development resulted in significant alterations to water chemistry, primarily through increases in dissolved ion concentrations and specific conductance. Changes in water quality resulting from mining, however, were more acute. Conversely, residential development resulted in more acute alterations to physical habitat, primarily through decreases in habitat complexity. Our results further suggest that the individual impacts associated with mining and residential development are additive, leading to highly degraded conditions downstream. The combined effects of mining and residential development were almost always worse than the individual effects of mining, but never worse than the individual effects of residential development. Thus, residential development appears to be the limiting factor in determining ecosystem impairment. Lastly, several community metrics exhibited potential threshold responses to relatively low levels of both total mining (∼25%) and parcel density (∼14 parcels/km 2). These change points corresponded to conductivities of approximately 100 uS/cm and 60 uS/cm, respectively. This study shows that effectively managing impacts from new mine development and watershed restoration efforts must address the prevalence of non-mining related impacts throughout this watershed

Poverty and Mortality Disparities in Central Appalachia: Mountaintop Mining and Environmental Justice

Objectives. This study investigated the associations between poverty rates, Appalachian mountaintop coal mining, and age-adjusted total mortality rates to determine if persons exposed to this form of mining experience greater poverty and higher death rates compared to other types of mining or other areas of Appalachia. Methods. Mortality rates, poverty rates, Appalachian designation and mining activity were examined for counties in Kentucky, Tennessee, Virginia and West Virginia (N=403). Linear least squares models tested for annual group differences from 2000-2007 in total and child poverty, and total mortality, based on mining type and Appalachian location. Nested linear models accounting for state-level effects were used to determine whether mountaintop mining and poverty were associated with mortality rates controlling for other risks. Results. Mountaintop mining areas had significantly higher mortality rates, total poverty rates and child poverty rates every year compared to other referent counties of these states. Both poverty and mountaintop mining were independently associated with age-adjusted mortality rates in nested models. Conclusions. Persons living in MTM areas experience persistently elevated poverty and mortality rates. Higher mortality is independently associated with both poverty and MTM, the latter effect suggestive of a possible environmental contribution from mining activities. Efforts to reduce longstanding health disparities in Appalachia must focus on those areas where disparities are concentrated: the Appalachian coalfields

Experimental studies on the shear resistance of original coal-shale joint

Purpose. Experimental study and theoretical modeling of the shear resistance of original coal-shale joint. Methods. A two-segment model was developed to describe the shear resistance-shear displacement curves obtained from the direct shear tests of eight coal-shale joints by letting the two segments of the fitting curve pass through the peak point of each curve. Findings. The two-segment model well describes the shear resistance variation of the coal-shale joints during the shear process, and there exist good relationships between the fitting parameters and the shear testing parameters. The initial slope of the softening part of the shear resistance – shear displacement curve can help to predict whether the coal pillar will burst drastically when it fails. Moreover, the normal displacement was very small in the pre-peak range which indicates that the complete detachment of original coal-shale joint surfaces has not occurred before the peak. Originality. Direct shear tests were conducted on original coal-shale specimens for the first time, and a two-segment model is developed to describe their shear resistance-shear displacement curves. The initial slope of the softening part of the shear resistance – shear displacement curve is proposed to predict the burst tendency of coal pillar. Different from unbonded rock joints, the detachment of the original coal-shale joint occurs just after the peak. Practical implications. The conclusions may have some help to understand the shear resistance mechanism of original coal-shale joint and to provide some new ideas of maintaining coal pillar stability.Мета. Експериментальне дослідження та теоретичне моделювання опору зсуву початкового шару вуглистого сланцю. Методика. Розроблено модель для опису кривих опору зсуву й зсувного зміщення, отриманих у результаті випробувань на прямий зсув восьми шарів вуглистого сланцю. Модель включає два сегменти апроксимуючої кривої, що проходять через вищі точки описуваних кривих. Результати. Запропонована модель достовірно описує зміну опору на зсув шарів вуглистого сланцю в про-процесі зсуву, при цьому визначено наявність тісного зв’язку між параметрами апроксимації та параметрами випробування на зсув. За початковим нахилом кривої в частині ослаблення опору зсуву й зсувного зміщення можна передбачити, чи відбудеться значне руйнування цілика вугілля при його обваленні. Нормальне зміщення є незначним у передпіковому діапазоні, що свідчить про те, що в цей час не відбувається повного відриву поверхонь шару вуглистого сланцю. Наукова новизна. Випробування на прямий зсув проводилися вперше на зразках початкового вуглистого сланцю. Двохсегментна модель була розроблена спеціально для опису кривих опору зсуву та зсувного зміщення досліджуваних шарів. За початковим нахилом кривої в частині ослаблення опору зсуву й зсувного зміщення можна передбачити характер руйнування цілика. На відміну від незв’язаних шарів породи, відділення початкового шару вуглистого сланцю відбувається після пікових значень досліджуваних кривих. Практична значимість. Висновки можуть допомогти зрозуміти механізм опору зсуву в первісному шарі вуглистого сланцю й окреслити нові підходи до збереження стабільності вугільного цілика.Цель. Экспериментальное исследование и теоретическое моделирование сопротивления сдвигу первоначального слоя углистого сланца. Методика. Разработана модель для описания кривых сопротивления сдвигу и сдвигового смещения, полученных в результате испытаний на прямой сдвиг восьми слоев углистого сланца. Модель включает два сегмента аппроксимирующей кривой которые проходят через высшие точки описываемых кривых. Результаты. Предлагаемая модель достоверно описывает изменение сопротивления на сдвиг слоев углистого сланца в процессе сдвига, при этом определено наличие тесной связи между параметрами аппроксимации и параметрами испытания на сдвиг. По начальному наклону кривой в части ослабления сопротивления сдвигу и сдвигового смещения можно предсказать, произойдет ли значительное разрушение целика угля при его обрушении. Нормальное смещение незначительно в предпиковом диапазоне, что свидетельствует о том, что в это время не происходит полного отрыва поверхностей слоя углистого сланца. Научная новизна. Испытания на прямой сдвиг проводились впервые на образцах первоначального углистого сланца. Двухсегментная модель была разработана специально для описания кривых сопротивления сдвигу и сдвигового смещения исследуемых слоев. По начальному наклону кривой в части ослабления сопротивления сдвигу и сдвигового смещения можно предсказать характер разрушения целика. В отличие от несвязанных слоев породы, отделение первоначального слоя углистого сланца происходит после пиковых значений исследуемых кривых. Практическая значимость. Выводы могут помочь понять механизм сопротивления сдвигу в первоначальном слое углистого сланца и обозначить новые подходы к сохранению стабильности угольного целика.The authors gratefully acknowledge funding by China National Natural Science Foundation (51109076) and the key scientific and technological project of Henan Province (152102210316)