• Communications of the Korean Mathematical Society
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• v.20 no.2
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• pp.321-338
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• 2005

In this paper we investigate a generalization of the Hyers-Ulam-Rassias stability for a functional equation of the form $f(\varphi(X))\;=\;\phi(X)f(X)$, where X lie in n-variables. As a consequence, we obtain a stability result in the sense of Hyers, Ulam, Rassias, and Gavruta for many other equations such as the gamma, beta, Schroder, iterative, and G-function type's equations.

• Journal of Korean Biological Nursing Science
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• v.2 no.2
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• pp.53-66
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• 2000

Objectives: The studies in biological, behavioral and psychosocial perspectives in nursing research are fundamental in the balanced development of nursing knowledge. Many nursing researchers have placed a strong emphasis on developing psychological and behavioral aspects of nursing knowledge as is evidenced by the large body of research in these areas. However, the paucity of nursing research using the principles of biological science for measurements and techniques have often invited open criticism by many nursing researchers. This study attempts to characterize the researches performed in master and doctoral thesis which used physiological variables. Methods: We analyzed masters' thesis from 1962 to 1996 and doctoral thesis from 1982 to 1996 listed in CD from Korean Nurses Association. Results: Out of 3060 masters' thesis from 1962 to 1996, 342 (11.2%) thesis used physiological variables whereas 43 (10.1%) doctoral thesis used physiological ones. Number of thesis with physiological variables was the highest in Seoul National University for masters' thesis whereas for the doctoral thesis the number was the highest in Yonsei University. The research subjects in these thesis with physiological variables were mostly patients (53.5% in masters' and 69.8% in doctoral). Master's thesis often conducted either nonexperimental or survey research (69.9%) whereas experimental research design prevailed vital signs(181 thesis), blood tests(133), body composition(124), microorganisms(74), gastrointestinal functions(36), lab test(33), drug(21), urinary functions(20), movement(17), Apgar Score(15), reproductive functions(9), skin related functions(6), body fluid and electrolytes(4), parasite(4), metabolism(3), and sensory(1), Among the 338 master' thesis which studied the common nursing concepts such as anxiety, pain, stress, and depression, 48(14.2%) thesis utilized physiological variables while 15 out of 35 doctoral thesis addressed these concepts using physiological variables. Conclusion: In summary, our results indicate that despite the large amount of nursing research performed over the last decades, there are a few nursing researches done with physiological variables either in masters' or doctoral thesis. To enrich nursing knowledge with different perspectives of nursing including especially biological ones, the efforts have to be made to conduct bionursing science research.

• Progress in Medical Physics
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• v.13 no.3
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• pp.129-134
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• 2002

The radiosurgery is planned that prescribed dose was irradiated to tumor for obtaining expected remedial value in stereotactic radiosurgery. The planning for many irregular tumor shape requires long computation time and skilled planners. Due to the rapid development in computer power recently, many optimization methods using computer has been proposed, although the practical method is still trial and error type of plan. In this study, many beam variables were considered and many tumor shapes were assumed cylinderical ideal models. Then, beam variables that covered the target within 50％ isodose curve were searched, the result was compared and analysed. The beam variables considered were isocenter separation distance, number of isocenters and collimator size. Dose distributions obtained with these variables were analysed by dose volume histogram(DVH) and dose profile at orthogonal plane. According to the results compared, the use of more isocenters than specified isocenter dosen't improve DVH and dose profile but only increases complexity of plan. The best result of DVH and dose profile are obtainedwhen isocenter separation was 1.0-1.2 in using same number of isocenter.

• The Korean Journal of Applied Statistics
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• v.27 no.1
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• pp.31-41
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• 2014

Biplot is a useful graphical method to simultaneously explore the rows and columns of a two-way data matrix. In particular, principal component factor biplot is a graphical method to describe the interrelationship among many variables in terms of a few underlying but unobservable random variables called factors. If we consider the unobservable variables (which are mutually independent and also non-Gaussian), we can apply the independent component analysis decomposing a mixture of non-Gaussian in its independent components. In this case, if we apply the principal component factor analysis, we cannot clearly describe the interrelationship among many variables. Therefore, in this study, we apply the independent component analysis of Jutten and Herault (1991) decomposing a mixture of non-Gaussian in its independent components. We suggest an independent component biplot to interpret the independent component analysis graphically.

• Journal of Korean Academy of Nursing
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• v.23 no.4
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• pp.694-712
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• 1993

A number of nursing researchers have used the concept of health locus of control over the past decade in Korea. This article reviewed 92 nursing research papers on health locus of control conducted since 1982, and examined type of subjects, design, measurement instruments, the scores of each dimension of the HLOC, and significant variables. Most of the research were correlational in design, used an 18-item 6-point score instrument and studied the relationship between HLOC, health re-lated variables, and cognitive-emotional variables, The health related variables included health behavior, health management, preventive health behavior, compliance to treatment regimen and self care behavior The cognitive-emotional variables included depression, anxiety, stress and self- esteem. Some consistent findings are beginning to emerge. The concept of internal HLOC was positively correlated with the health related variables. But few studies found any significant correlation between powerful others HLOC and health related variables. In the case of chance HLOC, few studies reported a significant relationship. Many of the articles reported significant relationships between internal HLOC and cognitive-emotional variables, but few reported a significant relationship between powerful others or chance HLOC and cognitive -emotional variables. all experimental studies but one found that only internal HLOC was significantly changed following experimental manipulation. When the different groups of subjects such as normal persons, chronic patients, acute patients were compared in terms of mean scores, it was found that the HLOC appeared to change depending on the status of the patients. Recommendations for future research include modification of the instrument to increase the reliability and validity, study about the pattern of response suggested by Wallston and Wallston(1982) and further experimental study on changing the belief of subjects to internal HLOC.

• Journal of the Korean Society of Safety
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• v.30 no.4
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• pp.151-158
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• 2015

Usually risk assessment is performed for the safety of diverse industries though, many kinds of risks cannot be analyzed effectively by using classical probability models due to lack of experience data and impreciseness of human decision making. For these reasons, fuzzy risk assessment utilizing subjective judgment and experience of skillful experts has been considered as a solution. In this study, to comprehend the relationship between conventional fuzzy theory and human conceptual images on risks, linguistic variables were reviewed with reference to fuzzy membership functions, especially in the Korean language. As interviewees, about a hundred people including students as well as safety engineers voluntarily participated. The research results showed that most people were in favor of adjective expressions decorated with adverbs rather than naive expressions such as "high" or "low", and that directly translated linguistic variables were not appropriate for the Korean people in risk assessment as far. Therefore, with consideration of the selection tendency by the Korean people in linguistic variables, it could be concluded that 5 level expressions would be most favorable for linguistic variables in risk assessments in Korea.

• Journal of the Korean Institute of Landscape Architecture
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• v.22 no.2
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• pp.81-103
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• 1994

In recent years, the visual characteristics of natural open space and greenbelt surrounding the urban landscapes have been changed with sprawling of residential areas and highrised residential buildings. Since these natural areas being the background element of residential areas are topographically sloped mountains in many cities. It is easy to be seen in the distance and it is important to preserve these areas as a visual infrastructure of the urban landscape. The purposes of this study are to extract the factors of landscape impact evaluation for these areas and to clarify the physical landscape variables representing these factors, and to infer the visual-perceptional relationships between image and landscape variables. As results, conceptional three factors were extracted with semantic differential evaluation to classified 18 landscape slide, and three regression models were established with factor score of landscapes and physical variables measured in photographs. On the basis of these relationships, visual-perceptional characteristics were discussed by analyzing the data form eye-movement recording to each of landscapes. The factors of "spatial unfolding of backdropped hilly greenspace", "horizontal quence of residential buildings", and "landscape complexity" prove to be important. And it prove important variables of "skyline of mountainous ridge" and "visual edge of building structure" in regression models and eye fixation movements.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.5
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• pp.16-25
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• 2009

Testing engine performance using an engine dynamometer requires high technical researchers and many facilities. Nowadays, different variables of CAE program are used for identifying the engine performance instead of engine dynamometer test. This is more convenience, as it does not necessitate an abundance of engine dynamometer experiments and, in addition, produces better results. However, CAE programs also contain various variables which can affect engine performance. Those are coupled with each other, thus making it difficult to determine the effectiveness of different variables on engines. DoE (Design of Experiments) methodology is an efficient way to verify the magnitude of effectiveness on engine performance as well as making responses to be optimized at once without trial & error. This study used data from WAVE simulations, which modeled the DOHC SI engine with in-line 4 cylinders at 1500, 3000 and 4500rpm. DoE methodology is designed properly to determine the effectiveness of five variables on power, BSFC, and volumetric efficiency, as well as to find the optimal response conditions at each rpm through a minimized number of experiments. After finishing DoE process, all the results are examined concerning the reliability of test through a verification experiment.

• Journal of Korean Institute of Industrial Engineers
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• v.22 no.2
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• pp.265-276
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• 1996

Multimedia systems present information by various media, for example, video, sound, music, animation, movie, etc., in addition to the text which has long been used for conveying the information. Among many multimedia applications, the multimedia information retrieval systems commercialized in the forms of multimedia encyclopedia CD-ROMs, benefited from various media for their ability to present information in an efficient and complete way. But using several media, on the other hand, may cause end users' confusion and furthermore, poorly designed user interface often exacerbates the situation. In this study, the multimedia systems were studied from the standpoint of usability. The conceptual framework of the user interface of the multimedia system was newly defined. And 100 initial variables for user interface design of general multimedia systems were suggested through literature survey and expert opinions based upon the framework developed. Among various application areas, the multimedia information retrieval systems were chosen for investigation, and 36 variables particularly relevant to user interface of the multimedia information retrieval systems were selected. According to the sequential research strategy, the variables that were considered to be most important were finally selected through a screening stage. A part of selected variables were verified through a human factors experiment as the first step of sequential research. Based upon the result of the experiment, guidelines for user interface design were provided. For future study, the variables remained will be Investigated and the study will expand to another application areas.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.7
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• pp.742-752
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• 2009

Engineering design involves the specification of many variables that define a product, how it is made, and how it behaves applied to computer, communication and control fields. Before some variables can be determined, other variables must first be known or assumed. This fact implies a precedence order of the variables, and of the tasks of determining these variables consequently. Moreover, design of complex systems may involve a large number of design activities. In this paper, the activity-activity incidence matrix is considered as a representation of design activity analysis which mainly focuses on the precedence constraint with an object of doing IDEF3 in process-centered view. In order to analyze the activity-activity incidence matrix, a heuristic algorithm is proposed, which transforms an activity-activity, parameter-formula, and parameter-parameter incidence matrix into a lower triangular form. The analysis of the structured matrices can not only significantly reduce the overall project complexity by reorganizing few critical tasks in practice, but also aims at obtaining shorter times considering the solution structure by exploring concurrency.