• Journal of the Korean Society for Railway
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• v.13 no.1
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• pp.58-64
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• 2010

As a modem urban train is getting complex in terms of high-technology in its systems and components, the failure management should be performed with scientific and systematic technique. FMEA is a technique to analyze the failure trends of component parts and influences to the higher level system in order to discover the design incompleteness and potential defects, which is for improving reliability. Especially, FMECA (Failure Mode Effects, and Criticality Analysis) is used in case that the criticality that has an immense influence to the system is important. In case of urban train, in its design and manufacturing steps, FMEA is frequently used as an analysis technique to meet the safety objectives and eliminate potential hazards/failures since the concepts of reliability of train is introduced these days. Though, FMEA technique in the maintenances steps lacks in its investigation and applications yet. FMEA is also not applied to the trains operated by Seoul metro in the design and manufacture steps excepts the newest trains. In this paper, through analyzing the failures/maintenance data of the belt-type door systems used in trains operated in Seoul metro Line 1, which is accumulated in RIMS (Rolling-stock Information Maintenance System), FMEA procedures to the belt-type door engines are proposed. Especially, an effort is made, to approach the detailed FMECA procedures to the door magnet valve and switch and door engine devices which vastly influences the customer safety and satisfaction.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.12
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• pp.209-218
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• 2012

Recently, the Field Programmable Stateful Logic Array (FPSLA) was proposed as one of the most promising system integration technologies which will extend the life of the Moore's law. This work is the first proposal of the FPSLA design automation flow, and the approaches to logic synthesis, synchronization, physical mapping, and automatic placement of the FPSLA designs. The synchronization at each gate for pipelining determines the x-coordinates of cells, and reduces the placement to 1-dimensional problems. The objective function and its gradients for the non-linear optimization of the net length and placement density have been remodeled for the reduced global placement problem. Also, a recursive algorithm has been proposed to legalize the placement by relaxing the density overflow of bipartite bin groups in a top-down hierarchical fashion. The proposed model and algorithm are implemented, and validated by applying them to the ACM/SIGDA benchmark designs. The output state of a gate in an FPSLA needs to be duplicated so that each fanout gate can be connected to a dedicated copy. This property has been taken into account by merging the duplicated nets into a hyperedge, and then, splitting the hyperedge into edges as the optimization progresses. This yields additional 18.4% of the cell count reduction in the most dense logic stage. The practicality of the FPSLA can be further enhanced primarily by incorporating into the logic synthesis the constraint to avoid the concentrated fains of gates on some logic stages. In addition, an efficient algorithm needs to be devised for the routing problem which is based on a complicated graph. The graph models the nanowire crossbar which is trimmed to be embedded into the FPSLA fabric, and therefore, asymmetric. These CAD tools can be used to evaluate the fabric efficiency during the architecture enhancement as well as automate the design.

• Asia Marketing Journal
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• v.13 no.1
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• pp.113-141
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• 2011

Companies are competing each other, and as the competitions became higher, consumer's information processing for purchase became more complicated. Consumer confusion problem is getting more serious, but there are still not much considerations on this problem. The purpose of this study is to find out that the consumer confusion can causes consumer's negative emotion(anger). This research studied the mediation effect of negative emotion on the relationship between consumer confusion, which was classified into three categories, and two consequences, word-of-mouth and trust. And also it concentrates on moderating effects of negative affectivity and intolerance of uncertainty in the relationship between consumer confusion and negative emotion. For the empirical study, we carried out a survey targeting consumers who live in the Dae-gu metropolitan area. The specific results of this study are as follows. First, all sub-dimensions of the consumer confusion had a positive effect on anger. Second, anger had a positive effect on word of mouth and on the other hand, anger had a negative effect on trust. Third, negative affectivity had a moderating effects on the links between overload and ambiguity confusion with anger, and intolerance of uncertainty only had a moderating effects on the links between overload confusion and anger.

• Journal of KIISE:Software and Applications
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• v.31 no.3
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• pp.317-331
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• 2004

Recently software agent has been studied as a new abstraction unit of software engineering. The agent with autonomous, adaptability and cooperation attribute is accepted as a new abstraction unit especially in distributed systems, open systems, and complex systems. However, the progress of agent research has been slow and the realization of agent programming language seems to be far distant. Because the properties of agent are diverse, the opinions of researchers can not converge to one. In this situation, software agent framework is accepted more realistic alternative solution. However the knowledge for its development doesn't have been shared among developers. So they often have to make same errors. We will help sharing of knowledge and experience by using pattern language which has been used in object technology for long times. This paper proposes a reactive agent framework pattern language and validates it based on ATAM［l］ The increase of such indirect experience can reduce the waste of resource by preventing the same try and error. So agent framework developers are able to concentrate on more essential issues. Finally quality of software agent framework will be increased.

• Journal of Korea Multimedia Society
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• v.13 no.11
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• pp.1715-1727
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• 2010

Although a hand haptic interaction which provides direct and natural sensation is the most natural way of interacting with VR environment, the hand haptic interaction has still limitations with respect to the complexity of articulated hand and related hardware capabilities. Particularly, virtual assembly simulation which refers to the verification process of digital mockup in product development lifecycle is one of the most challenging topics in virtual reality applications. However, hand haptic interaction is considered as a big obstacle, because difficulty initial grasping and non-dextrous manipulation remain as unsolved problems. In this paper, we propose that common hand haptic interactions involves two separate stages with different aspects. We present the hand haptic interaction method enables us to stably grasp a virtual object at initial grasping and delicately manipulate an object at task operating by one's intention. Therefore, proposed method provides the robustness using grasping quality and dextrous manipulation using physically simulation. We conducted experiments to evaluate the effectiveness of our proposed method under different display environments -monoscopic and stereoscopic. From 2-way ANOVA test, we show that the proposed method satisfies two aspects of hand haptic interaction. Finally, we demonstrated an actual application of various assembly simulation for relatively complex models.

• Journal of Gifted/Talented Education
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• v.11 no.3
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• pp.23-44
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• 2001

In the current classrooms a teacher has been merely able to inculcate the procedural knowledge of how-and-what. In doing so, however, we lose sight of the essence of "doing science."Though desire of the gifted children is qualitatively different from that of normal children, it is an undesirable reality that we have not developed sufficient researches and programs in conformity with the necessary desire and demand of the gifted children. Curriculum for gifted children in the domain of science necessitates markedly the specializations for the specific areas of the contents, the processes, and the products of studies. In an effort to provide the optimum learning experience for the gifted, this paper deals with the development of project-and-discovery-based science program, its method of application to the real field of education, and its effect, however limited and partial that effect may be. What this study has found are the following: on the one hand, the students acquired and developed the higher levels of thinking when they were under the influence of project-and-discovery-based science program that dealt with concrete real-world problems and issues; on the other, the students were capable of solving creatively the complex and real problems through small group activities. This study also suggests the possible implications of project-and-discovery-based science program: the students can not only learn the contents of study but also apply them creatively; the students can cultivate critical thinking skills that can be a fundamental base for a life-time leaner; the students can naturally acquire the abilities of communication and coordination. Project-and-discovery-based program is currently used in the various disciplines. However, the field of gifted education does not yet implement this type of program. So the overall contribution of this study is to show the successful implementation of project-and-discovery-based science program in developing optimal teaming experience for gifted children in the domain of science, since this type of study is most compatible with the characteristic of the gifted children. children.

• Journal of the Korea Concrete Institute
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• v.14 no.3
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• pp.382-391
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• 2002

This study is devoted to the problems of thermal and shrinkage stresses in order to avoid cracking at early ages. The early-age damage induced by volume change has great influence on the long-term structural performance of the concrete structures such as its durability and serviceability To solve this complex problem, the computer programs for analysis of thermal and shrinkage stresses were developed. In these procedures, numerous material models are needed and the realistic numerical models have been developed and validated by comparison with relevant experimental results in order to solve practical problems. A framework has been established for formulation of material models and analysis with 3-D finite element method. After the analysis of the temperature, moisture and degree of hydration field in hardening concrete structure, the stress development is determined by incremental structural formulation derived from the principle of virtual work. In this study, the stress development is related to thermal and shrinkage deformation, and resulting stress relaxation due to the effect of early-age creep. From the experimental and numerical results it is found that the early-age creep p)ays important role in evaluating the accurate stress state. The developed analysis program can be efficiently utilized as a useful tool to evaluate the thermal and shrinkage stresses and to find measures for avoiding detrimental cracking of concrete structures at early ages.

• Tunnel and Underground Space
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• v.33 no.6
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• pp.594-609
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• 2023

TBM (Tunnel Boring Machine) method is gaining popularity in urban and underwater tunneling projects due to its ability to ensure excavation face stability and minimize environmental impact. Among the prominent models for predicting disc cutter life, the NTNU model uses the Cutter Life Index(CLI) as a key parameter, but the complexity of testing procedures and rarity of equipment make measurement challenging. In this study, CLI was predicted using multiple linear regression analysis and tree-based machine learning techniques, utilizing rock properties. Through literature review, a database including rock uniaxial compressive strength, Brazilian tensile strength, equivalent quartz content, and Cerchar abrasivity index was built, and derived variables were added. The multiple linear regression analysis selected input variables based on statistical significance and multicollinearity, while the machine learning prediction model chose variables based on their importance. Dividing the data into 80% for training and 20% for testing, a comparative analysis of the predictive performance was conducted, and XGBoost was identified as the optimal model. The validity of the multiple linear regression and XGBoost models derived in this study was confirmed by comparing their predictive performance with prior research.

• Journal of the Society of Disaster Information
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• v.10 no.4
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• pp.518-527
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• 2014

Our society is changed and diversified rapidly and such tendency is accelerated day after day and has made a lot of problems in the many fields. The important thing we have to recognize is such tendency has a bad effect recently on the safety system in Korea. So it is time to enhance the national safety system and moreover recently Sewol-ho(passenger ship) went down in the sea, it made people remind the importance of national safety system. With this incident, Korean government decided to establish the national safety communication network against the disaster. At this time, I will propose several ideas about the national safety communication network. 1. It must to be established an unified network to contact people who is on a disaster site anytime and anywhere. This is most important element on all disaster sites. 2. PS-LTE technology must to be adopted to the network because it has many advantages including various multimedia services compared to the TETRA in the past. 3. 700MHz is the most efficient band for the network because it has wide cell sites coverage compared to 1.8GHz. 4. Satellite communication system is needed to the network for back-up. 5. It will be effective to adopt Social Media to the communication network system like a Twitter or Facebook for sharing many kinds of information and notifying people of warning message. 6. It can make the network more useful to introduce the latest technology like a sensor network. And Korean government has to improve the system related to the disaster including law and operating organization.

• The Journal of the Korea Contents Association
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• v.17 no.3
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• pp.654-665
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• 2017

It is major strategy for SMEs to cooperate with other companies or Public Research Institutes(PRIs) as the essential technology is getting more complicated and technological life cycle is getting short. However, It is not easy to perform a proper cooperation with SMEs for PRIs, because they are accustomed to support SMEs in the short run. In addition, previous studies also have mainly focussed on finding determinants of performance as a consequence of temporary cooperation instead of long-term relationships among companies. Therefore this study analyzed which satisfaction is more effective to maintain the long-term cooperative relationship between PRIs and SMEs. As a result, it has found that when SMEs satisfy from quality of input like manpower supports R&D and context of the support program over the output like technological or economical performance, they intend to continue cooperation with PRIs. And this paper shows that the performance has mediated effect rather direct effect on long-term cooperation intention. In light of all the above, to cooperate with SMEs effectively, it will be suggested that PRIs enhance quality of support process and contents instead of quantity of support based on one-time cooperation.