• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.10
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• pp.979-988
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• 2012

The 3D structure of GDL for fuel cells was measured using high-resolution X-ray tomography in order to study material transport in the GDL. A computational algorithm has been developed to remove noise in the 3D image and construct 3D elements representing carbon fibers of GDL, which were used for both structural and fluid analyses. Changes in the pore structure of GDL under various compression levels were calculated, and the corresponding volume meshes were generated to evaluate the anisotropic permeability of gas within GDL as a function of compression. Furthermore, the transfer of liquid water and reactant gases was simulated by using the volume of fluid (VOF) and pore-network model (PNM) techniques. In addition, the simulation results of liquid water transport in GDL were validated by analogous experiments to visualize the diffusion of fluid in porous media. Through this research, a procedure for simulating the material transport in deformed GDL has been developed; this will help in optimizing the clamping force of fuel cell stacks as well as in determining the design parameters of GDL, such as thickness and porosity.

• Korean Journal of Head & Neck Oncology
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• v.11 no.1
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• pp.41-46
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• 1995

The pectoralis major myocutaneous flap represents a major contribution to head and neck cancer reconstruction. Its advantages are improved viability, one-stage reconstruction, and carotid protection. The oropharyngeal defect especially tonsillar area reveals valley shaped one with loss of a wide mucosal area. Using pectoralis major myocutaneous flap to this defect is sometimes difficult due to its natural figure of bulkiness. This article reviews our experience with patients undergoing 14 pectoralis major myocutaneous flap in carcinoma of the tonsillar area. Complications and their incidences were I total loss, 3 marginal loss, 2 minor seperation of suture, I wound infection and 2 hematoma. Most of the complications did not require a second procedure for reconstruction. Bulkiness of the flap and gravity force to the upper suture line were thought to be causes of the complications. Modification of the flap design with bilobular figure was useful to reduce its bulkiness at the folding area. More stable suture around hard palate was needed to overcome seperation of the suture.

• Journal of Fashion Business
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• v.7 no.1
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• pp.38-54
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• 2003

This study looked into the present status of e-mail marketing, which is conducted in local Internet fashion shopping malls and is being used as a one-to-one marketing method in the e-CRM concept so as to establish an effective e-mail marketing policy by grasping problems based on the current status and by presenting solutions to the problems. This study analyzed the e-mail letters received during a certain period of time by 30 professional Internet fashion shopping malls of with famous goods, brands and non-brands. Four individuals subscribed to shopping mall through the procedure for membership applying for e-mail services. The analysis showed that there were no shopping malls that were doing a differentiated e-mail marketing among Internet shopping malls. As for time factor, they were sending e-mail letters irregularly regardless of a certain cycle. And as for visual factor, they didnt have any standard for the content of the mail. As for content factor, the contents of their mail were not differentiated and all the same. The comparison of fashion malls showed that the brand shopping malls were the most active in e-mail marketing. On the basis of the problems, the direction for the effective e-mail marketing of Internet shopping malls are presented as follows: First, individualized contents fitting for customers should be developed, and differentiated mailing services should be provided thereby. Second, each shopping mall should make periodic tests of mailing to find out the optimal time and day to provide e-mail services to the customers at the designated time. Third, e-mail should be differentiated fitting for the website according to a certain on a certain standard for visual effects and the identity of shopping mall should be established. Firth, in the contents of e-mail, the image and message elements should be properly harmonized and creative policies should be made with interactive or recreational elements. Fifth, a homepage policy which can satisfy customers demand for information when the e-mail is clicked on..

• Archives of Plastic Surgery
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• v.37 no.5
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• pp.695-698
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• 2010

Purpose: Supernumerary nipple or polythelia is one of the developmental anomalies occurring at the embryonic stage and this anomaly usually arises from the milk line. While this atypical feature is determined during early developmental stage, it may not come out obviously or become troublesome until puberty or lactation. Moreover, sometimes it is confused with a pigmented nevus. Methods: Case 1, a 18-year-old woman with intramammary supernumerary breast consisted of another nipple with middle sized areola on the right lower breast was admitted for a $2.8{\times}3.1\;cm$-sized mass on the right breast which was starting appeared 1 year earlier. The preliminary cytological examination of the material obtained by needle aspiration biopsy from the mass was revealed by fibroadenoma with no malignant change. The patient had the surgical excision of the mass and accessory breast. Case 2, a 16 year-old woman admitted for intra-areolar polythelia of the left breast, even she doesn't have any family history of polythelia. Since she wanted surgical correction of her atypical nipple for aesthetic and psychological reasons, we reconstructed the areola using transposition flaps in an S-plasty design. Results: Case 1, the excised supernumerary nipple showed following histological features. In the superficial layer, an acanthotic and hyperpigmented epithelium with elongated rete ridges was found. In the dermis, there were follicles with hairs surrounded by hypertrophic sebaceous glands. In the deepest portion, abundant secretory glomerules and excretory ducts of apocrine gland type were observed. Case 2, follow-up visits 3 months after the procedure showed a satisfactory result with good shape and projection of the nipple. Conclusion: We report two cases of aberrant mammary tissue who underwent surgical correction, including complete breast (with nipple, areola, and glandular tissue) and intra-areolar polythelia according to the Kajava's classification, and the results were satisfactory.

• International Journal of Highway Engineering
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• v.13 no.2
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• pp.103-114
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• 2011

Usage of bicycle has been supported the universal reduction of energy consumption and $CO_2$. For the same purpose, new constructions for long length bike roads are planned in Korea. Recently, laboratory tests of physical properties and resistance against environmental loading about optimum mix design of roller compacted concrete, that have advantages of high structural performance by cement hydration and aggregate interlocking, simple construction procedure and low construction cost, are performed for the effective construction of new bike roads. However, properties of roller compacted concrete had different results between laboratory and field tests since it had different compaction method. Also, construction method of roller compacted concrete are not defined for the application of bike roads since it had different demand performance such as thin pavement thickness, low strength and etc with road pavements. Thus, in this experimental research was launched to evaluate the core properties, visual inspection, compaction ratio, water content, thickness reduction rate of roller compaction, skid resistance and roughness by experimental construction about variable mix proportion and compaction method based on laboratory test results. And construction method of roller compacted concrete pavement were suggested for the application of bike roads.

• The Transactions of the Korea Information Processing Society
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• v.3 no.7
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• pp.1812-1821
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• 1996

In this paper, firstly we describe the structure and the performance of our ICPS(Information Communicaion Processing System) which currently provides information retrieval services, and then make a proposal for the construction of the open-networking information communication infra-structure which enables us to fully pre-pare for the emerging information society. In detail, the structure and the methodology needed for the implementation of the billing function on behalf of all information providers by using the user access network number as a user identification number while guaranteeing the equivalent access to the multiple value-added networks, are suggested. Based on the above ideas, the AICPS(Advanced Information Communication Processing System) has been designed and implemented. Final system performance evaluation with the assumption of a poling system as a system model, shows that our system can handle 10,000 user simultaneously who are using V.34 28.8 kbps modems and the processing capacity is 288,000 packet/sec. This result is so far superior to our target performance established during the desingning procedure. Namely, our system was originally designed to accommodate only 960 users at the same time. By taking advantage of this excessive high performance of our system, many other users can easily access the new services which are accessible only throught the ISDN or the Internet.

• International Journal of Highway Engineering
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• v.9 no.1 s.31
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• pp.57-67
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• 2007

Many researches have recently discussed about the film thickness as a good substitute or supplement for VMA or other volumetric criteria in the design procedure. Some researchers have not only proposed the specific number for the recommended film thickness, but also introduced the new calculation procedures or concepts. Each model (index model and the virtual model) has its own advantages and disadvantages in terms of the ability to account for the volumetric properties of the mixture. In this paper, the modified virtual model was proposed to combine advantages from both models. However, it cannot be disregarded the way to determine the appropriate particle shape factors for different sources and sizes of aggregates. In order to evaluate the different calculation methods, mixtures with two aggregate sources and eight gradations were designed based on the dominant aggregate size range (DASR) porosity concept. Superpave indirect tensile test (IDT) and asphalt pavement analyzer (AEA) test were used to describe the performance of mixtures. Test results indicated that the virtual model, which is the same to the modified virtual model for sphere 1:1 case, is better than the conventional standard model to define the range of the film thickness to have better performance of asphalt mixtures.

• Journal of Astronomy and Space Sciences
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• v.24 no.4
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• pp.367-378
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• 2007

We present a software which we developed for the multi-purpose CCD camera. This software can be used on the all 3 types of CCD - KAF-0401E ($768{\times}512$), KAF-1602E ($1536{\times}1024$), KAF-3200E ($2184{\times}1472$) made in KODAK Co.. For the efficient CCD camera control, the software is operated with two independent processes of the CCD control program and the temperature/shutter operation program. This software is designed to fully automatic operation as well as manually operation under LINUX system, and is controled by LINUX user signal procedure. We plan to use this software for all sky survey system and also night sky monitoring and sky observation. As our results, the read-out time of each CCD are about 15sec, 64sec, 134sec for KAF-0401E, KAF-1602E, KAF-3200E., because these time are limited by the data transmission speed of parallel port. For larger format CCD, the data transmission is required more high speed. we are considering this control software to one using USB port for high speed data transmission.

• Journal of the Korea Concrete Institute
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• v.17 no.5 s.89
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• pp.709-716
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• 2005

The objective of this study is to develop a high ductile fiber reinforced mortar, ECC(Engineered Cementitious Composite) with using raw material commercially available in Korea. A single fiber pullout test and a wedge splitting test were employed to measure the bond properties in a matrix and the fracture toughness of mortar matrix respectively, which are used for designing mix proportion suitable for achieving strain-hardening behavior at a composite level. Test results showed that the properties tended to increase with decreasing water-cement ratio. A high ductile fiber reinforced mortar has been developed by employing micromechanics-based design procedure. Micromechanical analysis was initially peformed to properly select water-cement ratio, and then basic mixture proportion range was determined based on workability considerations, including desirable fiber dispersion without segregation. Subsequent direct tensile tests were performed on the composites with W/C's of 47.5% and 60% at 28 days that the fiber reinforced mortar exhibited high ductile uniaxial tension property, represented by a maximum strain capacity of 2.2%, which is around 100 times the strain capacity of normal concrete. Also, compressive tests were performed to examine high ductile fiber reinforced mortar under the compression. The test results showed that the measured value of compressive strength was from 26MPa to 34 MPa which comes under the strength of normal concrete at 28 days.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.11
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• pp.2535-2540
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• 2010

In traditional Publish/Subscribe system, the first procedure to deliver event from publisher to subscriber is that publisher publishes publisher's event to broker. Next step is that broker checks simple binary notion of matching : an event either matches a subscription or it does not. Lastly, broker delivers the event matched with subscriptions to the corresponding subscribers. In this system, information delivery has been accomplished in one way only. However, current some applications require two way delivery between subscriber and publisher. Therefore, we initiate an extended Publish/Subscribe system that supports two way delivery. Extended Publish/Subscribe system requires additional functions of delivering subscription to publisher and especially deciding top-n subscriptions using priority because broker might has a number of subscriptions. In this paper, we propose two priority retrieval techniques based on SIF using IS-List with deciding priority among subscriptions and defining SIF(Specific Interval First). The performance measurements show that RSO(resulting set sorting) technique results in better performance in index creation time and ITS&IS(insertion time sorting and inverse search using stack) technique results in better performance in search time.