• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.10 no.2
• /
• pp.41-47
• /
• 2006

The Renewal process and the Non-homogeneous Poisson process (NHPP) process are probably the most popular models for describing the failure pattern of repairable systems. But both these models are based on too restrictive assumptions on the effect of the repair action. For these reasons, several authors have recently proposed point process models which incorporate both renewal type behavior and time trend. One of these models is the Modulated Power Law Process (MPLP). The Modulated Power Law Process is a suitable model for describing the failure pattern of repairable systems when both renewal-type behavior and time trend are present. In this paper we propose Bayes estimation of the next failure time after the system has experienced some failures, that is, Mean Time Between Failure for the MPLP model. Numerical examples illustrate the estimation procedure.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2007.05a
• /
• pp.191-194
• /
• 2007

In hot embossing lithography which has shown to be a good method to fabricate polymeric patterns for IT and bio components, it is very important to determine the proper process conditions of pressure, temperature, and time. It is also a key factor for predicting the optical properties of final product to calculate residual stress distribution after the embossing process. Therefore, to design the optimum process with right conditions, the ability to predict viscoelastic behavior of polymer during and after the hot embossing process is required. The objective of the present investigation is to establish simulation technique based on constitutive modeling of polymer with experiments. To analyze deformation behavior of viscoelastic polymer, the large strain material properties were obtained from quasi-static compression tests at different strain rates and temperatures and also stress relaxation tests were executed. With this viscoelastic material model, finite element simulation of hot embossing was executed and stress distribution is obtained. Proper process pressure is very important to predict the defect and incomplete filling.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.17 no.2
• /
• pp.219-231
• /
• 1993

According to the literatures of marketing, psychology, and other related areas, the situational influences on consumers' decision-making process have been significant, thus increased explanatory power of consume behavior when introduced in a research as one of the independent variables. Considering the characteristics of clothing as a consumer goods, situational influences on clothing purchase behavior were expected to be significant. As the theoretical backgrounds of situational influences on clothing purchase behavior, this study was to propose the definition of sitution in Clothing & Textiles department, and to suggest the types of situational variables affecting clothing purchase process in consideration of the results of consumer behavior research and the research related to clothing. The results of this study suggested that the definition of situation, subjective situation or objective situation, should be adjusted to the purpose of research, and that the types of situations affecting clothing purchase process might be defined into three types; wearing situation, communication situation, and purchasing situation. It was also suggested that the empirical studies would be necessary to verify the results, and the conceptual framework for the types of situations and the personality characteristics related to the clothing purchase situation should be identified.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.24 no.6
• /
• pp.907-917
• /
• 2000

Although interest in the potential and actual usage of the Internet as a transaction medium is increasing, the market for fashion merchandise on the Internet in Korea has yet to take off. As the Internet environment is expected to bring about a transformation of conventional consumer buying behavior, the purpose of this exploratory research is to investigate the buying behavior of fashion products on the Internet to identify relevant concepts and generate hypotheses for further empirical research. The research methods selected for the study were observation and in-depth interview. Twelve subjects who had purchased fashion products on the Internet were selected and interviewed. Those who could not participate in face-to-face in-depth interviews because of the geographic locations were interviewed on-line. The results are as follows: First, subjects went through the stages of shopping motivation stage, site choice behavior stage, in-site behavior stage, and postpurchase behavior stage. Second, a model was extracted for each shopping stage, and a final model was completed based on comparisons with the participants processes. The information content of each phase was discussed. Finally, each participant was classified using their purchasing process, revealing six possible mixed usage patterns of the Internet marketing system and the traditional marketing system.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.44 no.1
• /
• pp.10-19
• /
• 2008

This paper focuses on the mackerel's visual ability and swimming capability, and aims to describe the behavior in capture and escape process by trawl. The visual sensory systems and reaction behavior based locomotory capability were analyzed and simulated. The ability of fish to see an object depends on the light intensity and the contrast and size of the object. Swimming endurance of the fish is dependent on the swimming speed and the size of the fish. Swimming speeds of the fish are simulated 3 types of the burst speed, the prolonged speed and the sustained speed according to the time they can maintain to swim. The herding and avoiding is typical reaction of the fish to the stimuli of trawl gear in the capture process. These basic behavior patterns of the virtual mackerel to the gear are simulated. This simulation will be helpful to understand the fishing processes and make high selectivity of fishing.

• Fisheries and Aquatic Sciences
• /
• v.7 no.3
• /
• pp.163-170
• /
• 2004

A fishing simulator for towed fishing gear was investigated in order to mimic the fish behavior in capture process and investigate fishing selectivity. A fish behavior model using a psycho-hydraulic wheel activated by stimuli is established to introduce Lorenz chaos equations and a neural network system and to generate the components of realistic fish capture processes. The fish positions within the specified gear geometry are calculated from normalized intensities of the stimuli of the fishing gear components or neighboring fish and then these are related to the sensitivities and the abilities of the fish. This study is applied to four different towed gears i.e. a bottom trawl, a midwater trawl, a two-boat seine, and an anchovy boat seine and for 17 fish species as mainly caught. The Alpha cluster computer system and Fortran MPI (Message-Passing Interface) parallel programming were used for rapid calculation and mass data processing in this chaotic behavior model. The results of the simulation can be represented as animation of fish movements in relation to fishing gear using Open-GL and C graphic programming and catch data as well as selectivity analysis. The results of this simulator mimicked closely the field studies of the same gears and can therefore be used in further study of fishing gear design, predicting selectivity and indoor training systems.

• Transactions of Materials Processing
• /
• v.6 no.2
• /
• pp.161-175
• /
• 1997

The effects of various process paramenters on the detailed aspects of the thermo-mechanical behavior of work roll and on the roll life are investigated via a series of process simulation, using a mathematical model presented previously. The process conditions are discussed that are favorable or optimal in terms of reducing roll wear in the front finishing stands.

• Composites Research
• /
• v.33 no.5
• /
• pp.302-308
• /
• 2020

We measured the thermal conductivity of composite materials manufactured by the autoclave and vacuum bag only processes and predicted the cure behavior of the external and internal of composite parts with a cure kinetics model. The temperature difference between the external and internal depends on the processes because of the change of thermal conductivity. In the autoclave process, the temperature and cure behavior of the internal were similar to those of the external because of the high thermal conductivity. However, the temperature of the internal of the vacuum bag only process was different from that of the external. The difference can influence the part quality and evacuation of air. Compression tests were performed to find the mechanical property using 0° unidirectional specimens. The composite of the vacuum bag only process was found to have a lower compressive strength than that of the autoclave process.

• 한국산학경영학회:학술대회논문집
• /
• 2005.11a
• /
• pp.1-9
• /
• 2005

Job search research has been criticized for failing to study the dynamics and change of the job search process. A lot of previous researches have used cross-sectional designs and treated job search as a static process. As a result, job search research has failed to examine how job seekers' behaviors change during the course of their search. This paper examined changes In job search behaviors(preparatory and active job search behavior, and job search intensity) and the effects of individual difference variables(self-esteem, self-efficacy, extroversion, agreeableness, conscientiousness, openness) on job search behaviors. Data were gathered from 404 university students who had not found employment at the time of beginning of second semester The results of t-test pairs indicated that job seeking students increased their preparatory job search behavior and active job search behavior, but didn't job search intensity. The results of multiple regression showed that self-efficacy had strong relationship with preparatory and active job search behavior, and job search intensity, but self-esteem had not any relationship with them. Among big-5 personality, extroversion had relationship with active job search behavior and job search intensity, and agreeableness only with job search intensity.

• Korean Journal of Child Studies
• /
• v.19 no.2
• /
• pp.49-64
• /
• 1998

The theoretical process model was used to study problem behavior of children growing up at-risk. A sample of 339 children living in at-risk families were selected from among 2, 134 children in grades 4, 5, and 6 of five elementary schools in Seoul. The instruments were five risk factor scales and four protective factor scales. The Child Behavior Checklist was also used. The results of the hypothetical model of children at-risk showed that the factor of socioeconomic status led to positive child rearing attitudes in mothers, which is turn influenced children's problem behavior indirectly. In contrast, stressful life events and mother's depression influenced children's problem behavior directly. However, negative family functioning, marital discord and father's depression did not influence mother's child rearing attitudes or children's problem behavior. Mother's child rearing attitudes directly influenced children's social competence and academic achievement and indirectly influenced their problem behavior. Academic achievement did not influence problem behavior directly, but social competence influenced it directly. Mother's child rearing attitude was the most significant factor affecting children's adaptation.