• KDI Journal of Economic Policy
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• v.43 no.4
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• pp.23-44
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• 2021

This research attempts to provide an in-depth analysis of the public perceptions of inter-Korean economic cooperation. KDI survey data with a sample size of 1,000 were subjected to empirical analyses. By means of ordered logit estimations, we derive the following results. First, there is a significant effect of age on economic cooperation perceptions, where younger generations tend to be more negative. Second, the group who has positive view on the economic cooperation tends to prefer large-scale, domestic-entity-funded cooperation projects, whereas the group who has negative view tends to prefer small-scale projects and projects funded by international organizations. According to these results, prioritizing trade with the involvement of international organizations is likely to be an effective measure to alleviate potential political constraints and to achieve sustainable long-run economic cooperation systems when pursuing the economic cooperation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5634-5653
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• 2018

Internet of things (IoT) is based on a global dynamic information network with cloud services where a great number of devices (things) exchange data to provide added-value services and products. There are several commercial and open source IoT platforms available in the market to connect devices to internet; however, they have cost and operational constraints that make them not suitable for academic projects. In this work, an IoT platform, known as Novus-io, is introduced in order to support academic projects for undergraduate students. With this platform and proper training, undergraduate students from different majors (not only from information technology and electronics) are capable to upgrade their school projects with IoT functionalities. The objective of this approach is to provide to any undergraduate student skills and knowledge on IoT, so they will be prepared, in their imminent step toward professionalism, to understand the relevance of digital services in today's world.

• Journal of KIBIM
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• v.12 no.1
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• pp.10-22
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• 2022

Prefabricated bridges require strict management of tolerance during fabrication and assembly. In this paper, digital engineering models for prefabricated bridge components such as deck, girder, pier, abutment are suggested to support information delivery through the life-cycle of the bridge. Rule-based modeling is used to define geometry of the members considering variable dimensions due to fabrication and assembly error. DfMA(design for manufacturing and assembly) provides the rules for ease of fabrication and assembly. The digital engineering model consists of geometry, constraints and corresponding parameters for each phase. Alignment and control points are defined to manage tolerances of the prefabricated bridge during fabrication and assembly. Quality control by digital measurement of dimensions was also considered in the model definition. A pilot bridge was defined virtually to validate the suggested digital engineering models. The digital engineering models for DfMA showed excellent potential to realize prefabricated bridges.

• Journal of the Korean Society of Systems Engineering
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• v.17 no.2
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• pp.1-8
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• 2021

This study proposes a systems engineering approach for the development of an advanced planning & scheduling (APS) system for a cosmetic case manufacturing factory. The APS system makes production plans and schedules based on the injection process, which consists of 27 plastic injection machines in parallel to control recommended inventory of products. The system uses machine operation/failure information and defective product/work-in-process tracking information to support intelligent scheduling. Furthermore, a genetic algorithm model is applied to handle the complexity of heuristic rules and machine/quality constraints in this process. As a result of the development, the recommended inventory compliance rate is improved by scheduling the 30-day production plan for 15 main products.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1407-1424
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• 2024

In Pressurized Water Reactors, most of the failed fuel rods are often observed at the periphery of the fuel assembly, especially near the core baffle. The rod vibration-induced fretting wear is a significant failure mechanism strongly correlated with the coolant and support conditions. This paper presents a coupled vibration model of double-rod to predict the grid-to-rod fretting (GTRF) wear. A motion-dependent fluid force model is used to simulate the coolant cross flow, the gap constraints with asymmetric stiffness between spring and dimple on the vibration form, and the fretting wear are discussed. The results show the effect of the coupled vibration on the deterioration of wear, providing a sound theoretical explanation of some failure phenomena observed in the previous experiment. Exploratively, we analyze the impact of the baffle jet on the GTRF wear, which indicates that the high-velocity cross-flow will significantly affect the vibration forms while sharply changing the wear behavior.

• Annual Conference of KIPS
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• 2007.05a
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• pp.1195-1198
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• 2007

In this paper we study the problem of real time support in wireless sensor networks and propose a Real time Geographic Routing Protocol (ReGeo) which routes a packet towards the destination based on a compromise between distance and queue count to reduce traffic concentration wherever it has been determined to be too high and uses Gradient Table to store the route satisfying the delay constraints. We describe our prototype implementation of ReGeo Routing in TOSSIM - a TinyOS mote simulator. The simulation results show that the proposed routing protocol not only increases the packet delivery ratio but also keeps overall End to End Delay under a bounded value.

• Journal of the Korean earth science society
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• v.30 no.7
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• pp.834-844
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• 2009

Two-dimensional magnetotelluric (MT) inversion algorithm using minimum support (MS) stabilizer functional was implemented in this study to enhance the contrast of inverted images. For this implementation, this study derived a formula in discrete form for creeping model updates in the least-squares linearized inversion. A spatially varying regularization parameter determination algorithm, which is known as ACB (Active Constraint Balancing), was also adopted to stabilize the inversion process when using MS stabilizer as a model constraint. Inversion experiments for a simple isolated body model show well the feature of MS stabilizer in concentrating the anomalous body compared with the second-order derivative model constraint. This study also compared MS stabilizer and the second-order derivative model constraints for a model having multiple anomalous bodies to show the applicability of the algorithm into field data.

• The Korean Journal of Rehabilitation Nursing
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• v.5 no.1
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• pp.27-37
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• 2002

During acute stages of hospitalized stroke patients, family caregivers face many challenges. They often experience emotional distress, social isolation, and financial constraints. However, the burden of caregiving of stroke patients in acute stages has never been studied properly. The purpose of this study was to investigate the factors related to the caregivers' burden with acute stroke. The subjects were 123 acute stroke patients and their caregivers who were admitted to neurology and neurosurgery units at Dan Kook University Hospital in Chung-Nam area. An interview was performed with the use of standardized questionnaire which included data pertaining to the patients/caregivers characteristics, caregiver burden (Modified Zarit's Burden Scale), and social support (Personal Resource Questionnaire). Our results showed that the mean burden score was 3.11, indicating high level of burden. Among the sub-domain scores, financial burden was the highest. In univariate analysis, the factors related to caregiver burdens were: inability to communicate between patients and caregiver(p<.001); low cognitive function of the patients(p<.001); low level of ADL(p<.001); the gender of caregiver(p<.001); the current employment status of caregivers(p<.01); the presence of social support for caregiver(p<.001); and the availability of alternative caregivers(p<.001). In multiple regression analysis, social support for family caregivers (87%), low level of patient's cognition (2%), availability of 2nd caregiver (1%), and gender of caregiver (female, 0.4%) were significant explanatory factors of overall burden. The caregivers' burden in acute stages during hospitalization following stroke was high. Recognition of high levels of caregivers' burden and those relating factors affecting caregiver burden may allow us to develop different nursing strategies to unload the level of burden for caregivers in acute stages of stroke.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.5
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• pp.543-551
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• 2011

The paper deals with the comparative study of design optimization based on various approximation techniques in strength design of riser support structure installed on floating production storage and offloading unit(FPSO) using offshore operation loading conditions. The design optimization problem is formulated such that structural member sizing variables are determined by minimizing the weight of riser support structure subject to the constraints of structural strength in terms of loading conditions. The approximation techniques used in the comparative study are response surface method based sequential approximate optimization(RBSAO), Kriging based sequential approximate optimization(KBSAO), and the enhanced moving least squares method(MLSM) based approximate optimization such as CF(constraint feasible)-MLSM and Post-MLSM. Commercial process integration and design optimization(PIDO) tools are employed for the applications of RBSAO and KBSAO. The enhanced MLSM based approximate optimization techniques are newly developed to ensure the constraint feasibility. In the context of numerical performances such as design solution and computational cost, the solution results from approximate techniques based design optimization are compared to actual non-approximate design optimization.

• Journal of Communications and Networks
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• v.2 no.1
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• pp.5-17
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• 2000

cdma2000 offers several enhancement as compared to TIA/EIA-95, although it remains fully compatible with TIA/EIA-95 systems and allows for a smooth migration from one to the other-Major new capability include:1)connectivity to GSM-MAP in addition to IP and IS-41 networks; 2) new layering with new LAC and MAC architectures for improved service multiplexing and QoS management and efficient use of radio resource ;3) new bands and band widths of operation in support of various operator need and constraints, as well as desire for a smooth and progressive migration to cdma 2000; and 4) flexible channel structure in support of multiple services with various QoS and variable transmission rates at up to 1 Mbps per channel and 2 Mbps per user. Given the phenomenal success of wireless services and desire for higher rate wireless services. improved spectrum efficiency was a major design goal in the elaboration of cdma2000. Major capacity enhancing features include; 1) turbo coding for data transmission: 2)fast forward link power control :3) forward link transmit diversity; 4) support of directive antenna transmission techniques; 5) coherent reverse link structure; and 6) enhanced access channel operation. As users increasingly rely on their cell phone at work and at home for voice and data exchange, the stand-by time and operation-time are essential parameters that can influence customer's satisfaction and service utilization. Another major goal of cdma2000 was therefore to enable manufacturers to further optimize power utilization in the terminal. Major battery life enhancing features include; 1) improved reverse link performance (i.e., reduced transmit power per information bit; 2) new common channel structure and operation ;3) quick paging channel operation; 4) reverse link gated transmission ; and 5) new MAC stated for efficient and ubiquitous idle time idle time operation. this article provides additional details on those enhancements. The intent is not to duplicate the detailed cdma2000 radio access network specification, but rather to provide some background on the new features of cdma2000 and on the qualitative improvements as compared to the TIA/EIA-95 based systems. The article is focused on the physical layer structure and associated procedures. It therefore does not cover the MAC, LAC, radio resource management [1], or any other signaling protocols in any detail. We assume some familiarity with the basic CDMA concepts used in TIA/EIA-95.