• Journal of Korean Institute of Industrial Engineers
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• v.34 no.1
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• pp.32-41
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• 2008

This paper studies a joint EOQ and EPQ model in which a stationary demand can be satisfied by recycled products as well as newly purchased products. The model assumes that a fixed quantity of the used products are collected from customers and later recovered for reuse. The recovered products are regarded as perfectly new ones. We also assume that the number of orders for newly purchasing items and the number of recovery setups in a cycle can be mutually independent integers. Under these assumptions, we develop an optimization model obtaining the economic order quantity for newly procured products, the optimal lot size for the recovery process, and the sequence of the orders and the setups, simultaneously. And then a simple solution procedure to find a local optimal control parameter set is proposed. To validate the model and the solution procedure, finally, some computational experiments are presented.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.786-789
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• 2002

A recurrent artificial neural network (ANN) model is developed to simulate hydrocarbon recovery process at petroleum-contaminated site. The groundwater extraction rate, vacuum pressure, and saturation hydraulic conductivity are selected as the input variables, while the cumulative hydrocarbon recovery volume is considered as the output variable. The experimental data fer establishing the ANN model are from implementation of a multiphase flow model for dual phase remediation process under different input variable conditions. The complex nonlinear and dynamic relationship between input and output data sets are then identified through the developed ANN model. Reasonable agreements between modeling results and experimental data are observed, which reveals high effectiveness and efficiency of the neural network approach in modeling complex hydrocarbon recovery behavior.

• Korean Journal of Agricultural Science
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• v.23 no.2
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• pp.233-241
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• 1996

The mechanical properties of biological materials depend on numerous factors. The majority of these relationships are still unknown today, especially with regard to their quantitative characteristics. The reason is that biological materials constitute biomechanical systems of very complex construction, whose behavior cannot be characterized by simple physical constants, as for example can that of engineering materials. The objectives of this investigation were to determine the compression creep and recovery properties of rice stalks at various levels of applied load The compression creep and recovery behavior of the rice stalk could be predicted precisely by rheological model which approached closely to the measured values. But the coefficients of the Burgers recovery model were different from those of the creep model. The Steady state creep behavior occurred at the higher level of force and the logarithmic creep behavior occurred at the lower level of force. The mechanical model being expected the creep behavior in relation with the level of applied load, which was well explained that the rice stalk might be visco-elastic material.

• Industrial Engineering and Management Systems
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• v.14 no.2
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• pp.159-174
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• 2015

Remanufacturing used, end-of-life products is a complex problem involving multiple types of products that may share common parts. Recovery targets assigned by market demand and environmental legislation add more difficulty to the problem. Manufacturers now need to achieve specified take-back and recovery rates while fulfilling demands for remanufactured products. To assists in the demand- and legislation-driven remanufacturing of a family of products (i.e., multiple products that share common parts), this paper introduces a bi-objective mixed integer linear programming (MILP) model for optimizing remanufacturing. The model identifies optimal remanufacturing plans for a product family, whereby, the remanufacturer can achieve demand and recovery targets more profitably and in an environmentally-friendly manner. The model can also be used to quantify and justify the economic and environmental benefits of a product family from a remanufacturing perspective. A case study is presented for remanufacturing an alternatorfamily of products.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.713-723
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• 2023

Climate change is significantly affecting coastal areas, and its impacts are expected to intensify. Recent studies on climate change adaptation and risk assessment in coastal regions increasingly integrate the concepts of recovery resilience and vulnerability. The aim of this study is to develop a measurement model for coastal hazard recovery resilience in the context of climate change adaptation. Before constructing the measurement model, a comprehensive literature review was conducted on coastal hazard recovery resilience, establishing a conceptual framework that included operational definitions for vulnerability and recovery resilience, along with several feedback mechanisms. The measurement model for coastal hazard recovery resilience comprised four metrics (MRV, LRV, RTSPV, and ND) and a Coastal Resilience Index (CRI). The developed indices were applied to domestic coastal erosion cases, and regional analyses were performed based on the index grades. The results revealed that the four recovery resilience metrics provided insights into the diverse characteristics of coastal erosion recovery resilience at each location. Mapping the composite indices of coastal resilience indicated that the areas along the East Sea exhibited relatively lower coastal erosion recovery resilience than the West and South Sea regions. The developed recovery resilience measurement model can serve as a tool for discussions on post-adaptation strategies and is applicable for determining policy priorities among different vulnerable regional groups.

• Journal of Information Technology Services
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• v.15 no.1
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• pp.269-287
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• 2016

In general, service failure occurs inevitably and the customers who experienced the greater dissatisfaction have the higher expectations of service recovery. However, most of the previous studies have focused on the evaluation and risk factors of pre-service quality. Thus, this study is contrary to the numerous previous studies and focus on the effectiveness of mobile application advertisement users' perceived perception on service recovery after service fails. A research model presented in this study is based on the Equity Theory and deeply evaluated the effectiveness of Distributive Justice, Interactional Justice, and Authenticity Relevance on Service Recovery. The survey of this study was conducted among 286 users who have experienced a services recovery of mobile application advertising. As a result, among all the factors of users of mobile application advertising, Distributive Justice, Interactive Justice, and Relevance have a positive impact to Satisfaction. In addition, Distributive Justice, Authenticity and Satisfaction also have a positive impact to Trust. Ultimately, Satisfaction and Trust have a positive impact to Service Recovery. The results of this study are expected as a reference for presenting a new business model for mobile application advertising industry, reducing business risk and enriching the related researches.

• Journal of the Korean Society of Clothing and Textiles
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• v.35 no.7
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• pp.841-855
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• 2011

This study examines the structured model of building fashion customer loyalty by service recovery and scrutinizes the effect of explanations on perceived justice and the proposed model. The data of a total of 300 women were collected through an online survey. Employing structural equation modeling, this study demonstrated that both distributive and interactional justice had a positive impact on customers' satisfaction with service encounter that subsequently led to overall satisfaction with the brand. Overall satisfaction influenced the attitudinal loyalty of customers that induced their behavioral loyalty. To examine the effect of explanations on perceived justice and the process of building fashion customer loyalty by service recovery, t-test and multi-group SEM were employed. The result displayed that the group who received explanations after service failure perceived higher level of justice than the one who did not. There was a significant difference between two groups on the direct path from interactional justice to overall satisfaction with the brand. This study clarifies how perceived justice influences fashion customer loyalty mediating by satisfaction in and confirms the critical role of explanations in service recovery context. By implying the understanding of the important role of explanations in service recovery context, this study provides fashion marketers with insight for delivering more successful service recovery strategies that enhance customer loyalty.

• Journal of the Korean Operations Research and Management Science Society
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• v.29 no.4
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• pp.95-116
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• 2004

This study will attempt to build an integrated model of the customer satisfaction process with service encounter in a comprehensive point of view including the expectancy-disconfirmation theory, justice theory, and attribution theory. In addition, this study will attempt to examine the influence of service failure-related variables and service recovery-related variables on customer satisfaction in the airline firms' service failure and recovery situation. The results showed that the higher the controllability and severity of the failure, the more positive influence on expectancy of recovery and more negative influence on the recovery satisfaction increased. They also showed that the higher procedural recovery efforts and distributive/interactional recovery efforts, the more positive influence on perceived recovery performance and recovery satisfaction also increased. It was found that the recovery satisfaction with service encounter depended on the extent to which the customer's perception of recovery efforts confirmed the expectancy of recovery. Also it was found that perceived recovery performance has an effect on recovery satisfaction through the mediation of recovery disconfirmation indirectly as well as directly.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.1
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• pp.64-70
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• 2015

Organic Rankine cycle (ORC) is an useful cycle for power generation system with low temperature heat sources ($80{\sim}400^{\circ}C$). Since the boiling point of operating fluid is low, the system is used to recover the low temperature heat source of waste heat energy. In this study, a ORC with R134a is applied to recover the waste energy of condenser of coal fired power plant. A system model is developed via Thermolib$^{(R)}$ under Simulink/MATLAB environment. The model is composed of a refrigerant heat exchanger for heat recovery from coal fired condenser, a drum, turbine, heat exchanger for ORC heat rejection, storage tank, water recirculation pump and water drip pump. System analysis parameters were heat recovery capacity, type of refrigerants, and types of turbines. The simulation model is used to analyze the heat recovery capacity of ORC power system. As a result, increasing the overall heat transfer coefficient to become the largest of turbine power is the most economical.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.12
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• pp.5116-5134
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• 2015

In this paper, due to the network security defense is mainly static defense, a dynamic classification network security defense strategy model is proposed by analyzing the security situation of complex computer network. According to the network security impact parameters, eight security elements and classification standard are obtained. At the same time, the dynamic classification algorithm based on fuzzy theory is also presented. The experimental analysis results show that the proposed model and algorithm are feasible and effective. The model is a good way to solve a safety problem that the static defense cannot cope with tactics and lack of dynamic change.