• Journal of Biosystems Engineering
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• v.37 no.4
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• pp.258-264
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• 2012

Purpose: This review aims at introducing 3 modeling approaches classified into 3 categories based on the purpose (estimation or prediction), structure (linear or non-linear) and phase (steady-state or dynamic-state); 1) statistical approaches, 2) kinetic modeling and 3) mechanistic modeling. We hope that this review can be a useful guide in the model-based approach of calcium metabolism as well as illustrates an application of engineering tools in studying biosystems. Background: The meaning of biosystems has been expanded, including agricultural/food system as well as biological systems like genes, cells and metabolisms. This expansion has required a useful tool for assessing the biosystems and modeling has arisen as a method that satisfies the current inquiry. To suit for the flow of the era, examining the system which is a little bit far from the traditional biosystems may be interesting issue, which can enlarge our insights and provide new ideas for prospective biosystem-researches. Herein, calcium metabolic models reviewed as an example of application of modeling approaches into the biosystems. Review: Calcium is an essential nutrient widely involved in animal and human metabolism including bone mineralization and signaling pathways. For this reason, the calcium metabolic system has been studied in various research fields of academia and industries. To study calcium metabolism, model-based system analyses have been utilized according to the purpose, subject characteristics, metabolic sites of interest, and experimental design. Either individual metabolic pathways or a whole homeostasis has been modeled in a number of studies.

• Fire Science and Engineering
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• v.27 no.2
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• pp.75-79
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• 2013

The present study measured the light transmission to quantify the smoke density(smoke mass concentration) through the doorway in a compartment fire and performed the uncertainty analysis to evaluate the reliability of the measurement technique. The optical light extinction method based on Bourguer's law was applied to estimate the smoke density of doorway exhausting smoke flow in upper layer of a compartment for methane gas fires. The measurement uncertainty of the light extinction measurement was evaluated for the light transmittance, path length, and specific mass extinction coefficient and the expanded uncertainty was estimated about 20% with confidence level of 95%. The mean smoke density through the doorway for the methane fire was calculated for quasi-steady fire and the smoke density linearly increased as the GER increased.

• Structural Engineering and Mechanics
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• v.32 no.3
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• pp.399-406
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• 2009

A three-dimensional panel system, which was offered as a new method for construction in Jordan using relatively high strength modular panels for walls and ceilings, is investigated in this paper. The panel consists of two steel meshes on both sides of an expanded polystyrene core and connected together with a truss wire to provide a 3D system. The top face of the ceiling panel was pored with regular concrete mix, while the bottom face and both faces of the wall panels were cast by shotcreting (dry process). To investigate the structural performance of this system, an extensive experimental testing program for ceiling and wall panels subjected to static and dynamic loadings was conducted. The load-deflection curves were obtained for beam and shear wall elements and wall elements under transverse and axial loads, respectively. Static and dynamic analyses were conducted, and the performance of the proposed structural system was evaluated and compared with a typical three dimensional reinforced concrete frame system for buildings of the same floor areas and number of floors. Compressive strength capacity of a ceiling panel is determined for gravity loads, while flexural capacity is determined under the effect of wind and seismic loading. It was found that, the strength and serviceability requirements could be easily satisfied for buildings constructed using the three-dimensional panel system. The 3D panel system is superior to that of conventional frame system in its dynamic performance, due to its high stiffness to mass ratio.

• Industrial Engineering and Management Systems
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• v.12 no.4
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• pp.306-316
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• 2013

The semiconductor industry has grown rapidly, and subsequently production planning problems have raised many important research issues. The reentrant flow-shop (RFS) scheduling problem with time windows constraint for harddisk devices (HDD) manufacturing is one such problem of the expanded semiconductor industry. The RFS scheduling problem with the objective of minimizing the makespan of jobs is considered. Meeting this objective is directly related to maximizing the system throughput which is the most important of HDD industry requirements. Moreover, most manufacturing systems have to handle the quality of semiconductor material. The time windows constraint in the manufacturing system must then be considered. In this paper, we propose a hybrid genetic algorithm (HGA) for improving chromosomes/offspring by checking and repairing time window constraint and improving offspring by left-shift routines as a local search algorithm to solve effectively the RFS scheduling problem with time windows constraint. Numerical experiments on several problems show that the proposed HGA approach has higher search capability to improve quality of solutions.

• Journal of the Korean Institute of Gas
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• v.16 no.6
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• pp.136-142
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• 2012

Thermodynamic equations for the electric power and temperature in a turbo expander generator (TEG) using pressure energy in a natural gas line are derived. From the equations, it was shown that dominant factor is not the pressure difference but the pressure ratio. The high energy level in the inlet of TEG can be made from nearly no expense of electric energy input, which means TEG can be treated as one of newly available clean energy source. If a post heating method is chosen to heat up expanded natural gas, the usage of cold energy is possible without a refrigeration cycle. The combined TEG and refrigeration system enhances economic benefit much more.

• International Commerce and Information Review
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• v.11 no.4
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• pp.289-312
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• 2009

Under the circumstance of increasing international trade volumes and limitation of customs human resources, it is necessary to shift the customs' revenue collection activities and audit method from a transaction-based approach to an account-based approach. Thus, in 1997, U.S. Customs services established the Account Management Program. The Account Management Program is designed to increase importer compliance and improve customer service through one-on-one interaction with business entities and a designated Customs representative(Account Manager). The Account Management Program is a comprehensive process that includes the following stages and activities ; selection of a potential Account, establishment of the Account, management of the Account. In 2009, Korea Customs service introduced and executed the Account Management Program. But owing to its early stages, Korea Customs service does not suggest effective direction of development of the AM program. So I can propose the following improvements of the Account Management Program in Korea. Firstly, the Account Managers have to be assigned more traders than AEOs(Authorized Economic Operators). Secondly, it is necessary that Customs service appoints part-time port Account Managers to help more traders to improve customs compliance. Thirdly, thought should be given as to Account can be expanded to encompass both small and medium enterprises(SME) by providing customs brokers managing their customs business on the behalf of the SME with the Account Managers. Lastly, Customs service has to establish performance measures and action plan for the Account Management Program.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.22 no.4
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• pp.449-453
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• 2000

Soft tissue expansion is widely used technique in oral & maxillofacial reconstruction and provide new method of reconstruction in posttraumatic alopecia, post burn, wide scar, congenital deformity, benign tumor, tattoo, etc. Expanded tissue flaps have the advantage of increased vascularity, proximity to the defect, and similarity of color and texture. They also preclude the need to advance flaps from distant sites. Tissue expansion can be used to form a well vascularized cavity to accomodate and nourish bone grafts. The following report describes the uses of tissue expanders by allowing bone grafting to correct both soft and bony defects of mandibular region

• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1333-1336
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• 2014

Expanded polytetrafluoroethylene (ePTFE) grafts have been used as vascular access for many patients suffering from end stage renal disease. However, the vascular graft can cause significant clinical problems such as stenosis or thrombosis. For this reason, many studies have been performed to make drug eluting graft, but initial burst is major problem in almost drug eluting systems. Therefore we used biodegradable polymer to reduce initial burst and make sustained drug delivery. The ePTFE grafts were dipped into a paclitaxel-dissolved solution and then PLGA-dissolved solution was passed through the lumen of ePTFE. We analyzed whether the dose of paclitaxel is enough and the loading amount of PLGA on ePTFE graft increases according to the coating solution's concentration. Scanning electron microscope (SEM) images of various concentration of PLGA showed that the porous surface of graft was more packed with PLGA by tetrahydrofuran solution dissolved PLGA. In addition, in vitro release profiles of Ptx-PLGA graft demonstrated that early burst was gradually decreased as increasing the concentration of PLGA. These results suggest that PLGA coating of Ptx loaded graft can retard drug release, it is useful tool to control drug release of medical devices.

• Architectural research
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• v.12 no.2
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• pp.23-30
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• 2010

The study of the expression of architectural glass has recently expanded due to various factors such as the development of architectural technology, the reinforcement of environmental standards, an increased interest in energy saving, and the commercialism of the exterior of buildings. The background for restoring the tactile capability of the sense of sight has been prepared by agitating oculocentricism pertaining to the Renaissance era. The restoration of tactility can be considered in two ways. One is the tactility 'perceived' through complex experiences and the other is the tactility 'sensed' from the challenges on the materiality of the glass itself. Perceptual tactility is achieved from compound visual experiences and connecting these complex experiences in the brain. Sensible tactility, in contrast to perceptual tactility, is a more direct tactility which works within the nervous system, bypassing the brain. This is attained by reversion of the materiality, tectonics and connection method of the glass. Among rare examples, Laminata House built in Leerdam, Netherlands is a fine example of direct and sensible tactility. In this paper, the process of restoring tactility in architecture is studied at each stage based on the restoration of tactility in painterly aesthetics.

• Journal of Agricultural Extension & Community Development
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• v.16 no.4
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• pp.687-711
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• 2009

Recently, environmental-friendly agriculture (EFA) has been pointed out as an alternative for the change of our agricultural conditions. But the excessive amount of nutrients have been used to farmland since 1960s, when the intensive farming method called "High-Input, High-Yield" was expanded in earnest. This study was conducted to examine and compare farmers' purchasing and using fertilizer. For these purpose, data were gathered from a total of 326 farmers of the nation wide (greenhouse horticulture 60, upland cultivating 177, fruit-growing 89). The findings were as follows: First, 70.6% of greenhouse horticulture farmers, 89% of upland-cultivating farmers, 76.3% of fruit-growing farmers purchased fertilizer in Nong-hyup (farmers' cooperative organization). Second, only 54.2% of the greenhouse horticulture farmers, 60.2% of the upland cultivating farmers and 70.4% of the fruit-growing farmers recognized the optimum level of fertilizer. So, governmental organizations and agricultural technology center should carry out various programs for informing the farmers of the right way to use fertilizer and to practice EFA.