• Journal of Hydrogen and New Energy
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• v.19 no.3
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• pp.232-238
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• 2008

Research has been proceeded on fuel cell which is fueled by hydrogen. Polymer electrolyte membrane fuel cell (PEMFC) is promising power source due to high power density, simple construction and operation at low temperature. But it has problems such as high cost, temperature dependent performance. These problems could be solved by experiment which is useful for analysis and optimization of fuel cell performance and heat management. In this paper, when hydrogen flows constantly at the stoichiometry of ${\xi}=1.6$, the performance of the fuel cell stack was increased and the voltage difference between each cells was decreased according to the increase of air stoichiometry by 2.0, 2.5, 3.0. Therefore, the control of air flow rate in the same gas channel is important to get higher performance. Purpose of this research is to expect operation temperature, flow rate, performance and mass transportation through experiment and to help actual manufacture of PEM fuel cell stack.

• Journal of Hydrogen and New Energy
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• v.26 no.2
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• pp.136-147
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• 2015

Dead-ended operation of Proton Exchange Membrane Fuel Cell(PEMFC) provides the simplification of fuel cell systems to reduce fuel consumption and weight of fuel cell. However, the water accumulation within the channel prohibits a uniform supply of fuel. Optimization of the purge strategy is required to increase the fuel cell efficiency since fuel and water are removed during the purge process. In this study, we investigated the average voltage output which depends on two interrelated conditions, namely, the supply gas pressure, purging valve open time. In addition, flow visualization was performed to better understand the water build-up on the anode side and cathode side of PEMFC in terms of a variety of the current density. We analyzed the correlation between the purge condition and water flooding.

• Journal of Information Technology Applications and Management
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• v.23 no.2
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• pp.81-95
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• 2016

Software export is very important for developing the domain software industry. Up to now, the study related in this issue is not enough even if exports are not activated. In our study, we treated and analyzed the three SME cases that have each successful record in recent years focusing to sales channels establishment and product localization. This study was done by interviewing the marketing directors mainly, and applied email exchanges, phones, and document analyses. Some implications can be addressed for the potential SME software exports. In the perspectives of sales channels building, the trust for product and firm itself is needed to have a good offshore partners. These are required to make the good relationship with partners, brand value's diffusion, and technical competency. As for product localization, the customization is important to meet the needs for local users effectively. So it is desirable to accept the advisory suggestions from the local consulting experts or representative customers. And the joint export strategy using the platform by linking some related products is effective for SME's software product's export.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.10
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• pp.41-44
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• 2014

In full-duplex wireless communication, spectral efficiency can be improved over half-duplex communication system. In this paper, we consider full-duplex multiple-user (MU) multiple-input multiple-output (MIMO) system in which inter-user interference may degrade the performance of the full-duplex system. We propose a downlink power allocation technique at base station that can maximize the spectral efficiency only with the statistical information about the inter-user interference channel.

• ETRI Journal
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• v.38 no.2
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• pp.314-325
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• 2016

This paper examines the resource gain that can be obtained from the creation of clusters of nodes in densely populated areas. A single node within each such cluster is designated as a "hotspot"; all other nodes then communicate with a destination node, such as a base station, through such hotspots. We propose a semi-distributed algorithm, referred to as coordinated cognitive tethering (CCT), which clusters all nodes and coordinates hotspots to tether over locally available white spaces. CCT performs the following these steps: (a) groups nodes based on a modified k-means clustering algorithm; (b) assigns white-space spectrum to each cluster based on a distributed graph-coloring approach to maximize spectrum reuse, and (c) allocates physical-layer resources to individual users based on local channel information. Unlike small cells (for example, femtocells and WiFi), this approach does not require any additions to existing infrastructure. In addition to providing parallel service to more users than conventional direct communication in cellular networks, simulation results show that CCT can increase the average battery life of devices by 30%, on average.

• Spatial Information Research
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• v.21 no.5
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• pp.1-6
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• 2013

Trying to estimate variations of the riverbed is basic and important for river management. When new dam constructed in upstream and a structure were planned, impact of the riverbed changes in downstream should be considered for stably maintained and sustained rivers in the future. In this study, long-term riverbed changes analyzed using aerial photographs in Naeseongcheon. Also applying one-dimensional numerical model, GSTARS analyzed the effects of bed deformation in critical points. Based on Changing Patterns of long-term riverbed, it is possible that after the dam was built, to explore how to manage Naeseongcheon.

• Information Systems Review
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• v.9 no.2
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• pp.67-83
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• 2007

This study deals with an important but ignored topic in previous IS research, so called trustee issue. The purpose of this study is to compare the influencing strengths of trust types on the customers' intention to adopt IT services. The research results showed that the influences of the customers' self-trust and the trust in mobile channel on the customers' intention to adopt mobile banking are statistically significant. However, unlike the results of previous research, it was revealed that the customers' trust in vendors is statistically insignificant in mobile banking services.

• Korean journal of food and cookery science
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• v.22 no.2 s.92
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• pp.250-257
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• 2006

Foodservice industry and distribution business could make mutual prpgress when they join forces in responding to environmental uncertainty in an efficient manner. The purpose of this study was to examine the relational characteristics of domestic food service businesses and distribution firms in conjunction with the distribution channels and ensuing conflicts between them, to present possible alternatives on and how they should communicate with each other to achieve a satisfactory result. The relational characteristics and ensuing conflicts of food service businesses and distribution firms appeared to be significantly characterized by incongruities of target, role and perception. The types of relational characteristics that were triggered by the disagreement of roles and perception combined to decrease the intensity of the relational commitment. A satisfactory transactional relationship served to ease their conflicts caused by perceptual disagreement, and the soos of conflicts that were rooted in the discord of roles and of perception that increased the degree of relational commitment. As for relational performance, relational commitment, satisfaction with distribution channel and satisfaction with suppliers allowed them to maintain their relationship on a long-term basis.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.9
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• pp.4363-4365
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• 2016

Background: The complex anatomy of the pancreaticobiliary duct was crucial in management of pancreatic and biliary tract disease. Materials and Methods: Fresh specimens of pancreas, common bile duct (CBD), and duodenum were obtained en bloc from autopsies of 160 patients. Results: Ninety-three male and 67 female patients were included. The length of the pancreas ranged from 9.8-20 cm (mean, 16.20 +/- 1.70 cm). The intrapancreatic portion of the CBD showed patterns of three types: most common (85.30%) was type A, in which the anterior surface of the common bile duct was totally covered, while its posterior surface was partially covered, by the pancreatic parenchyma. On dissection of the accessory duct of Santorini, the accessory duct was traceable to the duodenal wall in 67.6%. The anatomy of the Wirsung-choledochus confluence was grouped into five different types. The common channel was found in 75.60% and its length varied from just a common junction (so-called "V-type" anatomy) to 15 mm (Y-type-b). Separate papillae (so-called "II-type") were found in 15.3% of specimens. Conclusions: Several important points regarding the anatomy of the pancreaticobiliary junction and pancreatic ductal system were illustrated in this study.

• YAKHAK HOEJI
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• v.59 no.4
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• pp.177-183
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• 2015

The mechanism of melanogenesis induced by cyclosporin A (CsA) was investigated in B16 melanoma cells. CsA stimulated the production of melanin in a dose-dependent manner in the cells. In addition, CsA increased intracellular $Ca^{2+}$ concentration in a dose-related fashion. Treatment with BAPTA/AM, an intracellular $Ca^{2+}$ chelator significantly inhibited the CsA-induced intracellular melanin synthesis. CsA profoundly induced $Cl^-$ efflux, which was significantly blocked by niflumic acid (NFA) and flufenamic acid (FFA), specific and nonspecific inhibitors of $Ca^{2+}$-activated $Cl^-$ channels (CaCCs), respectively. Furthermore, these inhibitors of CaCCs significantly inhibited the CsA-induced stimulation of melanin synthesis. Taken together, these results suggest that the activation of CaCCs may play an important role in the CsA-induced stimulation of melanin synthesis in B16 cells. These results further suggest that CaCCs may be a good target for the management of hyperpigmentation of the skin reported in the patients treated with CsA.