• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.08a
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• pp.368-377
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• 2004

A mathematical model was developed for the prediction of the average temperature and RDT(RM Delivery temperature) in a roughing mill. The model consisted of three parts as follows (1) The intermediate numerical model calculated the deformation and heat transfer phenomena in the rolling: region by steady state FEM and the heat transfer phenomena in the interpass region by unsteady state FEM (2) The Off-line prediction model was derived from non-linear regression analysis based on the results of intermediate numerical model considering the various rolling conditions, (3) Using the heat flux in rolling region, temperature profile along thickness direction was calculated. For validation of the presented model, the rolling force per pass and RDT measued in on-line process was compared with those of model and the results showed close agreement with the existing data. In order to demonstrate the effectiveness of the proposed model, the various rolling conditions was tested.

• Journal of Communications and Networks
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• v.13 no.5
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• pp.536-543
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• 2011

The heterogeneous postal delivery model assumes that each intermediate node in the multicasting tree incurs a constant switching time for each message that is sent. We have proposed a new model where we assume a more generalized switching time at intermediate nodes. In our model, a child node v of a parent u has a switching delay vector, where the ith element of the vector indicates the switching delay incurred by u for sending the message to v after sending the message to i-1 other children of u. Given a multicast tree and switching delay vectors at each non-root node 5 in the tree, we provide an O(n$^{\frac{5}{2}}$) optimal algorithm that will decide the order in which the internal (non-leaf) nodes have to send the multicast message to its children in order to minimize the maximum end-to-end delay due to multicasting. We also show an important lower bound result that optimal multicast switching delay problem is as hard as min-max matching problem on weighted bipartite graphs and hence O(n$^{\frac{5}{2}}$) running time is tight.

• Archives of Plastic Surgery
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• v.48 no.4
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• pp.448-456
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• 2021

Background Locoregional stem cell delivery is very important for increasing the efficiency of cell therapy. Amnisite BA (Amnisite) is a freeze-dried amniotic membrane harvested from bovine placenta. The objective of this study was to investigate the retention of cells of the stromal vascular fraction (SVF) on Amnisite and to determine the effects of cell-loaded Amnisite in a porcine radiation-induced chronic wound model. Methods Initially, experiments were conducted to find the most suitable hydration and incubation conditions for the attachment of SVF cells extracted from pig fat to Amnisite. Before seeding, SVFs were labeled with PKH67. The SVF cell-loaded Amnisite (group S), Amnisite only (group A), and polyurethane foam (group C) were applied to treat radiation-induced chronic wounds in a porcine model. Biopsy was performed at 10, 14, and 21 days post-operation for histological analysis. Results Retaining the SVF on Amnisite required 30 minutes for hydration and 1 hour for incubation. A PKH67 fluorescence study showed that Amnisite successfully delivered the SVF to the wounds. In histological analysis, group S showed increased re-epithelialization and revascularization with decreased inflammation at 10 days post-operation. Conclusions SVFs had acceptable adherence on hydrated Amnisite, with successful cell delivery to a radiation-induced chronic wound model.

• Journal of Korean Institute of Industrial Engineers
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• v.30 no.4
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• pp.346-354
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• 2004

Most industrial logistic systems have focused on carrying products from manufacturers or distribution centers to customers. In recent years, they are faced with the problem of integrating reverse flows into their transportation systems. In this paper, we address the vehicle routing problems with mixed delivery and pick-up(VRPMDP). Mixed operation of delivery and pick-up during a vehicle tour requires rearrangement of the goods on board. The VRPMDP considers the reshuffling time of goods at customers, hard time windows, and split operation of delivery and pick-up. We construct a mixed integer mathematical model and propose a new genetic algorithm named GAMP for VRPMDP. Computational experiments on various types of test problems are performed to evaluate GAMP against the modified Dethloff's algorithm. The results show that GAMP reduces the total vehicle operation time by 5.9% on average, but takes about six times longer computation time.

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1597-1608
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• 2016

Recently, a number of solutions were proposed to address the challenges and issues of vehicular networks. Vehicular Cloud Computing (VCC) is one of the solutions. The vehicular cloud computing is a new hybrid technology that has a remarkable impact on traffic management and road safety by instantly using vehicular resources. In this paper, we study an important vehicular cloud service, content-based delivery, that allows future vehicular cloud applications to store, share and search data totally within the cloud. We design a VCC-based system architecture for efficient sharing of vehicular contents, and propose a Hierarchical Hybrid Content Delivery scheme using Bloom Filter (H2CDBF) for efficient vehicular content delivery in Vehicular Ad-hoc Networks (VANETs). The performance of the proposed H2CDBF is evaluated through an analytical model, and is compared to the proactive content discovery scheme, Bloom-Filter Routing (BFR).

• Asia Marketing Journal
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• v.16 no.3
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• pp.1-22
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• 2014

In this paper, we posit that time-related effects (i.e., the importance of saving time) on patronage preference for shopping online will be moderated by consumer characteristics. To explore these moderating effects, we empirically examine the moderating roles of consumer characteristics on the respective effects of shopping-time-saved and delivery on online purchase preference. On the basis of analyses performed on data gleaned from an Internet-based survey, this study demonstrate that time effects related to both shopping-time-saved and delivery on online purchase preference are more pronounced for consumers who are male, young, and more starved for time. In addition, the effect of delivery time on online patronage preference is amplified by disposable income, but attenuated by online shopping experience. Through our analyses, we also find that Japanese consumers value delivery time to a greater degree than Chinese and American consumers do.

• Korean Journal of Social Welfare
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• v.57 no.4
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• pp.225-251
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• 2005

This study examines the changing paradigm of family welfare policy and tries to find an appropriate model for the delivery system of family welfare service. First, the study reviews the contexts of family policy in new paradigm, and traces the changing process of family welfare-related administration from the ministry of human and health to the ministry of family and gender equality. Second, the study examines the principles of the delivery system for family welfare service to pursue the advancement of family policy. In conclusion, it proposes an alternative model for the successful settlement into community of family welfare delivery system, and a desirable position and role of family support center. The principles of the delivery system of family welfare service is fundamentally to make family policy come realistic, such as strengthening family stability through the harmonic reconciliation of work and family, preventing any forms of families from social safety net, and securing happy lives. Comprehensiveness, continuity, effectiveness, and accessibility of the system are also needed. In particular, family support center, recently very controversial, could be better as a representative council of networking various kinds of community organizations in the fields of family welfare enhancement, rather than organization of direct service provision, such as family counselling, education and therapy. Finally, an alternative model of delivery system for family welfare service is presented.

• The Journal of the Korea Contents Association
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• v.13 no.8
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• pp.314-323
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• 2013

This study analyzed the relationship between the level of hospital caseloads and length of stay for the delivery patients. The differences of hospital caseloads were measured by the Internal Herfindahl Index, which measured the concentration of delivery patient in a hospital. And the structure variables of hospitals such as the number of bed, the number of treatment, and the number of doctors and nurses per 100 beds were included as control variables. And average length of stay of delivery patients was used as the dependent variable. Concentration status of delivery patients was measured in two models: (1) first model represents the concentration level of delivery patient in all hospital patients, (2) second model represents the concentration level of delivery patient in all obstetrics and gynecology patients. In regression analysis, patient concentration index was not statistically significant in explaining the variation of average length of stay in two models. But the number of delivery patients and number of beds were statistically significant. The number of delivery patient variable showed negative regression coefficient with average length of stay and the number of beds showed positive coefficient with average length of stay. This study result indicated that the volume of delivery patients in a hospital will play a significant role in reducing the length of stay of delivery patients. Patient volume could contribute in improving the efficiency of patient care in a hospital.

• The Korean Journal of Franchise Management
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• v.9 no.1
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• pp.27-39
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• 2018

Purpose - Recently, the mobile application field has been receiving astronomical attention from the past few years due to the growing number of mobile app downloads and withal due to the revenues being engendered. Especially delivery apps by mobile service market is experiencing rapid growth and competition is intensifying. Therefore, delivery apps' choice attributes has become important as a strategy for survival of franchise firms. Based on previous studies, this research proposed the theoretical framework about the structural relationships among customer satisfaction, trust and revisit intention on delivery apps' choice attributes. Research design, data, and methodology - This study examines the structural relationship between choice attributes of using the delivery app, satisfaction, trust, and revisit intention. More specifically, this study has been examined from the perspective of Generation Y who is enjoying electronic commerce and shopping with mobile phone. In this model, choice attributes of delivery app consists of three sub-dimensions such as service quality, system quality, interaction quality. So as to test the purposes of this study, research model and hypotheses were developed. After excluding 24 invalid respondent questionnaires, 201 valid questionnaires were coded and analyzed using frequency, confirmatory factor analysis, correlations analysis, and structural equation modeling with SPSS 21 and SmartPLS 3.0. Result - The results of the study are as follows. First, service quality and interaction quality had positive effects on satisfaction, and interaction quality had positive effects on trust, but system quality did not have a significant effect on both satisfaction and trust. Second, satisfaction had positive effects on both trust and revisit intention. Third, trust had positive effects on revisit intention. Conclusions - The implications of this study are following as: From the theoretical perspective, this study confirms the effect of delivery apps' choice attributes on satisfaction, trust, and revisit intention. In addition, it is significant that we examined the influence of choice attributes of delivery apps on their attitudes and behaviors of Generation Y familiar with mobile environment. Through this study, we hypothesized that the attributes of service quality and interaction quality of delivery apps have a significant effect on customer satisfaction, and this can be expected to provide meaningful implications for the development of franchise restaurant industry. To encourage continuous repurchase through customer satisfaction, franchise companies need to establish various strategic alliances with delivery app companies and new growth engines by providing diverse and high-quality services to customers in the smart age.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.4
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• pp.1527-1552
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• 2018

The rapidly-evolving demand of applications using wireless sensor networks in several areas such as building and industrial automation or smart cities, among other, makes it necessary to determine and provide QoS support mechanisms which can satisfy the requirements of applications. In this paper we propose a mechanism that establishes different QoS levels, based on Publish/Subscribe model for wireless networks to meet application requirements, to provide reliable delivery of packet and timeliness. The first level delivers packets in a best effort way. The second one intends to provide reliable packet delivery with a novel approach for Retransmission Timeout (RTO) calculation, which adjusts the RTO depending on the subscriber Packet Delivery Ratio (PDR). The third one provides the same reliable packet delivery as the second one, but in addition, it provides data aggregation trying to be efficient in terms of energy consumption and the use of network bandwidth. The last one provides timeliness in the packet delivery. We evaluate each QoS Level with several performance metrics such as PDR, Message Delivery Ratio, Duplicated and Retransmitted Packet Ratio and Packet Timeliness Ratio to demonstrate that our proposal provides significant improvements based on the increase of the PDR obtained.