• Journal of the Korean School Mathematics Society
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• v.17 no.4
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• pp.657-677
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• 2014

The present qualitative case study explored the ways in which three middle school students constructed and refined their mathematical models and modeling processes, and factors that had influenced such refinement. The results suggest that students' modeling processes are non-sequential in that the participant students reformulated their initial problem from the real-world problem situation and revised the model when they could not get a satisfactory solution or the acquired solution did not make sense. Moreover, the students' model refinement processes were affected by the following four elements: the types of real-word problem situations, students' metacognitive thinking, communications between teachers and peers, and the role of teachers.

• Korean Journal of Adult Nursing
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• v.19 no.5
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• pp.56-69
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• 2007

Purpose: This study aimed to explore the discourses and the patterns of problem solving behaviors among the nurse managers. The focus of the study was the difficult situations in caring with patients and their families. Methods: Field study was performed at a for-profit hospital from March, 2004 to March, 2007. The participants of the study were 5 head nurses and 2 nurses in charge. The data were collected with iterative interviews and participant-observations. For the analysis of the data, taxonomy and critical discourse analyzing were applied. Results: The nurse mangers who showed wholistic patterns of behavior took the role of a broker among the client system, professional nursing system, medical system, and other allied health system. The nurse managers whose approach was profession-centered took the role of protector of nursing system. The nurse manager who practiced nurse-oriented pattern of behavior tried not to have harm against other members of health system. The experiences of nurse managers were effected from the discourses of patriarchal and market mechanism. Conclusion: The situation that provoke conflict between clients and nurses become more common with the changes to the health care system and to society. Nurse managers take the role of these conflict problems. The successful solving of conflict in a nursing care setting promotes the quality of care and satisfaction of clients. Programs for enhancing nurse's problem solving competency should anchored be in their practices.

• Journal of the Korean Operations Research and Management Science Society
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• v.27 no.4
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• pp.185-205
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• 2002

In this study, we consider infinite supply of raw materials and backlogged demands as given two boundary conditions. And we need not make any specific assumptions about the inter-arrival of external demand and service time distributions. Under these situations, the ultimate objective of this study is to prove the variability propagation principle in a pull serial line and is to measure it in terms of the first two moments of the inter-departure process subject to number of cards in each cell. Two preparations are required to achieve this objective : The one is to derive a true lower bound of variance of the inter-departure process. The other is to establish a constrained discrete minimax problem for the no backorder (backlogging) probabilities in each cell. We may get some fundamental results necessary to a completion for the proof through the necessary and sufficient conditions for existence of optimal solution of a constrained discrete minimax problem and the implicit function theorem. finally, we propose a numeric model to measure the variability propagation principle. Numeric examples show the validity and applicability of our study.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.363-366
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• 2016

In this paper, we propose a method for detecting pedestrian, problem-solving situations that occur in a cross. When a pedestrian crossing and other, there occurs a problem of detecting the other pedestrians for detecting a specific pedestrian in the image. The proposed method for solving the problem is as follows. First, select a specific pedestrian detected by bounding box, and extracts the area as a template. Detecting a pedestrian from the image using the HOG, and designated as a candidate region. The final choice of the pedestrian detected by comparison with a candidate pedestrian with the specific pedestrian extracted for template. In comparison, using the Template matching, Histogram comparison and LBP.

• Journal of Communications and Networks
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• v.13 no.4
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• pp.360-366
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• 2011

In this paper, we investigate the problem of power allocation in a heterogeneous network that is composed of a pair of cognitive users (CUs) and an infrastructure-based primary network. Since CUs have only limited effective spectrum-sensing ability and primary users (PUs) are not active all the time in all locations and licensed bands, we set up a new multi-area model to characterize the heterogeneous network. A novel combined interference-avoidance policy corresponding to different PU-appearance situations is introduced to protect the primary network from unacceptable disturbance and to increase the spectrum secondary-reuse efficiency. We use dual decomposition to transform the original power allocation problem into a two-layer optimization problem. We propose a low-complexity joint power-optimizing method to maximize the transmission rate between CUs, taking into account both the individual power-transmission constraints and the combined interference power constraint of the PUs. Numerical results show that for various values of the system parameters, the proposed joint optimization method with combined PU protection is significantly better than the opportunistic spectrum access mode and other heuristic approaches.

• Proceedings of the Korea Contents Association Conference
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• 2018.05a
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• pp.167-168
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• 2018

The importance of business problem-solving creativity (BPSC) becomes crucial much more as competitive situations go on in the market. However, how to assess the BPSC remains an unsolved research issue yet in the literature. In this sense, this study proposes an exploratory analysis of the BPSC from the view of neuro-science experiments called fNIRS. The fNIRS represents a functional near-infrared spectroscopy, a new type of neuro-science research paradigm. This study proposes an exploratory level of how to conduct the fNIRS-based experiments to analyze the BPSC.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.2
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• pp.248-257
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• 2014

As observed in the recent war, suppression of enemy air defense operation is one of the major tactics, simultaneously conducted with high payoff target. Specifically, our air defense operation should be properly constructed, since the operating environment of our forces mostly consists with mountainous terrain, which makes detections of the enemy difficult. The effective arrangements of low altitude air defense radars can be suggested as a way of improving the detection capability of our forces. In this paper, we consider the location problem of low altitude air defense radar, and formulate it as an Integer Programming. Specifically, we surveyed the previous researches on facility location problems and applied two particularly relevant models(MCLP, MEXCLP) to our problem. The terrain factor was represented as demand points in the models. We verified the optimal radar locations for operational situations through simulation model which depicts simple battle field. In the simulation model, the performance of optimal radar locations are measured by the enemy detection rate. With a series of experiments, we may conclude that when locating low altitude air defense radars, it is important to consider the detection probability of radar. We expect that this finding may be helpful to make a more effective air defense plan.

• Journal of Korean Academic Society of Home Health Care Nursing
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• v.25 no.3
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• pp.215-223
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• 2018

Purpose: The purpose of this study was to investigate effects of nurse managers' conflict management styles on nurses' levels of leader trust and organizational commitment. Methods: For this study, a descriptive survey design was used. The participants were 165 nurses who had worked more than 1 year in a university hospital. Data were collected from September 1 to September 10, 2016, using a self-report questionnaire. The collected data were analyzed using descriptive statistics, t-tests, ANOVA, Scheffe's tests, Pearson's correlation coefficients, and multiple regression analysis. Results: Among the nurse managers' conflict management styles, the problem-solving style was positively correlated with both leader trust and organizational commitment. Concession-avoiding and control-leading styles were negatively correlated with both variables. Furthermore, the problem-solving style was found to have significant influence on both leader trust and organizational commitment. Conclusion: In order to more actively cope with conflict situations occurring in the nursing work environment, nursing managers need to exhibit more effective attitudes of conflict management. This study suggests that the problem-solving style is a desirable conflict management style in terms of increasing leader trust and organizational commitment.

• Journal of IKEEE
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• v.25 no.4
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• pp.650-663
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• 2021

Subsurface topology estimation is an important factor in the geophysical survey. Electrical impedance tomography is one of the popular methods used for subsurface imaging. The EIT inverse problem is highly nonlinear and ill-posed; therefore, reconstructed conductivity distribution suffers from low spatial resolution. The subsurface region can be approximated as piece-wise separate regions with constant conductivity in each region; therefore, the conductivity estimation problem is transformed to estimate the shape and location of the layer boundary interface. Each layer interface boundary is treated as an open boundary that is described using front points. The subsurface domain contains multi-layers with very complex configurations, and, in such situations, conventional methods such as the modified Newton Raphson method fail to provide the desired solution. Therefore, in this work, we have implemented a 7-layer artificial neural network (ANN) as an inverse problem algorithm to estimate the front points that describe the multi-layer interface boundaries. An ANN model consisting of input, output, and five fully connected hidden layers are trained for interlayer boundary reconstruction using training data that consists of pairs of voltage measurements of the subsurface domain with three-layer configuration and the corresponding front points of interface boundaries. The results from the proposed ANN model are compared with the gravitational search algorithm (GSA) for interlayer boundary estimation, and the results show that ANN is successful in estimating the layer boundaries with good accuracy.

• Steel and Composite Structures
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• v.43 no.5
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• pp.661-672
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• 2022

The solution of contact problems is extremely important as we encounter many situations involving such problems in our daily lives. One of the most important parameters effective in solving contact problems is the materials of the parts in contact. While it is relatively easy to solve the contact mechanics of the systems created with traditional materials with a homogeneous microstructure and mechanical distribution, it may be more difficult to solve the contact problem of new generation materials that do not show a homogeneous distribution. As a result of this situation, it is seen that studies on contact problems of materials that do not exhibit such a homogeneous internal structure and mechanical properties are extremely limited in the literature. In this context, in this study, analytical and numerical analyzes of a contact problem created using functionally graded materials were carried out and the results were evaluated mutually. It has been decided that the contact areas and contact pressures acquired from numerical method are reasonably appropriate with the results obtained from the analytical method.