• Asia pacific journal of information systems
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• 제26권1호
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• pp.66-79
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• 2016

The availability of detailed data on customers' online behaviors and advances in big data analysis techniques enable us to predict consumer behaviors. In the past, researchers have built purchase prediction models by analyzing clickstream data; however, these clickstream-based prediction models have had several limitations. In this study, we propose a new method for purchase prediction that combines information theory with machine learning techniques. Clickstreams from 5,000 panel members and data on their purchases of electronics, fashion, and cosmetics products were analyzed. Clickstreams were summarized using the 'entropy' concept from information theory, while 'random forests' method was applied to build prediction models. The results show that prediction accuracy of this new method ranges from 0.56 to 0.83, which is a significant improvement over values for clickstream-based prediction models presented in the past. The results indicate further that consumers' information search behaviors differ significantly across product categories.

• 한국생산제조학회지
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• 제20권1호
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• pp.74-80
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• 2011

In this study, a variety of welding experiments were carried out to optimize root-pass welding process using GMA process. Based on the experimental results, optimal welding conditions were selected after analyzing correlation between welding parameters and back-bead geometry. Then, effectiveness of empirical models developed was compared and analyzed, and optimized empirical models were finally developed for predicting back-bead by analyzing the main effect of each factor which affects back-bead geometry and their influence on interaction. Also, functions proper for expressing the surface of back-bead were selected using diverse quadratic functions, and back-bead geometry was visualized using empirical models developed and quadratic functions.

• International Journal of Contents
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• 제8권3호
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• pp.71-78
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• 2012

The emergence of the Internet has provided a new outlet for consumers who experience service failure from products and services, augmenting the traditional options of entry, voice and action. Consumers' negative word of mouth through online (word-of-mouse or eWOM) far exceeds traditional word of mouth (WOM) in respect of its potential effectiveness, speed and spread. This paper tries to figure out the service failure themes in the health care industry by analyzing online word-of-mouse using the critical incidents technique (CIT). Complaint themes in the area of healthcare are identified and analyzed. The results identify that major complaint theme differed according to the site type. Also, the findings indicate that delivery and customer services are critical issues when consumer makes negative WOM.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.43-46
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• 1997

Reliability engineering is regarded as the major and important roll for all industry. And advanced manufacturing systems with high sped and intelligent have been developing for betterment of machining ability. In this study, we have systemized evaluation of reliability for machinery system. We proposed the reliability assessment and designed and manufactured reliability test-bed to evaluate reliability. In addition we acquired reliability data using test-bed system and made database to handle reliability data. And also we not only use reliability data by analyzing reliability, but also apply design review method using analyzing critical units of machinery system. Form this study, we will expect to guide and increase the reliability engineering in developing and processing phase of high quality product.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.336-340
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• 1997

For optimal design of micro stage, we were measured to displacement of piezo-electric transducer that was based on voltage value. And then researchers were analyzed to microstage through FEM with displacement data including voltage value of piezo-electric transducer. For verification of analyzing results, we were gauged on displacement by using Laser-interferometer. And researchers were confirmed to propriety of micro stage design with FEM, were obtained error rate that are 3.5% between measurement results and analyzing results.

• Asia pacific journal of information systems
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• 제12권1호
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• pp.17-44
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• 2002

This study is to propose a framework for analyzing the role of information systems in organizations, and to make an overture it's applicability for empirical studies to be performed in the future. To accomplish these purposes, this study identified major dimensions which can explain the introduction of various applications based on the interviews with IS staffs of a domestic car manufacturing firm, and reviewed the past researches which discussed the roles of information systems regarding those dimensions. From this mixed approach, this study defined the research dimensions to analyze the role of information systems, which are consisted of the purpose of information processing and the scope of information processing. And then, this study performed the longitudinal case study to analyze the role of information systems in organizational growth based on the framework.

• Journal of Advanced Marine Engineering and Technology
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• 제30권2호
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• pp.247-252
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• 2006

Almost ship monitoring systems are event driven alarm system which warn only when the measurement value is over or under set point. These kinds of system cannot warn until signal is growing to abnormal state that the signal is over or under the set point. therefore cannot play a role for preventive maintenance system. This paper proposes fault diagnosis method which is able to diagnose and forecast the fault from present operating condition by analyzing monitored signals with present ship monitoring system without any additional sensors. By analyzing the data with high correlation coefficient(CC), correlation level of interactive data can be defined. Knowledge base of abnormal detection can be built by referring level of CC(Fault Detection CC. FDCC) to detect abnormal data among monitored data from monitoring system and knowledge base of diagnosis built by referring CC among interactive data for related machine each other to diagnose fault part.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.377-382
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• 2001

A suboptimal control law in turbulent pipe flow is derived and tested. Two sensing variables ${\partial}p/{\partial}{\theta}\;|_w\;and\;{\partial}{\upsilon}_{\theta}/{\partial}r\;|_w$ are applied with two actuations ${\phi}_{\theta}$ and ${\phi}_r$. To test the suboptimal control law, direct numerical simulations of turbulent pipe flow at $Re_r=150$ are performed. When the control law is applied, a $13{\sim}23%$ drag reduction is achieved. The most effective drag reduction is made at the pair of ${\partial}{\upsilon}_{\theta}/{\partial}r\;|_w$ and ${\theta}_r$. An impenetrable virtual wall concept is useful for analyzing the near-wall suction and blowing. The virtual wall concept is useful for analyzing the near-wall behavior of the controlled flow. Comparison of the present suboptimal control with that of turbulent channel flow reveals that the curvature effect is insignificant.

• 한국정밀공학회지
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• 제13권9호
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• pp.31-37
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• 1996

This Paper is concerned with effective signal identification method for tool breakage and micro chipping using discrete wavelet transform of feed motor current in milling operations. The wavelet transform uses an analyzing waveletfunction which is localized in both frequency and time domain to detect subtle time localized changes in input signals. The changing pattern of wavelet coefficient is continuously compared to detect tool breakage and micro chipping over one spindle revolution. The results indicate that the wavelet transform can identify tool failure with much greater sensi- tivity than the time domain monitoring and frequency domain monitoring such as FFT. Experimental results are presented to support the proposed scheme.

• 대한전자공학회논문지
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• 제25권10호
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• pp.1166-1172
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• 1988

본 논문의 Taylor 다항식에 의해 선형 시변 시스템을 해석하는 한 효과적인 방법을 제안한다. Sparis와 Mouroutsos에 의한 방법은 구해야 할 상태 벡타가 닫혀진 형태(closed form)로 구해지지 않고 또한 사용하는 항이 증가할 때 큰 차원의 선형 대수 방정식을 출어야 하는 문제점을 가지고 있다. 반면에 본 논문에서 제안된 방법은 상태 벡타가 닫혀진 형태로 구해지며 선형 대수 방정식을 풀 필요가 없다.