• The Journal of Advanced Prosthodontics
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• v.10 no.2
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• pp.113-121
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• 2018

PURPOSE. The aim of this preliminary study was to investigate, for the first time, the effects of addition of titania nanotubes ($n-TiO_2$) to poly methyl methacrylate (PMMA) on mechanical properties of PMMA denture base. MATERIALS AND METHODS. $TiO_2$ nanotubes were prepared using alkaline hydrothermal process. Obtained nanotubes were assessed using FESEM-EDX, XRD, and FT-IR. For 3 experiments of this study (fracture toughness, three-point bending flexural strength, and Vickers microhardness), 135 specimens were prepared according to ISO 20795-1:2013 (n of each experiment=45). For each experiment, PMMA was mixed with 0% (control), 2.5 wt%, and 5 wt% nanotubes. From each $TiO_2$:PMMA ratio, 15 specimens were fabricated for each experiment. Effects of $n-TiO_2$ addition on 3 mechanical properties were assessed using Pearson, ANOVA, and Tukey tests. RESULTS. SEM images of $n-TiO_2$ exhibited the presence of elongated tubular structures. The XRD pattern of synthesized $n-TiO_2$ represented the anatase crystal phase of $TiO_2$. Moderate to very strong significant positive correlations were observed between the concentration of $n-TiO_2$ and each of the 3 physicomechanical properties of PMMA (Pearson's P value ${\leq}.001$, correlation coefficient ranging between 0.5 and 0.9). Flexural strength and hardness values of specimens modified with both 2.5 and 5 wt% $n-TiO_2$ were significantly higher than those of control ($P{\leq}.001$). Fracture toughness of samples reinforced with 5 wt% $n-TiO_2$ (but not those of 2.5% $n-TiO_2$) was higher than control (P=.002). CONCLUSION. Titania nanotubes were successfully introduced for the first time as a means of enhancing the hardness, flexural strength, and fracture toughness of denture base PMMA.

• Journal of the Korean GEO-environmental Society
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• v.7 no.6
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• pp.101-111
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• 2006

In case of drilled shafts installed by drilling through soft overburden onto a strong rock, the piles can be regarded as end-bearing elements and their working load is determined by the safe working stress on the pile shaft at the point of minimum cross-section or by code of practice requirements. Drilled shafts drilled down for some depth into weak or weathered rocks and terminated within these rocks act partly as friction and partly as end-bearing piles. The base resistance component can contribute significantly to the ultimate capacity of the pile. However, the shaft resistance is typically mobilized at considerably smaller pile movements than that of the base. In addition, the base response can be adversely affected by any debris that is left in the bottom of the socket. The reliability of base response therefore depends on the use of a construction and inspection technique which leaves the socket free of debris. This may be difficult and costly to achieve, particularly in deep sockets, which are often drilled under water or drilling slurry. As a consequence of these factors, shaft resistance generally dominates pile performance at working loads. The efforts to improve the prediction of drilled shaft pile performance are therefore primarily concerned with the complex mechanisms of shaft resistance development. In this study, the numerical analyses are carried out to investigate the behavior characteristics of side of rock socketed drilled shafts varying the loading condition at the pile head. The difference of behavior characteristics of side resistance is also evaluated with the effects of modelling of asperity.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.8
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• pp.543-554
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• 2013

Model-Driven Development(MDD) helps developers verify requirements and design issues of a software system in the early stage of development process by taking advantage of a software model which is the most highly abstracted form of a software system. In practice, however, many software systems have been developed through a code-centric method that builds a software system bottom-up rather than top-down. So, without support of appropriate tools, it is not easy to introduce MDD to real development process. Although there are many researches about extracting a model from code to help developers introduce MDD to code-centrically developed system, most of them only extracted base-level models. However, using concept of abstract component one can continuously extract higher level model from base-level model. In this paper we propose a practical method for automatic extraction of base level abstract component from source code, which is the first stage of continuous extraction process of abstract component, and validate the method by implementing an extraction tool based on the method. Target code chosen is the source code of TinyOS, an operating system for wireless sensor networks. The tool is applied to the source code of TinyOS, written in nesC language.

• Journal of Technology Innovation
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• v.20 no.2
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• pp.109-134
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• 2012

In this era of globalization and fierce competition, R&D is an essential part of corporate development strategy. Accordingly, much effort has been devoted to identify and verify best practices for successful R&D and to improve R&D processes. Nevertheless, there is still lack of a comprehensive framework for assessing the quality of R&D process, which can be used as a step-by-step guide for process improvement. Therefore, this study purposes to develop a framework for assessing R&D process based on the concept of CMMI, which is a process improvement approach that defines the essential elements of effective processes. In particular, we suggest three types of R&D process-new product development, new service creation and new technology creation-and then develop a customized framework for them. For this purpose, we firstly investigated the characteristics of R&D activities for each type of process and identify its base practices from an extensive literature review. Then, the CMMI approach was adopted and modified to suit the R&D process. Finally, an illustrative example was provided to demonstrate the assessment process and a prototype web-based assessment system was suggested. Research findings will help understand the characteristics of different types of R&D process and provide a customized guidelines for R&D process assessment and improvement.

• Water Engineering Research
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• v.3 no.2
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• pp.85-92
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• 2002

There has been continuous efforts to manage water resources for the required water quality criterion at river channel in Korea. However, we could obtain the partial improvement only for the point sources such as, waste waters from urban and factory site through the water quality management. Therefore, it is strongly needed that the best management practice throughout the river basin fur water quality management including non-point sources pollutant loads. This problem should be resolved by recognizing the non-point sources pollutant loads from the upstream river basin to the outlet of the basin depends on the landuse and soil type characteristics of the river basin using the computer simulation by a distributed model based on the detailed investigation and application of Geographic Information System (GIS). The purpose of this study is consisted of the three major distributions, which are the investigation of spread non-point sources pollutants throughout the river basin, development of the base maps to represent and interpret the input and outputs of the distributed simulation model, and prediction of non-point sources pollutant loads at the outlet of a up-stream river basin using Agricultural Non-Point Sources Model (AGNPS). For the validation purpose, the Seom-Jin River basin was selected with two flood events in 1998. The results of this application showed that the use of combined a distributed model and an application of GIS was very effective fur the best water resources and quality management practice throughout the river basin

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.6
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• pp.65-71
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• 2010

The aim of the study intends to investigate wearing practice of personal protective equipment for firefighter in gyeongnam province and to provide the base data for the safety and health of firefighter. The results of the study are as follows. The overall reliability of fire personal protection equipment has been investigated by 3.19 and an overall improvement in the personal protective equipment is needed. Firefighter showed such a low satisfaction leather fire boots(2.68), glove(2.67) and rubber fire boots(2.59) in personal protective equipment and rubber fire boots(2.75), glove(2.77) and leather fire boots(2.97) has been investigated by the state of the poor. For personal protective equipment, firefighters have been experiencing many difficulties on the fit and weight. To overcome this problem, it is necessary to be designed ergonomically and to develop high-performance, lightweight materials.

• International Journal of Automotive Technology
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• v.7 no.1
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• pp.83-90
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• 2006

The purpose of this paper is to describe the design and implementation of an unmanned ground vehicle, called the TailGator at CIMAR (Center for Intelligent Machines and Robotics) of the University of Florida. The TailGator is a gas powered, four-wheeled vehicle that was designed for the AUVSI Intelligent Ground Vehicle Competition and has been tested in the contest for 2 years. The vehicle control model and design of the sensory systems are described. The competition is comprised of two events called the Autonomous Challenge and the Navigation Challenge: For the autonomous challenge, line following, obstacle avoidance, and detection are required. Line following is accomplished with a camera system. Obstacle avoidance and detection are accomplished with a laser scanner. For the navigation challenge, waypoint following and obstacle detection are required. The waypoint navigation is implemented with a global positioning system. The TailGator has provided an educational test bed for not only the contest requirements but also other studies in developing artificial intelligence algorithms such as adaptive control, creative control, automatic calibration, and internet-base control. The significance of this effort is in helping engineering and technology students understand the transition from theory to practice.

• Journal of Korean Academy of Nursing Administration
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• v.5 no.1
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• pp.181-195
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• 1999

This study was done to develope a computer program for the evaluation of quality of nurisng care. Because the professional nursing care should be evaluated consistantly, computer program for the measurement of quality of nursing care is necessary for the effective and efficient management of nursing quality. In this study, a computer program for gastrointestinal surgery patients was developed as a module. Visual basic 4.0 was used as a basic program for the development of this program, and Access 7.0 was used for the data base construction of the program. The systems of evaluation criteria were hierarchical. and the titles of the hierarchical criteria were evaluation area-evaluation item-indicator. Each evaluation area contained several items and each evaluation item contained several indicators. The numbers of the evaluation criteria for gastrointestinal surgery patients were 7 evaluation areas, 32 evaluation items. and 71 indicators. Content validity of the evaluation criteria(in this case, 32 evaluation items) was .95. Scoring could be possible with the evaluation items. For the scoring types of this program were two. norm-referenced type(option 1) and criterion-referenced type(option 2), the user can choose the type according to the purpose of the evaluation. With this computer program. accurate and consistant evaluation of the quality of nursing care could be expected. Also. by the rapid feedback to nursing care practice. quality of nursing practice could be improved rapidly. and the systems of the evaluation criteria developed in this study could be used for the development of other moduls for various kinds of patient groups. Because this computer program was developed only for the purpose of research, it is necessary to be refined commercially to be used in real nursing situation.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.2 no.1
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• pp.55-66
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• 1995

The goals of nursing education, and the bases for evaluating them depend on the goals of nursing practice. In order to prepare for the coming twenty first century and the meet changing societal demands and health needs, it is necessary to develop a new conceptual framework for future nursing education. While hospitals will still be in significant components of the health care system, will no longer be central focus or dominant influence. Health care services will be more usually delivered at community base. The nursing education required by that new approach must provide for reconsidered about a concept of caring as nursing curriculum. The changes in health care delivery that have occured, now being proposed, for nursing education undergoing its own changes. So the philosophy and objectives of education meed to reconsidering about the caring concept and general nursing. Nurse educators must prepare students to practic in condition of constant change. At the same time nurse educators must emphasize preparation about that. The practice of science of caring in nursing draws on a basic knowledge of the behavioral knowledge, biophysical processes, pathological processes, nursing skills and procedures and various treatment regimes and problem solving to help decision making in nursing situations. The concept of care is probably one of the least understood ideas used by professional and nonprofessional people, yet it is probably one of the most improtant concepts to be understood by nursing. Human caring and human relationships are closely interrelated. Humn caring remains an essential dimension of professional work and the science of caring as essental to the discipline of nursing. It is expected that the objectives of nursing education will be accomplished when the course and content of the curriculum are based on this conceptual framework. One recurrent education goal with some consistency is that of equipping the student with the necessary skills to live effectively and productivly in the world of tomorrow. In the new vision we are developing, professional education must also include exposure to liberal arts, encouragement of critical thinking, and a moral context for advanced professional education that is based upon a contextual health policy and caring science educational model.

• Journal of Fisheries and Marine Sciences Education
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• v.10 no.1
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• pp.100-113
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• 1998

The information society is characterized by rapidly increasing and changing information. Traditional models of learning and instruct on have emphasized forms of mastering the information in content domains. Storing information and being able to recall it has been central to formal education. But it is no longer possible to master content domains. This paper discusses constructivism as a shifting paradigm for educational research and practice in information society. Constructivism provides an alternative epistemological base to the objectivist tradition. Constructivism holds that there is a real world that we experience. However, the argument is that meaning is imposed on the world by us, rather than existing in the world independently of us. Meaning is seen as rooted in experience. The experience in which an idea is embedded is critical to the individual's understanding of that idea. From the constructivist perspective, learning is not a stimulus-response phenomenon. It requires self-regulation and the building of conceptual structures through reflection and abstraction. Problems are not solved by the retrieval of rote-learned right answers. The effective motivation to continue learning can be fostered by leading students to experience the pleasure that is inherent in solving problems chosen as one's own. Constructivism requires the change of the teacher's role from a knowledge transmitter to a coach or facilitator of student's understanding. Constructivist teachers inquire about students' understanding of concepts before sharing their own understandings of those concepts, and encourage students to engage in dialogue, both with them arid with one another. In Korea, the educational reform called open education has been spreading through out the country. There should be a paradigm shift in learning and instruction from objectivism to constructivism for better educational reform in Korea.