• KIISE Transactions on Computing Practices
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• v.23 no.4
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• pp.238-243
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• 2017

This paper presents a study regarding a systemic structure that forms a link between heterogeneous terminals and the WebRTC (Web real-time communication) based video-conferencing systems. This system consists of a WebRTC-based terminal, a signal server for the relaying of the necessary signals for media negotiations, an MCU provides an interworking interface for the heterogeneous terminal, and the heterogeneous terminals that interwork with the MCU. This technology enables the interoperability between the WebRTC-based video-conferencing solutions and the legacy devices. In addition to reducing the replacement costs regarding new-technology-based solutions, the existing legacy equipment enables the use of multiparty-conference, thereby increasing the use ability of the conferencing systems.

• The Journal of the Korea Contents Association
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• v.11 no.4
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• pp.83-91
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• 2011

The roadmap DB update for unknown roads is a very important factor for car navigation systems. In this paper, we propose a cloud computing based roadmap generation method for use between heterogeneous navigation system for unknown roads. While the drivers drive on unknown roads, the proposed method extracts the road attribute information, and then generates the metadata in an XML format that is available for the heterogeneous navigation systems in a cloud environment. The metadata is proposed to be used as a replacement for conventional proprietary roadmap formats which used by roadmap providers, which is efficient for heterogeneous navigation system providers in a cloud computing environment. Then, this metadata is provided to the roadmap DB providers through the cloud computing interfaces. With the proposed method, the roadmap DB providers update the own roadmap DB for navigation systems in real time. Therefore, the proposed method can reduce the costs of an actual traveling test and the maintenance for the roadmap DB provides. Thus, the cloud-oriented road map generation method can more efficiently update the unknown road information.

• Proceedings of the Korea Contents Association Conference
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• 2003.11a
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• pp.234-244
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• 2003

In distributed file-systems, cooperative caching algorithm which owns the data cached at each node jointly is used to reduce an expense of disk access. Cooperative caching algorithm is the method that increases a cache hit-ratio and decrease a disk access as it holds the cache information of distributed systems in common and makes cache larger virtually. Recently, several cooperative caching algorithms decrease the message costs by using approximate information of the cache and increase the cache hit-ratio by using local and global cache fields dynamically. And they have an advantage that increases the whole field hit-ratio by sending a replaced block to the idel node on cache replacement in order to maintain the replaced block in the cache field. However the wrong approximate information deteriorates the performance, the concistency maintenance goes to great expense to exchange messeges and the cost that manages Age-information of each node to choose the idle node increases. In this thesis, we propose a cooperative cache algorithm that maintains correct cache information, minimizes the maintance cost for consistency and the management cost for cache Age-information. Also, we show the superiority of our algorithm through the performance evaluation.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.6
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• pp.637-644
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• 2010

The purpose of this study is to analyze characteristics of water quality factor scientifically and develop the multiple regression model predicting dissolved oxygen to save periodic replacement costs for dissolved oxygen sensor. Correlation analysis using the environmental data obtained from 2 different land-based fish farms of the Geogeum-do, Geheung-gun coastal area during the periods from November 2008 to January 2009 shows that water temperature was negatively correlated with dissolved oxygen and pH butpH was positively correlated with salinity and dissolved oxygen. The information of Keumho fish farm in 2009 is presented by the tables which are monthly statistics of water quality factors and seasonable difference by the Duncan's post-test. Also we developed multiple regression model predicting dissolved oxygen, the usefulness of which was verified by the comparison graph between estimates and actual observations. The developed regression model shows that seawater temperature and salinity give negative affect to dissolved oxygen while pH gives positive affect to it. Lastly the seawater temperature has much higher explanatory power than pH factor.

• Computers and Concrete
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• v.19 no.5
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• pp.489-499
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• 2017

Self-Compacting Concrete (SCC) is a new technology capable to flow without segregation or any addition of energy which leads to efficient construction and cost savings. In this study, the effect of replacing the Ordinary Portland Cement (OPC) with Fly Ash (FA) on the strength, durability of the concrete was investigated experimentally, and carbon footprint and cost were also assessed. Four different replacement FA ratios (0%, 20%, 40% and 60%) were used to create four SCC mixes. Standard test methods were used to determine the workability, strength, and durability of the SCC mixes including resist chloride ion penetration, water permeability, water absorption, and initial surface absorption. The axial cube compressive strength tests were performed on the SCC mixes at 1, 7, 14, 28 and 35 days. Replacing the OPC with FA had a significant positive impact on chloride iron penetration resistance and water absorption but had a considerable negative impact on the compressive strength. The SCC mix with 60% FA had 36.7% and 15.8% enhancement in the resistance to chloride ion penetration and water absorption, respectively. Evaluation of the carbon footprint and the cost of each SCC mixes showed the $CO_2$ emissions mixes 1, 2, 3 and 4 were significantly reduced by increasing the FA content from 0% to 60%. Compared with the control mix, the cost of all mixes increased when the FA content increased, but no significant differences were seen between the estimated costs of all four mixes.

• Design & Manufacturing
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• v.1 no.1
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• pp.7-11
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• 2007

The fabrication of precision optical components by deterministic CNC grinding is an area of great current interest. Replacement of the traditional, craftsman driven, optical fabrication process is essential to reduce costs and increase process flexibility and reliability. Moreover, CNC grinding is well suited to the fabrication of complex shapes such as aspheres, making it possible to design optical systems with fewer components and reduced weight. Current technology is capable of producing surfaces with less than 2 microns peak to valley error, 50 nm rms surface roughness, and less than 1 micron subsurface damage. Bound abrasive tools, in which the abrasive particles are fixed in a second (matrix) material, play an important part in achieving this performance. In this paper, the factors affecting the ultra-fine surface roughness and profile accuracy of machined surfaces of aspheric parts has been analyzed experimentally and theoretically and on ultra-precision aspheric grinding system and precise adjusting mechanism have been designed and manufactured. In the paper we report the results of experiments and modeling performed to examine the effects of machinability, occurring during grinding of optical surfaces, on the tool surface profile. Profiles of machined surface were measured by using SEM. In order to optimize grinding conditions of aspheric lens processing, we performed experiments by design of experiments.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.8
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• pp.1158-1164
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• 2003

In two feeding experiments male and mixed-sex broiler chicks were offered diets based on sorghum and a wheatsorghum blend with two tiers of nutrient specifications, without and with microbial phytase (600 and 800 FTU/kg), from 7-25 and 1-42 days post-hatch, respectively. The nutrient specifications for protein, amino acids, energy density and phosphorus (P) of standard diets were reduced to formulate the modified diets on a least-cost basis. Calculated differences in nutrient specifications between standard and modified diets ranged from 14.3 to 17.1 g/kg crude protein, 0.24 to 0.40 MJ/kg apparent metabolisable energy (AME) and 1.06 to 1.20 g/kg available P. In both experiments, reduced nutrient specifications had a negative impact on growth rates and feed efficiency and phytase supplementation had a positive influence on growth performance and protein efficiency ratios (PER). Phytase addition to the less expensive, modified diets either partially or entirely compensated for reduced growth performance and, consequently, feed costs per kg of live weight gain were reduced. In Experiment 1, phytase increased (p<0.001) nitrogen-corrected AME (AMEn) from 15.39 to 15.89 MJ/kg dry matter. For nitrogen (N) retention there was an interaction (p<0.05) between diet type and phytase as the effects of phytase on N retention were more pronounced in the modified diets, with an increase from 0.512 to 0.561. These results demonstrate the positive effects of phytase on protein and energy utilisation, in addition to its established liberation of phytate-bound P and illustrate the feasibility of assigning nutrient replacement values to the feed enzyme for consideration in least-cost ration formulations. Further work is, however, required to define the most appropriate reductions in nutrient specifications in association with phytase supplementation.

• Survey Research
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• v.4 no.1
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• pp.1-29
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• 2003

Telephone surveys miss, among other people, those who live in homes without telephones, people who are away from home at the time of interview and people who refuse to be interviewed. Recently, mobile phone survey has emerged as “A replacement technology” to the old telephone survey method. Mobile survey enables us to do many things we could not do or could not afford to do before, and reatly enhance the efficiency if the opinion surveys. Very specifically, the mobile survey enables us to control respondent's accessability, interviewer bias and to do incredibly fast and at a affordable costs. The authors analyze the results of mobile-phone local election polls and ELSI bio-technology attitude survey. The authors describe their results, the methods they used, including the use of demographic and propensity weighting to correct for substantial biases in the raw, unweighted data. The results show that mobile survey can predict the election outcomes with approximately equal accuracy to that of the telephone poll after weighting. This paper also cautions readers not to assume that mobile survey can be used with equal success in other elections and emphasizes the need for continuing research to improve mobile survey methods in the future.

• Journal of Animal Science and Technology
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• v.47 no.2
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• pp.221-232
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• 2005

This study was carried out to investigate the effect of replacing fish meal or soybean meal with feather meal or bromelain treated feather meal in broiler diets on the performances and nutrient utilization. Two hundred and twenty-five broilers were randomly allotted to five dietary treatrnents((1) control, basal diet; (2) PFM 50, 50 % of the fish meal replaced with bromelain treated feather meal; (3) PFM 100, 100% of the fish meal replaced with bromelain treated feather meal; (4) PSM 20, 20 % of the soybean meal replaced with bromelain treated feather meal; and (5) PSM 40, 40% of the soybean meal replaced with bromelain treated feather meal) in a 5-week feeding trial. In the overall period, body weight gain of the PFM 50(1,807 g), PSM 20(1,816 g) and PSM 40(1,823 g) were the highest and that of the PFM 100 was 1,744 g. The body weight gain of the control(1,698 g) was the lowest(p < 0.05) among treatments. Feed conversion was significantly(p< 0.05) improved when bromelain treated feather meal replaced 20% of the fish meal in the basal diet. Digestibilities of dry matter, ether extract, organic matter and phosphorus were not different among the treatments. Digestibility of crude protein of PFM 50(65.87 %), PSM 20(67.18 %) and PSM 40(67.56%) were the highest, and that of the control(54.49%) was the lowest(p < 0.05) among treatments. Arrunonia and hydrogen sulfide gases from the feces were significantly(p < 0.05) decreased in chicks fed the PFM 50, PSM 20 and GFM 40 diets, when observed after 3 weeks of feeding trials. Feed costs of the control and PFM 50 were 604 and 629 won, respectively but that of PSM 50 was 820 won. Therefore, replacement of fish meal with bromelain treated feather meal in the diets for chicks could be useful for economic production.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.212-212
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• 2011

In addition to the catalysts' activity and selectivity, the deactivation of catalysts during use is of practical importance. It is crucial to understand the phenomena of the deactivation to predict the loss of activity during catalyst usage so that the high operational costs associated with catalyst replacement can be reduced. In this study, the activity of Ru catalysts, such as nanoparticles (3~6 nm) and polycrystalline thin film (50 nm), have been investigated under CO oxidation and oxidative/reductive reaction conditions at various temperatures with the ambient pressure X-Ray photoelectron spectroscopy (APXPS). With APXPS, the surface oxides on the catalyst are measured and monitored in-situ. It was found that the Ru film exhibited faster oxidation-and-reduction compared to that of nanoparticles showing mild oxidative-and-reductive characteristics. Additionally, the larger Ru nanoparticles showed a higher degree of oxide formation at all temperatures, suggesting a higher stability of the oxide. These observations are in agreement with the catalytic activity of Ru catalysts. The loss of activity of Ru films is correlated with bulk oxide formation, which is inactive in CO oxidation. The Ru nanoparticle, however, does not exhibit deactivation under similar conditions, suggesting that its surface is covered with a highly active ultrathin surface oxide. Since the active oxide is more stable as nanoparticles than as a film, the nanoparticles showed mild oxidative/reductive behavior, as confirmed by APXPS results. We believe these simultaneous observations of both the surface oxide of Ru catalysts and the reactivity in real time enable us to pinpoint the deactivation phenomena more precisely and help in designing more efficient and stable catalytic systems.