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Experimental and Numerical Study of the Thermal Decomposition of an Epoxy-based Intumescent Coating (실험과 계산을 통한 에폭시 계열 내화도료의 열분해에 관한 연구)

  • Kim, Yangkyun
    • Fire Science and Engineering
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    • v.30 no.1
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    • pp.31-36
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    • 2016
  • This study investigates the characteristics of thermal decomposition of an epoxy-based intumescent paint using thermogravimetric analysis (TGA) and numerical simulation. A mathematical and numerical model is introduced to describe mass loss profiles of the epoxy-based intumescent coating induced by the thermal decomposition process. The decomposition scheme covers a range of complexity by employing simplified 4-step sequential reactions to describe the simultaneous thermal decomposition processes. The reaction rates are expressed by the Arrhenius law, and reaction parameters are optimized to fit the degradation behavior seen during thermogravimetric (TG) experiments. The experimental results show a major 2-step degradation under nitrogen and a 3-step degradation in an air environment. The experiment also shows that oxygen takes part in the stabilization of the intumescent coating between 200 and $500^{\circ}C$. The simulation results show that the proposed model effectively predicts the experimental mass loss as a function of time except for temperatures above $800^{\circ}C$, which were intentionally not included in the model. The maximum error in the simulation was less than 3%.

A Research on the Uses of Storytelling Approach for Architecture (건축분야에서의 스토리텔링 기법 활용방안 연구)

  • Yoon, Ki-Byung
    • Journal of the Korean housing association
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    • v.18 no.1
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    • pp.53-60
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    • 2007
  • Storytelling approach is the way to formulate and solve problems using stories. Story is a means to understand and react everyday life that can be regarded as multi-dimensional problems. The approach becomes popular in various fields in conjunction with digital technology. In particular, it is used to solve problems in relation to whole context. In design, storytelling approach is used to clarify design constraints. It can be used to clarify and communicate thoughts for design artifacts, and to understand how the artifacts might be used in particular circumstances. In particular, the approach is useful to use under uncertain circumstances. In architecture, storytelling approach can be used in the area of design generation, design critique and capturing design knowledge. In design generation, it can be used to describe and formulate design experiences rather than simple designing artifacts. The approach formalizes design based on stories of user experiences. Digital technology such as virtual reality can be used to experience designed spaces for design modifications. In design critique area, it can be used to fill uncertain facts for historical buildings as welt as different from present status. Such stories can be used to build digital modeling and used to open criticism. Stories can be used to formalize knowledge in architectural domain as a form of implicit knowledge for certain projects. In architecture, it often is required to design types of environment never experienced before as well as to accomodate fast changing technologies. Storytelling methodology can be used as a method to cope with uncertainty and complexity in design requirements along with accumulating design knowledge.

An Analysis of Nursing Decision Tasks, Characteristics, and Problems with Decision Making (환자 간호에 대한 간호사의 의사결정 내용과 특성 및 의사결정 장애요인에 관한 분석)

  • 최희정
    • Journal of Korean Academy of Nursing
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    • v.29 no.4
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    • pp.880-891
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    • 1999
  • The purpose of this study was to describe nursing decision tasks, their characteristics, and problems associated with decision making. The subjects were 32 nurses who had at least one-year nursing experience and worked on medical-surgical units or intensive care units(ICU). They were asked to describe their decision making experiences in patient care situations and to identify the characteristics of each decisions. They were also asked to describe perceived problems associated with decision making in nursing. The responses on nursing decision tasks and problems were analyzed with content analysis and the decision characteristics were identified by statistical analysis of variance. It was found that there were 16 nursing decisions which are as follows : decisions related to interpreting and selecting appropriate strategies for pain management(6.6%) ; decisions related to providing emotional support (0.7%) ; decisions related to explaining the patient's condition and rationale for procedures(1.1%) ; decisions related to assisting patients to integrate the implications of illness and recovering into their lifestyles(2.9%) ; decisions related to detecting significant changes In patients and selecting appropriate intervention strategies (17.2%) ; decisions related to anticipating problems and selecting preventive measures(4.2%) ; decisions related to identifying emergency situations(0.4%) ; decisions related to effective management of patient crisis until physician assistance becomes available(2.8%) ; decisions related to starting and maintaining intravenous therapy(2.6%) ; decisions related to administering medications(8.1%) ; decisions related to combating the hazards of immobility(7.3%) : decisions related to treating wound management strategies(5.5%) ; decisions related to relieving patient discomfort(13.9) ; decisions related to selecting appropriate strategy according to the changing situation of the patient(18.2%) ; decisions related to selecting the best strategy for patient management(5.3%) ; and decisions related to coordinating, ordering, and meeting the various needs of the patient (3.1%). The nurses reported the fellowing problems in decision making : difficulties due to lack of knowledge and experience (18.6%) ; uncertainty and complexity of decision tasks(15.2%) ; lack of time to make decisions(2.9%) ; personal values which conflict with other staff(15.7%) ; lack of selection autonomy(30.0%) ; and organizational barriers(7.6%). Continuing education programs and decision support systems for frequent nursing decision tasks can be established on the basis of these results. Then decision ability in nurses will increase through the education programs and decision support systems, and then quality of nursing service will be better.

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Improvement of FTA for Completeness, Review and Knowledge Transfer - Introducing Strategy and Context Nodes in GSN and Reason Node -

  • Yoshioka, Nasa;Shirasaka, Seiko
    • Journal of the Korean Society of Systems Engineering
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    • v.11 no.2
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    • pp.125-135
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    • 2015
  • Various methods have been used for safety and reliability as it becomes more difficult to ensure safety owing to the increasing complexity and scale of systems. This study aims at making it easier and more efficient to discuss risks and countermeasures for completeness, review, and knowledge transfer by improving methods to create fault tree analyses which focus on the GSN [1], which are among the methods used to describe assurance cases. More specifically, the purpose of this study is to incorporate strategy and context, GSN concepts, along with reason, which is a new concept, into FTA; the study focuses on three points. One point is support for the safety designer to draw a mutually exclusive and collectively exhaustive (MECE) FTA. The second is to make it easier to understand diagrams and meanings of FTA compared with the usual methods. The third is to make creating an FTA more efficient and to pass on existing know-how. Eventually, FTA can achieve completeness, review, and knowledge transfer. An introduction is provided in the first section. Next, the methodology covered in this paper is explained in the second section. The third section describes the proposed notation method based on two proposals made in this paper. In the fourth and fifth sections, results and discussion are provided, respectively. Finally, in the sixth section, conclusions are described.

Appling of Force Control of the Robotic Sweeping Machine for Grinding (연마작업을 위한 로봇형 연마기의 힘제어 적용)

  • Jin, Taeseok
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.2
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    • pp.276-281
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    • 2014
  • In this research, we describe a force feedback control for industrial robots has been proposed as a system which is suitable to work utilizing pressure sensitive alternative to human. Conventionally, polished surface of the workpiece are recognized, chamfer ridge, machining processes such as deburring, and it is most difficult to automate because of its complexity, has been largely dependent on the human. To aim to build automatic vacuum system robotic force control was gripping the grinding tool, the present study we examined the adaptability to the polishing process to understand the characteristics of the control system feedback signal obtained from the force sensor mainly. Furthermore, as a field, which holds the key to the commercialization, I went ahead with the application to robotic sweeping machine. As a result, the final sweeping utilizing a robot machine to obtain a very good grinded surface was revealed.

A Novel Framework for Defining and Submitting Workflows to Service-Oriented Systems

  • Bendoukha, Hayat;Slimani, Yahya;Benyettou, Abdelkader
    • Journal of Information Processing Systems
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    • v.10 no.3
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    • pp.365-383
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    • 2014
  • Service-oriented computing offers efficient solutions for executing complex applications in an acceptable amount of time. These solutions provide important computing and storage resources, but they are too difficult for individual users to handle. In fact, Service-oriented architectures are usually sophisticated in terms of design, specifications, and deployment. On the other hand, workflow management systems provide frameworks that help users to manage cooperative and interdependent processes in a convivial manner. In this paper, we propose a workflow-based approach to fully take advantage of new service-oriented architectures that take the users' skills and the internal complexity of their applications into account. To get to this point, we defined a novel framework named JASMIN, which is responsible for managing service-oriented workflows on distributed systems. JASMIN has two main components: unified modeling language (UML) to specify workflow models and business process execution language (BPEL) to generate and compose Web services. In order to cover both workflow and service concepts, we describe in this paper a refinement of UML activity diagrams and present a set of rules for mapping UML activity diagrams into BPEL specifications.

Beyond Factual Knowledge and Symbolic Competence: Interculturality as Transcultural Intersubjectivity

  • Omengele, Theophile Ambadiang
    • Cross-Cultural Studies
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    • v.20
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    • pp.295-321
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    • 2010
  • The trend of globalization has sharpened the debate on interculturality, which scholars examine from different and often conflicting points of view ('content' vs. 'practice', 'culture-specific' vs. 'universal', 'communication (meta)theory' vs. 'communication practice', 'individual' vs. 'collective', etc.). Whereas all these approaches are necessary to describe the multiple dimensions of interculturality, their dichotomous nature does not help to account for its internal complexity, which cannot be dissociated from the connections that exist among all these dimensions. The difficulty posed by the essentialist interpretations that tend to result from these dichotomies is compounded by the fact that in postmodern debates priority has been given to approaches that emphasize individual or collective agency over structural constraints which have to do with political economy or with cultural and linguistic codes and traditions. This paper aims mainly at suggesting that the dissolution of the boundaries that exist between these approaches should be pursued in order to get a fuller and richer approach to their common object of study. After discussing, by way of illustration, content-based and practice-based perspectives, we suggest that one way of getting beyond these dichotomies consists in focusing on the 'interactional' dimension of interculturality, which means laying emphasis on intersubjectivity and, particularly, on the individual subjects considered as members of different cultural communities who strive to transcend their sociocultural boundaries in order to reach harmonious interactions in a world in which inequality and the de-territorialization of people and cultures are central features.

Investigation of blasting impact on limestone of varying quality using FEA

  • Dimitraki, Lamprini S.;Christaras, Basile G.;Arampelos, Nikolas D.
    • Geomechanics and Engineering
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    • v.25 no.2
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    • pp.111-121
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    • 2021
  • Large deformation and rapid pressure propagation take place inside the rock mass under the dynamic loads caused by the explosives, on quarry faces in order to extract aggregate material. The complexity of the science of rock blasting is due to a number of factors that affect the phenomenon. However, blasting engineering computations could be facilitated by innovative software algorithms in order to determine the results of the violent explosion, since field experiments are particularly difficult to be conducted. The present research focuses on the design of a Finite Element Analysis (FEA) code, for investigating in detail the behavior of limestone under the blasting effect of Ammonium Nitrate & Fuel Oil (ANFO). Specifically, the manuscript presents the FEA models and the relevant transient analysis results, simulating the blasting process for three types of limestone, ranging from poor to very good quality. The Finite Element code was developed by applying the Jones-Wilkins-Lee (JWL) equation of state to describe the thermodynamic state of ANFO and the pressure dependent Drucker-Prager failure criterion to define the limestone plasticity behavior, under blasting induced, high rate stress. A progressive damage model was also used in order to define the stiffness degradation and destruction of the material. This paper performs a comparative analysis and quantifies the phenomena regarding pressure, stress distribution and energy balance, for three types of limestone. The ultimate goal of this research is to provide an answer for a number of scientific questions, considering various phenomena taking place during the explosion event, using advanced computational tools.

Married Female Migrants' Experiences of Health Care Services (여성결혼이민자의 의료서비스 이용경험)

  • Koh, Chin-Kang;Koh, Sun-Kang
    • The Journal of Korean Academic Society of Nursing Education
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    • v.15 no.1
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    • pp.89-99
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    • 2009
  • Purpose: The purpose of this study was to describe married female migrants' experiences of health care services and to help nursing researchers, nursing educators, and clinical nurses understand married female migrants' experiences. Method: A conventional content analysis method was utilized. Individual in-depth interviews with 15 married female migrants were conducted. Subject recruitment was performed at a district in Seoul. Results: Ten categories were induced: language barrier, financial burden, insufficient time with a physician, complexity of utilization process, lack of support from peer group, health care providers' discrimination, anxiety regarding lack of information about children's health, health care providers' concerns and efforts to minimize the language barrier, family support, and advanced health care service environment. Conclusion: This study provides basic knowledge regarding married female migrants' experiences related to health care services. Future research should designate and utilize valid instruments to measure the positive and negative experiences and to explore strategies to strengthen the positive features while eliminating the negative ones. Finally, the Korean nursing education curriculum should include cultural competence and knowledge about an ethnic minority's right to health service utilization.

Motivation based Behavior Sequence Learning for an Autonomous Agent in Virtual Reality

  • Song, Wei;Cho, Kyung-Eun;Um, Ky-Hyun
    • Journal of Korea Multimedia Society
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    • v.12 no.12
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    • pp.1819-1826
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    • 2009
  • To enhance the automatic performance of existing predicting and planning algorithms that require a predefined probability of the states' transition, this paper proposes a multiple sequence generation system. When interacting with unknown environments, a virtual agent needs to decide which action or action order can result in a good state and determine the transition probability based on the current state and the action taken. We describe a sequential behavior generation method motivated from the change in the agent's state in order to help the virtual agent learn how to adapt to unknown environments. In a sequence learning process, the sensed states are grouped by a set of proposed motivation filters in order to reduce the learning computation of the large state space. In order to accomplish a goal with a high payoff, the learning agent makes a decision based on the observation of states' transitions. The proposed multiple sequence behaviors generation system increases the complexity and heightens the automatic planning of the virtual agent for interacting with the dynamic unknown environment. This model was tested in a virtual library to elucidate the process of the system.

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