• Investigative Magnetic Resonance Imaging
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• v.18 no.2
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• pp.87-106
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• 2014

Purpose : To describe how a robust implementation of a radial 3D gradient-echo sequence with stack-of-stars sampling can be achieved, to review the imaging properties of radial acquisitions, and to share the experience from more than 5000 clinical patient scans. Materials and Methods: A radial stack-of-stars sequence was implemented and installed on 9 clinical MR systems operating at 1.5 and 3 Tesla. Protocols were designed for various applications in which motion artifacts frequently pose a problem with conventional Cartesian techniques. Radial scans were added to routine examinations without selection of specific patient cohorts. Results: Radial acquisitions show significantly lower sensitivity to motion and allow examinations during free breathing. Elimination of breath-holding reduces failure rates for non-compliant patients and enables imaging at higher resolution. Residual artifacts appear as streaks, which are easy to identify and rarely obscure diagnostic information. The improved robustness comes at the expense of longer scan durations, the requirement for fat suppression, and the nonexistence of a time-to-center value. Care needs to be taken during the configuration of receive coils. Conclusion: Routine clinical use of radial stack-of-stars sequences is feasible with current MR systems and may serve as substitute for conventional fat-suppressed T1-weighted protocols in applications where motion is likely to degrade the image quality.

• Industrial Engineering and Management Systems
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• v.7 no.2
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• pp.171-181
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• 2008

Home care, known also as domiciliary care, is part of the community care service that is a responsibility of the local government authorities in the UK as well as many other countries around the world. The aim is to provide the care and support needed to assist people, particularly older people, people with physical or learning disabilities and people who need assistance due to illness to live as independently as possible in their own homes. It is performed primarily by care workers visiting clients' homes where they provide help with daily activities. This paper is concerned with the dispatching of care workers to clients in an efficient manner. The optimized routine for each care worker determines a schedule to achieve the minimum total cost (in terms of distance traveled) without violating the capacity and time window constraints. A collaborative population-based meta-heuristic called Particle Swarm Optimization (PSO) is applied to solve the problem. A particle is defined as a multi-dimensional point in space which represents the corresponding schedule for care workers and their clients. Each dimension of a particle represents a care activity and the corresponding, allocated care worker. The continuous position value of each dimension determines the care worker to be assigned and also the assignment priority. A heuristic assignment scheme is specially designed to transform the continuous position value to the discrete job schedule. This job schedule represents the potential feasible solution to the problem. The Earliest Start Time Priority with Minimum Distance Assignment (ESTPMDA) technique is developed for generating an initial solution which guides the search direction of the particle. Local improvement procedures (LIP), insertion and swap, are embedded in the PSO algorithm in order to further improve the quality of the solution. The proposed methodology is implemented, tested, and compared with existing solutions for some 'real' problem instances.

• Journal of the Korean School Mathematics Society
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• v.22 no.3
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• pp.329-350
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• 2019

Productive struggle is a student's persevering effort to understand mathematical concepts and solve challenging problems that are not easily solved, but the problem can lead to curiosity. Productive struggle is a key component of students' learning mathematics with a conceptual understanding, and supporting it in learning mathematics is one of the most effective mathematics teaching practices. In comparison to research on students' productive struggles, there is little research on preservice mathematics teachers' productive struggles. Thus, this study focused on the productive struggles that preservice mathematics teachers face in solving a non-routine mathematics problem. Polya's four-step problem-solving process was used to analyze the collected data. Examples of preservice teachers' productive struggles were analyzed in terms of each stage of the problem-solving process. The analysis showed that limited prior knowledge of the preservice teachers caused productive struggle in the stages of understanding, planning, and carrying out, and it had a significant influence on the problem-solving process overall. Moreover, preservice teachers' experiences of the pleasure of learning by going through productive struggle in solving problems encouraged them to support the use of productive struggle for effective mathematics learning for students, in the future. Therefore, the study's results are expected to help preservice teachers develop their professional expertise by taking the opportunity to engage in learning mathematics through productive struggle.

• The Mathematical Education
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• v.27 no.1
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• pp.15-23
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• 1988

We are at the onset of a major revolution in education, a revolution unparalleled since the invention of the printing press. The computer will be the instrument of this revolution. Computers and computer application are everywhere these days. Everyone can't avoid the influence of the computer in today's world. The computer is no longer a magical, unfamiliar tool that is used only by researchers or scholars or scientists. The computer helps us do our jobs and even routine tasks more effectively and efficiently. More importantly, it gives us power never before available to solve complex problems. Mathematics instruction in secondary schools is frequently perceived to be more a amendable to the use of computers than are other areas of the school curriculum. This is based on the perception of mathematics as a subject with clearly defined objectives and outcomes that can be reliably measured by devices readily at hand or easily constructed by teachers or researchers. Because of this reason, the first large-scale computerized curriculum projects were in mathematics, and the first educational computer games were mathematics games. And now, the entire mathematics curriculum appears to be the first of the traditional school curriculum areas to be undergoing substantial trasformation because of computers. Recently, many research-Institutes of our country are going to study on computers in orders to use it in mathematics education, but the study is still start ing-step. In order to keep abreast of this trend necessity, and to enhance mathematics teaching/learning which is instructed lecture-based teaching/learning at the present time, this study aims to develop/present practical method of computer-using. This is devided into three methods. 1. Programming teaching/learning method This part is presented the following five types which can teach/learn the mathematical concepts and principle through concise program. (Type 1) Complete a program. (Type 2) Know the given program's content and predict the output. (Type 3) Write a program of the given flow-chart and solve the problem. (Type 4) Make an inference from an error message, find errors and correct them. (Type 5) Investigate complex mathematical fact through program and annotate a program. 2. Problem-solving teaching/learning method solving This part is illustrated how a computer can be used as a tool to help students solve realistic mathematical problems while simultaneously reinforcing their understanding of problem-solving processes. Here, four different problems are presented. For each problem, a four-stage problem-solving model of polya is given: Problem statement, Problem analysis, Computer program, and Looking back/Looking ahead. 3. CAI program teaching/learning method This part is developed/presented courseware of sine theorem section (Mathematics I for high school) in order to avail individualized learning or interactive learning with teacher. (Appendix I, II)

• Korean Journal of Childcare and Education
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• v.9 no.5
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• pp.157-179
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• 2013

The purpose of this study was to examine psychological and behavioral characteristics of parents from low income families and to figure out the influence of these parents' characteristics upon children's problematic behaviors by comparing two-parent families and single-parent families. The subjects in this study were 193 parents who participated in a dream- start program geared toward low-income families. Their psychological and behavioral characteristics were tested, and their children's problem behaviors were investigated. As a result, the children from intact families in the low-income classes showed more problem behaviors when their parents faced heavier parental stress, and they showed less problem behaviors when their parents were more satisfied with their relationship with them. In contrast, the children from single-parent families in the low-income brackets showed less problem behaviors when their parents had better dietary habits and were more satisfied with their daily routine life, and they showed more problem behaviors when their parents were under heavier parental stress. The findings of the study seem to suggest that the development of parental and parent education programs is required to relieve the problem behaviors of children from the low-income classes and improve the parental behavior of their parents, and that a wide variety of assistance should be provided in consideration of the current marital status of parents as well.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.4
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• pp.1-7
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• 2007

As more highways are constructed and more cars are running on them, toll of roadkill steadily increases. To make the problem more serious, roadkill include endangered species. This study compared two sets of roadkill data of selected Korean highways. One set of data were produced, as a routine job of everyday, by the Korea Highway Corporation (KHC), and the other by a team of wildlife researchers for a limited period of time for research purposes. The aims of the comparison were to identify if the species of the animal, location of the roadkill, time, and other information were kept reasonably, especially in the forms provided to the patrols of KHC, to be used for research purposes later. Major findings and suggestions are; 1) KHC patrols are not wildlife professionals, which is understandable, and could not identify some animal species killed on the highways. As they also are not aware of the importance of the accurate data for the wildlife protection, education to promote their awareness is needed. 2) Current form used by the patrols is far from enough to produce good data for research. A new and detailed form needs to be designed and provided to the patrols so that they can keep all the necessary data on roadkills for monitoring and research purposes. If these issues are addressed, the data collected daily by KHC will become good inputs for roadkill researches in Korea.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.451-455
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• 2008

In this paper, we present how we implement the low-level, triangle intersection routine in a massively parallel fashion using n VIDIA's new GPGPU language, CUDA. Triangle intersection often becomes a computational bottleneck in the collision detection problem. Due to the relatively low bandwidth between CPU and GPU, it has been challenging to implement efficient, object-space collision detection between triangle sets. However, thanks to the improved data transmission rates in CUDA architecture, in this paper, we improved the performance of triangle intersection substantially better than the optimized CPU counterpart.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.1
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• pp.65-74
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• 1993

The buckling load of a blade stiffened laminated composite plate having midplane symmetry is maximized for a given total weight. The thicknesses of the layers and the width and height of the stiffener are taken as the design variables. Buckling analysis is carried out using a finite element method. The optimization problem is solved using an IMSL subroutine. Due to the highly nonlinear nature of the optimality equations, several local optimum solutions are found. Various combinations of fiber orientation for the laminate layers and the blade stiffener are investigated to examine their relative efficiency. Out of several cases examined, the best design was produced from the combination of ($0^{\circ}Beam/0^{\circ}/90^{\circ}$)s.

• The Korean Journal of Applied Statistics
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• v.31 no.1
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• pp.97-108
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• 2018

It has been routine practice in regression analysis to check the validity of the assumed model by the use of regression diagnostics tools. Outliers and influential observations often distort the regression output in an undesired manner. Jang and Anderson-Cook (Quality and Reliability Engineering International, 30, 1409-1425, 2014) proposed a graphical method (called a firework plot) so that there could be an exploratory visualization of the trace of the impact of the possible outliers and influential observations on individual regression coefficients and the overall residual sum of the squares measure. This paper further extends a graphical approach to a multi-response surface methodology problem.

• Journal of Chest Surgery
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• v.23 no.1
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• pp.122-127
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• 1990

The management of esophageal carcinoma continues to be a difficult problem with most surgically treated patients under-going extensive operative procedures for palliation only. Although recent advances in preoperative and postoperative care have decreased the operative mortality rate, survival has not changed significantly. Twenty five patients with esophageal carcinoma who were treated with operative intervention at the Department of Thoracic and Cardiovascular Surgery in Kyung Hee University Hospital between January, 1980 and December, 1987 had been evaluated clinical manifestation and operative results. The stamm typed feeding gastrostomy and Celestin tube insertion were performed for the cases of nonresectable esophageal cancer. Also 14 cases with esophagogastrostomy and are case with esophagocologastrostomy were performed for the resectable cases. Two deaths with resectable cases occurred within 30days of operation, a hospital death rate of 8 per cent. There were significant differences in the survival rate between T.N.M. staging I, II, and III, IV group after the resection of the esophageal cancer. The former group revealed higher one year survival rate than the later group. [p< 0.05]. In conclusion, the clinical manifestations and operative results were similar to the western ones and the postoperative survival rate was very poor. So, the earlier the operation of the esophageal cancer was done, the better result will be achieved. To defect the early esophageal cancer; routine esophagoscopy should be recommended.