• Proceedings of the Korean Operations and Management Science Society Conference
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• 2008.10a
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• pp.324-328
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• 2008

금융산업에서 고객의 이탈비율은 기대수익에 영향을 미친다는 점에서 예측이 필요한 부분이며 최근 들어 정확한 예측을 통한 비용관리가 이루어지면서 고객 이탈을 예측하는 것이 중요한 문제로 떠오르고 있다. 그러나 보험 고객 데이터가 대용량이고 불균형한 출력 값을 갖는 특성으로 인해 기존의 방법으로 예측 모델을 만드는 것이 적합하지 않다. 본 연구에서는 대용량 데이터를 처리하는 데 효과적으로 알려져 있는 Trust-region Newton method를 적용한 로지스틱 회귀분석을 통해 이탈고객을 예측하는 것을 주된 연구로 하며, 불균형한 데이터에서의 예측정확도를 높이기 위해 Oversampling, Clustering, Boosting 등을 이용하여 고객 데이터에 적합한 이탈 고객 예측 모형을 제시하고자 한다.

• Journal of Information Technology Services
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• v.10 no.2
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• pp.21-39
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• 2011

After ten years from the introduction of CRM systems, many companies reevaluate CRM from the perspective of customers. This paper classifies CRM activities at the contact points with customers and investigates the effect of CRM activities on perceived benefits and the effect of perceived benefits on behavioral intention in the Korean cosmetic industry. The result showed that contact management and complaint handling affected social benefits and that customers perceived confidence benefits from contact management, complaint handling, and churn management. Special treatment benefits were affected by all CRM activities including compensation management. Finally, all kinds of benefits had effects on behavioral intention such as recommendation intention and repurchase intention.

• Proceedings of the Korean Society of Computer Information Conference
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• 2013.07a
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• pp.109-110
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• 2013

국내 이동통신 서비스 시장 사업자들은 신규고객 유치에 집중하기 보다는 기존고객 유지에 더 관심을 가지고 있다. 이러한 배경에는 새로운 신규고객의 창출에 소요되는 비용이 기존고객을 유지하는 비용이 적게 들기 때문이다. 따라서 고객이탈을 발생시키는 요인이 무엇인지를 본 연구에서 알아보고자 한다.

• Journal of Environmental Science International
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• v.6 no.1
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• pp.25-31
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• 1997

The variations of gas hold-up, overall volumetric oxygen mass transfer coefficients and liquid circulation velocity in an internal loop reactor were investigated to manifest scale-up effect. The relationship between superficial gas velocity and gas hold-up were found as Ugr = 0.045 $\varepsilon$r in the pilot-scale and Ugr = 0.056 $\varepsilon$r in the bench-scale reactor. The overall volumetric oxygen mass tractsfer coefficient, KLa was slightly increased in the pilot-scale than in the bench-scale reactor. Flow regime was changed from the bubble flow to the churn-turbulent flow when the superficial gas velocity reached to 3.5 - 4 cm/sec in the pilot-scale.

• The Journal of Information Systems
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• v.18 no.3
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• pp.375-399
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• 2009

In this study, we propose a integrated model of logistic regression, artificial neural networks, support vector machines(SVM), with case-based reasoning(CBR). To predict respondents in the direct marketing is the binary classification problem as like bankruptcy prediction, IDS, churn management and so on. To solve the binary problems, we employed logistic regression, artificial neural networks, SVM. and CBR. CBR is a problem-solving technique and shows significant promise for improving the effectiveness of complex and unstructured decision making, and we can obtain excellent results through CBR in this study. Experimental results show that the classification accuracy of integration model using CBR is superior to logistic regression, artificial neural networks and SVM. When we apply the customer response model to predict respondents in the direct marketing, we have to consider from the view point of profit/cost about the misclassification.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.280-284
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• 2003

효과적인 CRM(고객관계관리)을 위해서 고객의 가치를 파악하는 것은 매우 중요하다. 모든 고객이 같은 가치를 제공하지 않기 때문에 차별적인 서비스를 통해 장기적인 관점에서 기업의 수익을 최대화한다는 것이 CRM의 기본전제가 되기 때문이다. 기존의 고객가치를 측정하는 것은 LTV(고객생애가치)를 중심으로 연구되어 왔다. 그러나 이러한 LTV는 환경의 변동성, 고객의 변동성 등 많은 불확실성을 안고 측정될 수밖에 없고 단순히 과거 기업에게 제공된 과거 수익의 추이를 고려하기 때문에 실제 세분화 시 간과하게 되는 점이 많다. 따라서 본 논문에서는 단기적인 활용관점에서 고객의 이탈률(Churn Rate)을 고려하여 고객의 가치를 현재가치, 잠재가치로 나누어 측정하고 이를 통해 고객 세분화의 방안을 제시해 본다.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.461-468
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• 2005

In this paper, mixed mode magneto-rheological (MR) damper, which is applicable for vibration control of a small scale multi-story structure, is devised. First, the schematic configurations of the shear, flow, and mixed mode MR dampers are described with design constraints and then the analytical models to predict the field-dependent damping forces are derived for each type. Second, an appropriate size of the mixed mode MR damper is manufactured and its field-dependent damping characteristics are evaluated in time domain. Finally, the performance of the manufactured MR damper which is semi-actively applied to a small scale building excited by earthquake load, is numerically evaluated.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.527-532
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• 2010

In this study, vertical and horizontal accelerometers were installed at the both side of car body and tachometer was installed on the bogie, for the purpose of stability analysis of Korail Airport Express Train during driving. By applying the developed algorithm, the peak-to-peaks of horizontal and vertical acceleration which were matched with location by tachometer were found and compared with the threshold values. The threshold values per velocities which were presented in the "Metro Train Performance Criteria" were applied here. The validity of the developed algorithm was shown by comparing the site investigation and the measured values at frost heave locations.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.2095-2106
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• 2010

In this study, to grasp the stability of train and to identify the track irregularity, the algorithm was proposed. As the track deformation occur due to running train, the dynamic characteristics of train show non-linearity. The representative transfer functions of wheel to car response were calculated from the frequency response functions which were estimated from measured triaxial accelerations. The measured acceleration responses were compared with the estimated responses from filtered acceleration outputs. This result could show the non-linearity of train system at the location of track deformed. The proposed algorithm was verified by matching with the site investigation.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.241-246
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• 1996

An analytical model to calculate rate of vapor generation due to heterogeneous wall nucleation in flashing flow is developed. In the present model, an important parameter of the vapor generation term, i.e. nucleation site density is calculated by integrating its probability distribution function with respect to active cavity radius. The limits of integration are minimum and maximum active cavity radii, and these are formulated using an active cavity model for nucleate boiling. This formulation, therefore. can statistically account for the effect of surface specific thermo-physical and geometric conditions on the vapor generation rate and flashing inception. For verifying the adequacy of the present model, steady state two-fluid and the bubble transport equations are solved with applicable constitutive equations. The applicable region of the bubble transport equation is also extended to churn-turbulent flow regime to predict interfacial area concentration at high void fraction. Predicted results in terms of axial pressure and void fraction profiles along the channels are compared with experimental data of Super Moby Dick and BNL Reasonable agreements have been achieved and this shows the applicability of the present model to flashing flow analysis.