• Nuclear Engineering and Technology
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• v.52 no.8
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• pp.1807-1816
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• 2020

In this work, a Gaussian Process (Kriging) approach is proposed to provide efficient dose mapping for complex radiation fields using limited number of responses. Given a few response measurements (or simulation data points), the proposed approach can help the analyst in completing a map of the radiation dose field with a 95% confidence interval, efficiently. Two case studies are used to validate the proposed approach. The First case study is based on experimental dose measurements to build the dose map in a radiation field induced by a D-D neutron generator. The second, is a simulation case study where the proposed approach is used to mimic Monte Carlo dose predictions in the radiation field using a limited number of MCNP simulations. Given the low computational cost of constructing Gaussian Process (GP) models, results indicate that the GP model can reasonably map the dose in the radiation field given a limited number of data measurements. Both case studies are performed on the nuclear engineering radiation laboratories at the University of Sharjah.

• Communications for Statistical Applications and Methods
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• v.20 no.6
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• pp.455-466
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• 2013

In nested case-control studies, the most common way to make inference under a proportional hazards model is the conditional logistic approach of Thomas (1977). Inclusion probability methods are more efficient than the conditional logistic approach of Thomas; however, the epidemiology research community has not accepted the methods as a replacement of the Thomas' method. This paper promotes the inverse probability weighting method originally proposed by Samuelsen (1997) in combination with an approximate jackknife standard error that can be easily computed using existing software. Simulation studies demonstrate that this approach yields valid type 1 errors and greater powers than the conditional logistic approach in nested case-control designs across various sample sizes and magnitudes of the hazard ratios. A generalization of the method is also made to incorporate additional matching and the stratified Cox model. The proposed method is illustrated with data from a cohort of children with Wilm's tumor to study the association between histological signatures and relapses.

• Korean Journal of Social Welfare
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• v.54
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• pp.273-294
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• 2003

The outcome of study has shown that team approach in case management in the community welfare center has shown a fair amount of effectiveness in increasing the quality of life for the elderly. 30 elderly people who had complex difficulties in life were selected and given case management for a 6 month period. The student volunteers supervised by a case manager visited the clients once a week and arranged a series of community resources following assessment of the clients' needs. A group of professionals active in the community was invited for supervision. Compared to the clients in the comparison group, those clients who case management showed the increase in the quality of life and life satisfaction scale. The results of the study suggest that face-to-face service for the elderly is one important factor for successful case management intervention. Also, a team approach in case management utilizing professionals and volunteers can be useful for the case manager in the community welfare center who is overwhelmed with too many case loads.

• East Asian Journal of Business Economics (EAJBE)
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• v.9 no.4
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• pp.93-102
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• 2021

Purpose - Among the various pricing approaches used to set fares for express trains, this study explores a method of utilizing a customer-based pricing approach. The purpose of this study is to figure out how to apply the customer-based pricing approach to fares of new railway services using express trains. Research design, data, and methodology - This study was conducted through a literature review and case studies. In the literature review, we examined three approaches, focusing on the customer-based pricing approach and its application. In the case studies, we show how a customer-based pricing approach can be applied to determining the fares for railway services. Result - Some studies have used a customer-based pricing approach to set railway service rates, adapting the concepts of customer-based pricing such as demand, elasticity, value and willingness to pay. When setting fares of new railway services, it is recommended to use the customer-based approach in conjunction with other pricing approaches. Conclusion - This study demonstrates that a customer-based pricing approach is a promising tool in making decisions on railway fares. By applying a customer-based pricing approach to fares for new railway services using express trains, railway operators can utilize new service rates and increase the profitability of the railway business.

• The Korean Journal of Ecology
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• v.26 no.5
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• pp.289-296
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• 2003

The ecological process-based approach provides a detailed assessment of belowground compartment as one of the major compartment of carbon balance. Carbon net balance (NEP: net ecosystem production) in forest ecosystems by ecological process-based approach is determined by the balance between net primary production (NPP) of vegetation and heterotrophic respiration (HR) of soil (NEP=NPP-HR). Respiration due to soil heterotrophs is the difference between total soil respiration (SR) and root respiration (RR) (HR=SR-RR, NEP=NPP-(SR-RR)). If NEP is positive, it is a sink of carbon. This study assessed the forest carbon balance by ecological process-based approach included belowground compartment intensively. The case study in the Takayama Station, cool-temperate deciduous broad-leaved forest was reported. From the result, NEP was estimated approximately 1.2 t C $ha^{-1} yr^{-1}$ in 1996. Therefore, the study area as a whole was estimated to act as a sink of carbon. According to flux tower result, the net uptake rate of carbon was 1.1 t C $ha^{-1} yr^{-1}$.

• Proceedings of the Korea Society for Simulation Conference
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• 2003.11a
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• pp.87-93
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• 2003

This paper reviews existing message-filtering schemes and presents a quantization-based message-filtering approach which reduces state update transmission and message traffic requirement. For a realization of the approach we develop a DEVS-based integrator which provides behavior and characteristic of the quantization-based approach. We take a spaceship and space traveling system as a case study to evaluate performance of the quantization-based approach. The approach is validated by DEVSJAVA simulations of the case study. The comparison of message traffic requirement between DTSS (Discrete Time System Specification)-based and DEVS-based systems apparently shows system performance improvement through the quantization-based approach.

• Industrial Engineering and Management Systems
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• v.13 no.4
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• pp.369-382
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• 2014

This paper introduces a new multi-product multi-period multi-objective aggregate production planning problem. The proposed problem is modeled using multi-objective mixed-integer mathematical programming. Three objective functions, including minimizing total cost, maximizing customer services level, and maximizing the quality of end-product, are considered, simultaneously. Several constraints such as quantity of production, available time, work force levels, inventory levels, backordering levels, machine capacity, warehouse space and available budget are also considered. Some parameters of the proposed model are assumed to be qualitative and modeled using fuzzy sets. Then, a fuzzy goal programming approach is proposed to solve the model. The proposed approach is applied on a real-world industrial case study of a color and resin production company called Teiph-Saipa. The approach is coded using LINGO software. The efficacy and applicability of the proposed approach are illustrated in the case study. The results of proposed approach are compared with those of the existing experimental methods used in the company. The relative dominance of the proposed approach is revealed in comparison with the experimental method. Finally, a data dictionary, including the way of gathering data for running the model, is proposed in order to facilitate the re-implementation of the model for future development and case studies.

• Asia pacific journal of information systems
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• v.13 no.1
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• pp.103-118
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• 2003

Software project planning is usually represented by a project activity network that is composed of stages of tasks to be done and precedence restrictions among them. The project network is very complex and its construction requires a vast amount of field knowledge and experience. So this study proposes a case-based reasoning approach that can generate the project network automatically based on the past cases and modification knowledge. For the case indexing, we have adopted 17 factors, each with a few alternative values. A special structure of this problem is that the modification effort can be identified by each factor independently. Thus it is manageable to identify 85 primitive modification actions(add and delete activities) and estimate its modification efforts in advance. A specific case requires a combination of primitive modifications. Based on the modification effort knowledge, we have adopted the Least Modification approach as a metric of similarity between a new project and past cases. Using the Least Modification approach and modification knowledge base, we can automatically generate the project network. To validate the performance of Least Modification approach, we have compared its performance with an ordinary minimal distance approach for 21 test cases. The experiment showed that the Least Modification approach could reduce the modification effort significantly.

• Journal of The Korean Association For Science Education
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• v.32 no.8
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• pp.1356-1366
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• 2012

As the recent demand for human resources in science, technology, engineering, and mathematics (STEM), the development of professional STEM teacher is called worldwide. It is becoming a critical need in teacher education in order to educate student teachers, and prepare pre-service and beginning teachers for high quality of teaching competency. To promote the competency for $21^{st}$ century STEM teachers, the epistemology of technological pedagogical content knowledge (TPACK) is currently considered as the essential qualities of knowledge for highly qualified teachers. The aim of this study is explore the effect of case-based learning approach on TPACK competency of pre-service STEM teachers. In order to develop the pre-service teachers' competency regarding effective integration of technologies into teaching specific content areas, a series of innovative case study teaching in science and mathematics was presented to 43 participants of pre-service physics, chemistry, biology, mathematics, and computer teachers during a course of information and communication technology (ICT) in Education at Khon Kaen University, Thailand. After finishing a case presentation, the pre-service teachers were encouraged into a forum of critical open discussion by considering the potential impact of the case and the TPACK framework. They were investigated instructional design competency of using ICT tools into student learning process and their personal beliefs about ICT in educational process both before and after. The participant's reactions and learning was evaluated by using a self-reported questionnaire and an implementation log of content-specific learning process design, respectively. Results showed a change of their beliefs and the transformation of their TPACK competency in STEM teaching. In an effort to better serve the needs of high quality STEM teachers, the results of this study illustrated that the competency of TPACK could be particularly considered as a core attributes for future STEM teachers. By the way, case-based learning approach can play an effective part in preparing and professing the TPACK competency for STEM teachers.

• Computers and Concrete
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• v.20 no.6
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• pp.645-654
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• 2017

Continuing from previous studies of sustainable concrete containing environmentally friendly materials and existing modeling approach to predicting concrete properties, this study developed an estimation methodology to predicting the strength of sustainable concrete using an advanced case-based reasoning approach. It was conducted in two steps: (i) establishment of a case database and (ii) development of an advanced case-based reasoning model. Through the experimental studies, a total of 144 observations for concrete compressive strength and tensile strength were established to develop the estimation model. As a result, the prediction accuracy of the A-CBR model (i.e., 95.214% for compressive strength and 92.448% for tensile strength) performed superior to other conventional methodologies (e.g., basic case-based reasoning and artificial neural network models). The developed methodology provides an alternative approach in predicting concrete properties and could be further extended to the future research area in durability of sustainable concrete.