• Journal of Institute of Control, Robotics and Systems
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• v.12 no.11
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• pp.1144-1155
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• 2006

Digital communication networks have become a core technology in advanced building automation systems. BACnet(Building Automation and Control networks) is a standard data communication protocol designed specifically for building automation and control systems. BACnet adopts Master-Slave/Token-Passing(MS/TP) protocol as one of its field level networks. In this study, we introduce a method of implementing a bandwidth allocation scheme in the MS/TP protocol. The bandwidth allocation scheme improves the capability of real-time communication of the original MS/TP protocol. The bandwidth allocation scheme introduced in this paper can be easily implemented in the existing MS/TP protocol with a slight modification. In this study, we actually developed the hardware and firmware of the modified MS/TP communication module in which the bandwidth allocation scheme is implemented. Using the modified MS/TP communication module, we developed an experimental model in order to examine the validity of the bandwidth allocation scheme in the MS/TP protocol. Experimental results show that the modified MS/TP protocol satisfies the requirements of real time communication for periodic and urgent messages of BACnet communication services.

• 전자공학회논문지 IE
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• v.48 no.1
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• pp.45-50
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• 2011

In this paper, different RFID tag types compliant with UHF frequency based RFID system were chosen to build RFID tag embedded concrete blocks. Then, by placing the tags in systematically varied depths of a concrete block, we could measure the RF signal attenuation pattern as the performance indicator of a specific concrete embedded RFID system. Experiments show that the concrete mixing ratio makes no significant difference in tag detection performance level. The significance of the developed RFID system lies in its capability of eliminating GPS's error and shadow area as well as providing smart infrastructure for supporting truly pervasive ubiquitous computing applications especially in outdoor environment.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.6
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• pp.545-552
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• 2016

As a future key industry, digital signage is being noticed that provides various type of contents and message through a digital display. In particular, korean digital signage industry gets a favorable evaluation for the high level of digital display industry and wired and wireless networking infrastructure. This paper discusses on not only the current status of digital signage in terms of the overall development and standardization, but the very recent technologies such as the ultra-high definition video and human perception that can be applied for future digital signage. Then, this paper concludes by deriving the problems with the current digital signage industry and presenting solutions for future vitalizations of digital signage.

• Journal of Pharmaceutical Investigation
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• v.26 no.4
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• pp.273-280
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• 1996

Chondroitin sulfate/gelatin microspheres containing dexamethasone 21-acetate were prepared by complex coacervation method and their release patterns were examined in vitro. Microspheres prepared with a small amount of crosslinking agent had smooth surface and few pores, but those with a large amount of crosslinking agent were more porous and less spherical. In vitro release patterns were varied by changing polymer/drug weight ratio and amount of crosslinking agent. The release rate of dexamethasone 21-acetate in the presence of collagenase was faster than that in the absence of collagenase. Anti-inflammatory effect of dexamethasone 21-acetate microspheres was more efficient than that of dexamethasone 21-acetate solution in carrageenan-induced arthritis in the rat. On the basis of the above results, we might expect the degradation and drug release rate of these microspheres to be regulated by the degree of crosslinking and the level of enzymes. In patients with severe rheumatoid arthritis who have high concentration of collagenase, more drug would be released from the microspheres. An intra-articular injection therapy of rheumatoid arthritis with desired release kinetics could be developed to enhance patient compliance and therapeutic index.

• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.824-831
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• 2013

Lightning electromagnetic fields are important issues for the evaluation of lightning induced overvoltage on power lines and for setting the appropriate protection level for power networks. Such electromagnetic fields are strongly dependent on lightning return stroke currents at different heights along the lightning channel. On the other hand, the ground reflection factor due to the difference between the return stroke channel impedance and the equivalent ground impedance at channel base can have an effect on the shape of the return stroke currents by entering additional reflected currents into the channel. In this paper, the effect of the ground reflection factor on the return stroke currents at different heights along a channel and the electromagnetic fields associated with the lightning channel at close distances are considered. Moreover, the behavior of the electromagnetic fields versus the reflection factor changes and the radial distance changes are considered and the results are discussed accordingly. The results illustrate that the reflection factor has a direct relationship with the values of the electromagnetic fields while this is usually ignored in earlier studies.

• Journal of Information Science Theory and Practice
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• v.3 no.1
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• pp.40-49
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• 2015

Nigeria's non-government organization (NGO) libraries for the visually impaired has over the years been at the forefront of information services provision to persons with visual impairment. This study adopted a survey research design to investigate use of alternative formats and perceptions of information services to the visually impaired, focusing on two purposively chosen NGO libraries for the visually impaired in Nigeria. Using a complete enumeration approach, data were gathered from 180 users of the libraries through the use of a structured questionnaire with a reliability score (${\alpha}=0.74$). Data from 112 (62.2%) of the 180 administered copies of a questionnaire that were retrieved were analysed. The study found that Braille materials had a high level of utilization ($\bar{x}=4.46$) and were the most frequently utilized (90.9%). Perception of information services by the visually impaired was positive while use of alternative formats was significantly and positively related to users' perception of information services (r = .041; p < 0.05). The study recommends improved transcription and investment in alternative formats and in e-resources. It also recommends collaborations to widen access as well as constant evaluation of services.

• Korean Journal of Pharmacognosy
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• v.31 no.4
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• pp.383-389
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• 2000

GRF (Korean Red Ginseng mixed formula) consists of six herbs such as Ginseng Radix rubra Koreana, Lycii Fructus, Artemisiae Capillaris Herba, Poria, and Glycyrrhizae Radix and Hoveniae Fructus. For the evaluation of hepatoprotective effect of GRF, the study was performed on protective effect against hepatic damage induced by galactosamine in vitro and ccl4 in vivo and also elucidate antioxidant activity. In vitro assay with 1.1 mM galactosamine, protection (%) was 44% (GR), and 58% (GRF-A) at 50 ug/ml. GRF effectively protected fatty degenertion and necrosis in murine hepatic damage induced by ccl4. For the -antioxidant study, GRF inhibited hemolysis of erythrocyte and decolored DPPH (2,2-diphenyl-l-picrylhydrazyl) free radical in a dose dependent manner more effetively than GR alone in vitro. GRF and GR significantly suppressed the time course $(1\;hr{\sim}6\;hr)-level$ of MDA (malondialdehyde) following AAPH (2,2'-azo-bis-(2-amidino -propane) dihydrochloride) treatment in vivo as compared with control data. From the results it can be concluded GR and GRF exerted the hepatoprotective effect by dint of antioxidant activity.

• Journal of Energy Engineering
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• v.8 no.4
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• pp.612-620
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• 1999

Environmental impact assessment in the step of the Life Cycle Assessment (LCA) measures relative values of importance or weight of the environmental load characterized in the inventory analysis. The weight measurements are used to evaluate the environmental load or the effect of the industrial product or technology. In this paper the Analytic Network Prpcess (ANP) is introduced to calculate a relative weighting of the environmental impact. The ANP is considered as one of the useful decision making framework and allow for more complex interrelationships, feedback, and inner/outer dependence among the decision level and factors. The weighting from the ANP may applied to obtain the overall evaluation value of environmental load.

• Journal of the Korean Solar Energy Society
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• v.31 no.2
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• pp.63-71
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• 2011

The remote-sensng campaign was performed at the Pohang Accelerator Laboratory where is located in a basin 6km inland from Yeongil Bay. The campaign aimed uncertainty assessment of Remtech PA0 SODAR through a mutual comparison with WindCube LIDAR, the remote-sensing equipment for wind resource assessment. The joint observation was carried out by changing the setup for measurement heights three times over two months. The LIDAR measurement was assumed as the reference and the uncertainty of SODAR measurement was quantitatively assessed. Compared with LIDAR, the data availability of SODAR was about half. The wind speed measurement was fitted to a slope of 0.94 and $R^2$ of 0.79 to the LIDAR measurement. However, the relative standard deviation was about 17% under 150m above ground level. Therefore, the Remtech PA0 SODAR is judged to be unsuitable for the evaluation of wind resource assessment and wind turbine performance test, which require accuracy of measurement.

• Nuclear Engineering and Technology
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• v.30 no.2
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• pp.112-127
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• 1998

The present study is to assess the applicability of the best-estimate thermal-hydraulic codes, RELAP5/MOD3.2 and CATHARE2V1.3U, to the analysis of thermal-hydraulic behavior in PWRs during midloop operation following the loss of RHRS. The codes simulate an integral test, BETHSY 6.94, which was conducted in the large scale test facility of BETHSY in France. The test represents the accident where the loss of RHRS occurs during midloop operation with the pressurizer and upper head vents open and the sight level indicator broken. Besides, the hot legs are half filled with water and the upper parts of the primary cooling system are filled with nitrogen, with a letdown line open and only one SG available. The purposes of this study are to understand the physical phenomena associated with reflux cooling in the 5G U-tubes when noncondensable gas is present under low pressure and to assess the applicability of the codes to simulate the loss of RHRS event by comparing the predictions with the test results. The results of the study may contribute to actual applications for plant safety evaluation and description of the emergency operating procedure.