• 지능정보연구
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• 제14권4호
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• pp.89-101
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• 2008

제조 분야에서 품질관리를 위해 가장 많이 사용되는 도구는 관리도이다. 하지만 휴대용 카메라 모듈과 같은 소형 전자부품의 제조 라인은 자동화되어 여러 개의 공정이 유기적으로 연결되어 있는 경우 관리도의 적용이 쉽지 않다. 이러한 문제점을 해결하기 위해 공정의 흐름을 파악할 수 있는 모니터링체계와 수율 예측 및 주요공정 변수 파악 등의 주요 공정 파라메터 추출 체계로 구성된 데이터마이닝 기반 품질관리시스템을 구축하고자 한다. 데이터마이닝을 위해 품질관리시스템은 의사결정나무, 신경망, 패턴분석 등의 모듈을 사용한다. 제안된 시스템을 통해 제조 공정은 안정적인 품질의 유지 및 공정 이상 유무의 신속한 파악, 수율 예측 등 품질관리를 위한 유용한 정보를 제공하고 공정의 신뢰성을 높이는데 기여할 수 있을 것이다.

• Geomechanics and Engineering
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• 제29권5호
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• pp.509-522
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• 2022

Tail-grouting is an effective measure in shield engineering for filling the gap at the shield tail to reduce ground deformation. However, the gap-filling ratio affects the value of the gap parameters, leading to different surface settlements. It is impossible to adjust the fill ratio indiscriminately to study its effect, because the allowable adjustment range of the grouting quantity is limited to ensure construction site safety. In this study, taking the shield tunnel section between Chaoyanggang Station and Shilihe Station of Beijing Metro Line 17 as an example, the correlation between the tail-grouting parameter and the surface settlement is investigated and the optimal grouting quantity is evaluated. This site is suitable for conducting field tests to reduce the tail-grouting quantity of shield tunneling over a large range. In addition, the shield tunneling under different grouting parameters was simulated. Furthermore, we analyzed the evolution law of the surface settlement under different grouting parameters and obtained the difference in the settlement parameters for each construction stage. The results obtained indicate that the characteristics of the grout affect the development of the surface settlement. Therefore, reducing the setting time or increasing the initial strength of the grout could effectively suppress the development of surface subsidence. As the fill ratio decreases, the loose zone of the soil above the tunnel expands, and the soil deformation is easily transmitted to the surface. Meanwhile, owing to insufficient grout support, the lateral pressure on the tunnel segments is significantly reduced, and the segment moves considerably after being removed from the shield tail.

• Geomechanics and Engineering
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• 제15권2호
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• pp.769-774
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• 2018

The growth of cities requires the construction of new tunnels close to the existing ones. Prediction and control of ground movement around the tunnel are important especially in urban area. The ground respond due to EPB (Earth Pressure Balance) pressure are investigated using the finite element method by ABAQUS in intersection of the triplet tunnels (Line 2, 3 and 4) of Mashhad Urban Railway in Iran. Special attention is paid to the effect of EPB pressure on the tunnel face displacement. The results of the analysis show that in EPB tunneling, surface settlement and face displacement is related to EPB pressure. Moreover, it is found that tunnel construction sequence is a great effect in face displacement value. For this study, this value in Line 4 where is excavated after line 3, is smaller than that line. In addition, the trend of the displacement curves are changed with the depth for all lines where is located in above and below, close to and above the centerline tunnel face for Line 2, 3 and 4, respectively. It is concluded that: (i) the surface settlement decreases with increasing EPB pressure on the tunnel face; (ii) at a constant EPB pressure, the tunnel face displacement values increase with depth. In addition, this is depended on the tunneling sequence; (iii) the trend of the displacement curves change with the depth.

• 전기학회논문지
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• 제57권11호
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• pp.1910-1915
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• 2008

The load analysis for the distribution system and facilities has relied on measurement equipment. Moreover, load monitoring incurs huge costs in terms of installation and maintenance. This paper presents a new model to analyze wherein facilities load under a feeder every 15 minutes using meter reading data that can be obtained from a power consumer every 15 minute or a month even without setting up any measuring equipment. After the data warehouse is constructed by interfacing the legacy system required for the load calculation, the relationship between the distribution system and the power consumer is established. Once the load pattern is forecasted by applying clustering and classification algorithm of temporal data mining techniques for the power customer who is not involved in Automatic Meter Reading(AMR), a single-line diagram per feeder is created, and power flow calculation is executed. The calculation result is analyzed using various temporal and spatial analysis methods such as Internet Geographic Information System(GIS), single-line diagram, and Online Analytical Processing (OLAP).

• Journal of Information Processing Systems
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• 제1권1호
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• pp.9-13
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• 2005

Computer security has become a critical issue with the rapid development of business and other transaction systems over the Internet. The application of artificial intelligence, machine learning and data mining techniques to intrusion detection systems has been increasing recently. But most research is focused on improving the classification performance of a classifier. Selecting important features from input data leads to simplification of the problem, and faster and more accurate detection rates. Thus selecting important features is an important issue in intrusion detection. Another issue in intrusion detection is that most of the intrusion detection systems are performed by off-line and it is not a suitable method for a real-time intrusion detection system. In this paper, we develop the real-time intrusion detection system, which combines an on-line feature extraction method with the Least Squares Support Vector Machine classifier. Applying the proposed system to KDD CUP 99 data, experimental results show that it has a remarkable feature extraction and classification performance compared to existing off-line intrusion detection systems.

• 지구물리와물리탐사
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• 제5권1호
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• pp.23-32
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• 2002

비접지식 전기비저항 탐사는 땅에 접지전극을 설치하기 어려운 곳에서 전기비저항 탐사를 수행할 수 있는 방법으로 국내에서도 관심이 높아지고 있는 방법이다. 이 방법의 기본원리는 땅과 송수신 안테나의 용량결합(capacitive coupling)에 의하여 지하로 전류를 주입하고 이에 의한 전위차를 측정하여 자료를 획득하는 것이다. 본 연구에서는 쌍극자 및 단극 형태의 송수신 안테나를 일렬로 배치하는 방사 배열(radial array)에 대한 기하학적 상수를 유도하였다. 또한, 기존의 접지식 전기비저항 해석 알고리듬을 이용하여 비접지식 전기비저항 자료를 해석하기 위한 자료 전처리 및 변환 과정을 제시하였다. 즉, 획득된 탐사 자료를 기하학적 상수를 이용하여 일단 겉보기 비저항으로 변환한 후 쌍극자 배열이나 변형된 쌍극자 배열 자료로 보간 혹은 재샘플링함으로써 기존의 접지식 전기비저항 역산 알고리듬을 이용하여 해석하였는데, 동일 측선에서 수행한 접지식 및 비접지식 탐사 자료와 비교하여 그 타당성을 검증하였다. 비접지식 전기비저항 탐사법은 전류를 많이 주입할 수 없는 기기 상의 단점을 갖고 있음을 알 수 있었는데, 특히 전기비저항이 낮은 곳이나, 전기적 잡음이 심한 곳, 그리고 송수신 안테나의 접촉이 좋지 않은 지역에 적용함에 있어 세심한 주의가 요구된다. 그러나, 송수신 안테나를 일렬로 배열하여 견인함으로써 연속적으로 탐사 자료를 획득할 수 있고 전극 설치가 불가능한 지역에서 전기비저항 탐사를 수행할 수 있으므로, 신속하게 지하 천부에 대한 전기비저항 분포를 알고자 할 때 유용하게 쓰일 것으로 생각된다.

• 한국문헌정보학회지
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• 제47권4호
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• pp.315-334
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• 2013

이 연구에서는 토픽 모델링 기법을 이용하여 신문 기사를 대상으로 주제 기반의 오피니언 마이닝을 수행하였다. 언론 매체가 가지는 정파성을 일종의 오피니언으로 간주하여 대선이라는 거대 이슈에 대한 각 매체들의 입장을 분석하였다. 먼저 대량의 신문 기사에서 주제를 추출한 후 매체별 주제 구성의 차이를 살펴보았다. 그리고 주제별 네트워크 분석을 통해 주제의 구조와 내용을 분석하였다. 마지막으로 시계열 분석을 통해서 시기별 주제 분포의 차이를 매체별로 살펴보았다. 그 결과 모든 분석에서 진보매체와 보수매체 모두 자신들의 이데올로기를 따라 기사를 보도하는 경향성이 확인되었다. 이를 통해 주제 기반 오피니언 마이닝이 타당성 있는 의견 분석의 기능을 수행할 수 있음을 확인할 수 있었다.

• 경영과학
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• 제21권3호
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• pp.85-99
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• 2004

The retention of customer is an increasingly pressing issue in today's competitive environment. The proposes of this paper is a personalized defection detection and the procedure of prevention based on economic analysis of customer defection possibility, and behaviour state transition cost. This procedure is based on the observation that potential defectors have a tendency to take a couple of months or weeks to gradually change their behaviour before their eventual withdrawal. In this procedure, the SOM(Self-Organizing Map) is used to determine the possible states of customer behaviour from past behaviour data, and to prevent the defection of potential defectors, the proposed procedure recommends the desirable behaviour state for the next period based on the analysis of transition cost. and likelihood of defection. The case study has been conducted for a Korean on-line game provider to evaluate of this procedure.

• Geomechanics and Engineering
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• 제29권4호
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• pp.471-486
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• 2022

The effect of segmental joints is one of main importance for the segmental lining design when tunnels are excavated by a mechanized process. In this paper, segmental tunnel linings are analyzed by two numerical methods, namely the Beam-Spring Method (BSM) and the Solid-Interface Method (SIM). For this purpose, the Tehran Subway Line 6 Tunnel is considered to be the reference case. Comprehensive 2D numerical simulations are performed considering the soil's calibrated plastic hardening model (PH). Also, an advanced 3D numerical model was used to obtain the stress relaxation value. The SIM numerical model is conducted to calculate the average rotational stiffness of the longitudinal joints considering the joints bending moment distribution and joints openings. Then, based on the BSM, a sensitivity analysis was performed to investigate the influence of the ground rigidity, depth to diameter ratios, slippage between the segment and ground, segment thickness, number of segments and pattern of joints. The findings indicate that when the longitudinal joints are flexible, the soil-segment interaction effect is significant. The joint rotational stiffness effect becomes remarkable with increasing the segment thickness, segment number, and tunnel depth. The pattern of longitudinal joints, in addition to the joint stiffness ratio and number of segments, also depends on the placement of longitudinal joints of the key segment in the tunnel crown (similar to patterns B and B').

• Asia pacific journal of information systems
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• 제15권3호
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• pp.209-221
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• 2005

One of the most fundamental problems in business is to evaluate the value of each product. The difficulty is that the profit of one product not only comes from its own sales, but also its influence on the sales of other products, i.e., the "cross-selling effect". This study integrates a measure for cross selling and an algorithm for profit estimation. Sales transaction data and post sales survey data from on-line and off-line shopping mall is used to show the effectiveness of the method against other heuristic for profit estimation based on product-specific profitability. We show that with the use of the new method we are able to identify the cross-selling potential of each product and use the information for better product selection.