• Journal of Energy Engineering
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• v.23 no.3
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• pp.125-131
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• 2014

In order to increase landfill gas (LFG) production with food waste leachate, this study was confirmed to be acidogenetic conditions for landfill site injection. Thereby, it was conducted for acidogenetic treatments to determine the decrease in viscosity and VFA production. After acidogenesis treatments, solubility of food waste leachate increased approximately 15%, and as a result, UASB and CSTR were similar by reactor type using the change of retention time. Based on the result of the change in viscosity by reactor type, efficiency of UASB showed approximately 11.38% of higher decrease in viscosity as $76.95{\pm}3.27%$ vs. CSTR. Also, VFA production showed the higher increase of 2.01 times (UASB) and 1.76 times (CSTR) respectively at the point of increasing retention time from 3 to 5 days. From the above results, efficiency of UASB in a reactor was relatively higher because large molecular lead to longer retention time than small molecular due to having screen effect in the fixed media.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.65-73
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• 2016

Peer-to-Peer (P2P) systems with super-peer overlay networks show combined advantages of both hybrid and pure P2P systems. Super-peer is a special peer acting as a server to a cluster of generic peers. Organizing a super-peer network is one of important issues for P2P systems with super-peer networks. Conventional P2P systems are based on two-level hierarchies of peers. One is a layer for generic peers and the other is for super-peers. And it is usual that super-peer networks have forms of random graphs. However, for accommodating a large-scale collection of generic peers, the super-peer network has also to be extended. In this paper, we propose a scheme of hierarchically constructing super-peer networks for large-scale P2P systems. At first, a two-level tree, called a simple super-peer network, is proposed, and then a scheme of generalizing and then extending the simple super-peer network to multi-level super-peer network is presented to construct a large-scale super-peer network. We call it an extended super-peer network. The simple super-peer network has several good features, but due to the fixed number of levels, it may have a scalability problem. Thus, it is extended to k-level tree of a super-peer network, called extended super-peer network. It shows good scalability and easy management of generic peers for large scale P2P system.

• Journal of Broadcast Engineering
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• v.12 no.2
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• pp.80-92
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• 2007

IPTV Services that is representative union service of broadcasting and telecommunication need guarantee of QoS, efficiency of multicasting, and hish bandwidth on the network. Because typical TDM based metro transport network was designed by transporting fixed voice traffic with stable and recovering method, it has a defect of bottleneck and a waste of bandwidth for acceptance of data traffic with burst feature and then all of data are treated equally at the transport network because it cannot classify between advanced high end service and best effort low end service. for completely resolving this kind of problem about increasing burst traffic and QoS issues, firstly we need to new design for transport network. This paper presents transformation method from TDM based metro transport network to packet based transport network and advantage and effectiveness of packet based transport network and also indicates technical factor and characters about method of packet transport system. As a result of research, the Packet Transport System, which is a transmission network for packet delivery, take in not only a specific character of legacy TDM but QoS, Multicast and high bandwidth, then, it is able to keep an effective bandwidth and a stabilized performance of packet transmissions. Additionally, if a fault be occurred on an optical link, the system is able to guarantee a differential QoS by an each service class using an algorithm to make certain of a traffic existence and contain a protective mechanism.

• Journal of Broadcast Engineering
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• v.12 no.2
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• pp.128-136
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• 2007

Since the multi-view video is a set of video sequences captured by multiple array cameras for the same three-dimensional scene, it can provide multiple viewpoint images using geometrical manipulation and intermediate view generation. Although multi-view video allows us to experience more realistic feeling with a wide range of images, the amount of data to be processed increases in proportion to the number of cameras. Therefore, we need to develop efficient coding methods. One of the possible approaches to multi-view video coding is to generate an intermediate image using view interpolation method and to use the interpolated image as an additional reference frame. The previous view interpolation method for multi-view video coding employs fixed size block matching over the pre-determined disparity search range. However, if the disparity search range is not proper, disparity error may occur. In this paper, we propose an efficient view interpolation method using initial disparity estimation, variable block-based estimation, and pixel-level estimation using adjusted search ranges. In addition, we propose a multi-view video coding method based on H.264/AVC to exploit the intermediate image. Intermediate images have been improved about $1{\sim}4dB$ using the proposed method compared to the previous view interpolation method, and the coding efficiency have been improved about 0.5 dB compared to the reference model.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.6
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• pp.601-608
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• 2008

The objective of this study was to evaluate the effect of ozonation as pretreatment on the removal of dissolved or biodegradable organic matter(DOM or BOM), the variance of DOM fractionation, and microbial regrowth by pilot-scale granular activated carbon processes in which adsorption and biodegradability was proceeding due to long time operation. Regardless of point of ozonation applied, GAC processes with ozonation(i.e., Ozonation combined with GAC Filter-adsorber; Pre O$_3$ + F/A, Ozonation combined with GAC adsorber; Post O$_3$ + GAC) compared with GAC processes without ozonation(i.e., GAC Filter-adsorber; F/A, GAC adsorber; GAC) removed approximately 10 to 20% more of DOC, hydrophilic DOM(HPI), BDOC and AOC after long period of operation that biological activity was assumed to happen. Ozonation was not found to have a significant effect on the removal of DOC, but caused the decrease of AOC by approximately 20%. It was found that the fixed bacterial biomass on GAC media did not show a significant difference between the GAC with ozonation and GAC without ozonation as pre-treatment, whereas the HPC of column effluent was more biostable at Post O$_3$ + GAC compared with F/A or GAC.

• The Journal of the Korea Contents Association
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• v.18 no.8
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• pp.262-271
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• 2018

The purpose of this study is to identify the aspect of the single-parent family discourse in the TV documentary. Considering the fact that the normal family myth shows limitations in reality, it is necessary to expand the single-parent family research based on various analysis subjects. For this purpose, the study conducted a narrative analysis of KBS1's documentary 'Gong-gam' (2015), which deals with single daddy and single mom's stories at the same time. Single daddy and single mom are commonly described as overcoming the 'deprived situation'. However, asymmetric description was outstanding in that single daddy is depicted as performing the role of mother as well whereas the single mom appears to be unable to perform even the mother's role. Also, the narrative in the documentary compares broken family with normal family and reproduces the fixed sex role, which considers the problem an individual area. Such description can be seen as a process of persuading them into a "modified normal family myth". However, as the fundamental problem is the absence of new discourse, the role of the media to reproduce and expand the conflicting family discourses will be important.

• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.71-77
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• 2015

A fluidized biofilter was filled with Pseudomonas sp. and Bacillus cereus/thuringiensis-fixed waste-tire crumb media and was run to treat authentic textile-dyeing wastewater mixed with alkaline polyester-weight-reducing wastewater. As a result, its removal efficiency of $COD_{Cr}$ and color were 75~80% and 67%, respectively. In addition, upon constructing hybrid-recirculating system composed of the fluidized biofilter and a 450 W-UV/photocatalytic reactor, only fluidized biofilter was run bypassing UV/photocatalytic reactor at stage I. Subsequently, the hybrid system was continuously run at stage II-i, ii and iii. At stage II-i, the total removal efficiency of $COD_{Cr}$ was enhanced to be 80~85%, compared to 75% at stage I, owing to 20~30% removal efficiency of the UV/photocatalytic reactor. However, at stage II-i, the total removal efficiency of color was enhanced to be 65~70%, compared to 45~65% at stage I, even though the removal efficiency of the UV/photocatalytic reactor was tantamount to merely 0~5%. As far as the removal efficiency of fluidized biofilter of the hybrid-recirculating system is concerned, its removal efficiency of color was enhanced by the synergy effect of the hybrid-recirculating system unlike $COD_{Cr}$. Besides, despite of the increase of hybrid-recirculating system-recycle ratio, the deactivation of photo-catalytic activity was scarcely observed to eliminate the color while its irreversible deactivation was observed to eliminate $COD_{Cr}$.

• Journal of Periodontal and Implant Science
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• v.34 no.2
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• pp.303-315
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• 2004

The success and failure of dental implants depends on various factors such as patient's systemic status, quantity and quality of surrounding bone, presence or absence of marginal infection and mechanical loading condition. The measurement of crestal bone changes around the implants is implemental to evaluate the success and long-term prognosis of the implant. This study was to evaluate the cumulative survival rate of the implants which had been placed in the Department of Periodontics, Chonnam National University Hospital between 1992 and 2003, and to observe the crestal bone loss around the implants which had at least 2 consecutive periapical radiographs after connecting the transmucosal abutment. The radiographs were scanned and digitalized, and the crestal bone levels on the mesial and distal surface of implants were measured using Image analyzer (Image Pro Plus, Media Cybernetics, USA), immediately after implant placement, at 2nd surgery, and 3 months, 6 months, 1 year, and every year thereafter. Any bone loss was not observed during the period between the 1stand 2nd surgery, and the bone loss was 0.86 ${\pm}$ 0.92 mm for the first year of loading after connecting the transmucosal abutment. After 1 year of loading, annual bone loss was 0.1 ${\pm}$ 0.27 mm, and total bone loss was 0.90 ${\pm}$ 0.80 mm (during the average follow-up periods of 22.5 ${\pm}$ 25.6 Mos), The implant, with smooth surface, in the mandible, and with the fixed bridge prosthesis showed greater bone loss, compared to those, with the rough surface, in the maxilla and with single crown. In systemically diseased patients (including DM or osteoporosis), the greater bone loss was observed. The cumulative survival rate among 432 implants was 94.10% for 7 years. Among 15 failed implants, 9 implants were removed due to mobility from disintegration of bone-implant interface. From this results, crestal bone loss around the implants were greatest during 1 year after transmucosal abutment connection, and various factors could affect peri-implant bone loss. To prevent and predict the bone loss around the implants and improve the prognosis, further comprehensive maintenance and follow-up schedules are required.

• 한국HCI학회:학술대회논문집
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• 2008.02b
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• pp.470-474
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• 2008

The image as a media has changed consistently since it was first introduced. According to these changes, the image has been reproduced in different fields and contexts. Thus, the paradigm on the production and the consumption of the image has been changed and recycled rapidly. The relation between the production and the consumption of the image also has changed accordingly, allowing quite ambiguous distinction between the producer and the consumer. The transformation through the transfer of the image among different fields opens up a new potential that these reproduced images could be used as an aesthetically expressive tool, rather than merely leaving images to remain royal to its original function as a sign. The thesis is to explore the potential that the topographical lines have beyond its function as a sign age. During the reproduction of the image, the process actively invites the spectator or the consumer to participate in the formation of the image, which promotes a new relation between the producer and the consumer. Instead, the process encourages the consumers to be active producers as well. As a result, the topographical lines do not merely remain as a sign that demarcates the height of the topography, and new images are constantly reproduced from the active participants. This project questions the fixed idea on the sign as a communicative tool, and suggests a new potential for the sign, especially, the topographical lines.

• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.539-556
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• 1995

Periodontal therapeutic modalities should be re-establishing and regenerating the periodontal tissue previously lost to the disease. To achieve periodontal regeneration, periodontal ligament cells must selective migrate to the deneded root surface, attached and proliferated it. Local pH concentration is one of the most factors that periodontal regeneration. The aims of this study were to examine on biological effects of pH to the human periodontal ligament cells in vitro, especially on the cell morphology, attachment, activity, vitality and viability. Human periodontal ligament cells were cultured from extracted tooth for non-periodontal reason. Immediately after extraction, any soft tissue adhering to the cervical parts of the roots was carefully removed with a sterile curette. To produce different pH levels in the media, Eagle's MEM was adjusted from pH 6.6 to 8.2 in 0.2 intervals with 1 M NaOH and 1 N HCl. After cultivation, Then, Periodontal ligament cells were cultured at pH ranging from 6.6-8.2. attachment assay was done at 1, 2 day incubation and activity assay was done at 1, 2, 3 day incubation. The experiments were evaluated by scaning electron microscopic techniques (HITACHIX-650 Scaning Electron Microanalyzer, Tokyo, Japan), MTT assay, and the cultured periodontal ligament cells were fixed in neutral formalin for 24 hours and immunohistochemically processed by PCNA for proliferating ability. The surviving cells in the medium showed slightly increased volume and widening intercellular distances at low concentration of pH than control group (pH 7.4), and apparently shrinkage at high concentration of pH than control group (pH 7.4). The results of the statistical analysis from the experiment on attachment, vitality and viability were as follows. Attachment of periodontal ligament cells at 1st and 2nd day, similar attachment rate of low concentration pH compared with control value (pH 7.4). But above pH 8.0, attachment rate were statistically significant decrease from control value(P<0.05). Periodontal ligament cell's activities were maximum at pH 7.6 by MTT assay. Similar with control value at low concentration of pH. But, the activities were statistically significant decrease at high concentraration of pH(P<0.05). Cellular proliferating rate (PCNA index) were statistically significant decrease from control value at low and high concentration of pH(p<0.05). This results suggested that hjgh concentration pH, in other words, alkali pH was cytotoxic effects on human periodontal ligament cells in vitro.