• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권8호
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• pp.3121-3135
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• 2015

Owing to the increase in consumption of multimedia content and the improvement of device capacity, user demand for high-quality content has increased. However, it is difficult to transport such large amounts of content over the existing broadcasting network with limited bandwidth. To provide high-definition broadcasting, some studies suggest methods of transporting multimedia over heterogeneous networks after encoding content hierarchically. MPEG Media Transport (MMT), standardized by Moving Picture Experts Group (MPEG), is a solution that enables large-volume media transport over heterogeneous networks such as digital broadcasting networks and packet-switched networks. In the case of delivering a scalable encoded video over different networks, synchronization of each stream is an important issue. MMT defines a synchronization scheme, but does not contain sufficient functions to implement it. In this paper, we propose a synchronization scheme for media streams that are encoded hierarchically, divided into layers, and transported over heterogeneous networks. We implement our scheme using MMT and HTTP, and experimented using three encapsulated video streams with different durations. As a result, we show that the proposed scheme can reduce the waiting time to display high-quality video, relative to Dynamic Adaptive Streaming over HTTP-Scalable Video Coding (DASH-SVC) by requesting segments of enhanced layers after calculating the transmission time. Additionally, we find out that the selection of durations have a relation to the characteristics of the video.

• Environmental Engineering Research
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• 제14권1호
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• pp.53-60
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• 2009

The main objective was to develop and assess a dynamic fate and transport model for lead in air, soil, sediment, water and vegetation. Daejeon was chosen as the study area for its relatively high contamination and emission levels. The model was assessed by comparing model predictions with measured concentrations in multi-media and atmospheric deposition flux. Given a lead concentration in air, the model could predict the concentrations in water and soil within a factor of five. Sensitivity analysis indicated that effective compartment volumes, rain intensity, scavenging ratio, run off, and foliar uptake were critical to accurate model prediction. Important implications include that restriction of air emission may be necessary in the future to protect the soil quality objective as the contamination level in soil is predicted to steadily increase at the present emission level and that direct discharge of lead into the water body was insignificant as compared to atmospheric deposition fluxes. The results strongly indicated that atmospheric emission governs the quality of the whole environment. Use of the model developed in this study would provide quantitative and integrated understanding of the cross-media characteristics and assessment of the relationships of the contamination levels among the multi-media environment.

• 한국대기환경학회지
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• 제29권4호
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• pp.407-438
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• 2013

Current status and future direction of air quality modeling for monitoring and forecasting air quality in East Asia were discussed in this paper. An integrated air quality modeling system, combining (1) emission processing and modeling, (2) meteorological model simulation, (3) chemistry-transport model (CTM) simulation, (4) ground-based and satellite-retrieved observations, and (5) data assimilation, was introduced. Also, the strategies for future development of the integrated air quality modeling system in East Asia was discussed in this paper. In particular, it was emphasized that the successful use and development of the air quality modeling system should depend on the active applications of the data sets from incumbent and upcoming LEO/GEO (Low Earth Orbit/Geostationary Earth Orbit) satellites. This is particularly true, since Korea government successfully launched Geostationary Ocean Color Imager (GOCI) in June, 2010 and has another plan to launch Geostationary Environmental Monitoring Spectrometer (GEMS) in 2018, in order to monitor the air quality and emissions in/around the Korean peninsula as well as over East Asia.

• Carbon letters
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• 제14권3호
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• pp.162-170
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• 2013

The performance of graphene-based electronic devices is critically affected by the quality of the graphene-metal contact. The understanding of graphene-metal is therefore critical for the successful development of graphene-based electronic devices, especially field-effect-transistors. Here, we provide a review of the peculiar properties of graphene-metal contacts, including work function pinning, the charge transport mechanism, the impact of the process on the contract resistance, and other factors.

• 한국대기환경학회지
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• 제26권1호
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• pp.34-47
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• 2010

Long-range transport of air pollutants was simulated using Comprehensive Acid Deposition Model (CADM) and Yonsei University-Sulfuric Acid Deposition Model (YU-SADM). For the simulation, weather patterns that represent the four seasons were derived through a clustering analysis with 5-years of meteorological data. The simulation result showed that in spring, influenced by strong low pressure from China, air pollutants of moved to the Korean Peninsula. In summer, humid air moved into the Korean Peninsula across the Yellow Sea while the north pacific high pressure extended, making the concentration of air pollutants lower than that in the other seasons. In autumn, air pollutants were transported by the northwest wind caused by the movement of high pressure over the Yellow Sea, while in winter air pollutants were influenced by northwest winds from continental highs. The amount of air pollutants in each season showed that high amount of pollutants were transported in winter due to the strong northwest wind. The in-flows were 3 to 8 times higher than those of the other seasons, and out-flows were about as twice as high. The amount of wet deposition in summer and autumn increased significantly compared to the amount in the other seasons due to the increase of rainfall. Source-receptor relationship analysis for sulfur showed that 70 to 91 precent of the total deposition came from the self-contribution by the Korean Peninsula. In winter, contribution from China was about 25 percent of the total deposition which was higher amount than any other season.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1998년도 PROCEEDINGS OF THE 14TH KACG TECHNICAL MEETING AND THE 5TH KOREA-JAPAN EMGS (ELECTRONIC MATERIALS GROWTH SYMPOSIUM)
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• pp.29-33
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• 1998

Transport phenomena paly an inmportant role in bulk crystal growth processes. During crystal growth, the control of the growth front and the dopant concentration is crucial to crystal quality. The growth feasibility in thus determined by the heat transfer controlling the interface convexity and by the mass transfer controlling the constitutional supercooling. Through numerical modeling, a thorough understanding of the growth processes is possible, which in turn is a key to process improvenment. In this paper, we will summarize some work dine in my laboratory, both numerical and experimental, to illustrate the importance of understanding the transport phenomena during crystal growth processes.

• Advances in environmental research
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• 제4권2호
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• pp.105-117
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• 2015

The groundwater is a very important part of the environment and must be protected for the benefit of the present and future generation. The contamination of soil and groundwater by chemicals has become an increasing concern in the recent past. These chemicals enter the groundwater system by a wide variety of mechanisms, including accidental spills, land disposal of domestic and industrial wastes and application of agricultural fertilizers. Once introduced into an aquifer, these contaminants will be transported by flowing groundwater and may degrade water quality at nearby wells and streams. For improving the management and protection of groundwater resources, it is important to first understand the various processes that control the transport of contaminants in groundwater. Predictions of the fate of groundwater contaminants can be made to assess the effect of these chemicals on local water resources and to evaluate the effectiveness of remedial actions. In this study, an attempt has been made to investigate the behaviour of solute transport through porous media using laboratory experiments. Sodium chloride was used as a conservative chemical in the experiment. During the experiment, pulse boundary condition and continuous boundary conditions were used. Experimental results have been presented for conservative solute transport in the sand. The pattern of the break through curve remains almost same in all the cases of varying flow rate and initial concentration of conservative chemical.

• Asian-Australasian Journal of Animal Sciences
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• 제20권3호
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• pp.424-431
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• 2007

The aim of this study was to determine the effects of short road transportation in an open truck during hot season on live weight shrink, physiological responses, and carcass and meat quality of Omani sheep at 6 and 12 months of age. Thirty-six male sheep, 18 of each age group, were used. Age groups were assigned randomly to transported and not-transported groups. The transported group was transported to the slaughterhouse the day of slaughter in an open truck covering a distance of approximately 100 km. The average temperature during transportation was $37^{\circ}C$. The not-transported group was kept in a lairage of a commercial slaughterhouse with ad libitum feed and water for 48 h prior to slaughter. Blood samples were collected from sheep before loading and prior to slaughter via jugular venipuncture to assess their physiological response to transport in relation to hormonal levels. Animals were weighed just before loading onto a truck and after transport to assess shrinkage. Muscle ultimate pH, expressed juice, cooking loss percentage, WB-shear force value, sarcomere length and colour L*, a*, b* were measured on samples from longissimus dorsi, biceps femoris and semitendinosus muscles collected at 24 h postmortem at $1-3^{\circ}C$. Live weight shrinkage losses were 1.09 and 1.52 kg for 6 and 12 month transported sheep, respectively. The transported sheep had significantly (p<0.05) higher cortisol, adrenaline, noradrenaline, and dopamine concentration levels prior to slaughter at both ages than the not-transported sheep. Transportation significantly influenced meat quality characteristics of three muscles. Muscle ultimate pH and shear force values were significantly higher, while CIE L*, a*, b*, expressed juice and cooking loss were lower in transported than not-transported sheep. Age had a significant effect on meat quality characteristics of Omani sheep. These results indicated that short-term pre-slaughter transport at high ambient temperatures can cause noticeable changes in physiological and muscle metabolism responses in sheep.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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• pp.645-654
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• 2021

This research aims to examine the influence of road transportation infrastructure on the mobility of goods transport and the regional economy in Langkat Regency in Indonesia. This type of research is an associative and explanatory research whose data is obtained through a questionnaire survey. This study took a sample of 305 respondents using probability sampling in Langkat Regency, North Sumatera, Indonesia. Data analysis techniques use path analysis. The research results showed that the road transportation infrastructure variables had a significant and positive effect on the mobility of goods transport. Road transportation infrastructure and freight mobility simultaneously have a significant and positive effect on the economy of Langkat Regency. Road transportation infrastructure with the dimensions of road accessibility and maintenance partially directly has a significant and positive effect on the economy of the Langkat Regency. Road transportation infrastructure with the dimensions of road design and road construction quality partially does not have a direct effect on the regional economy, but has a positive and significant effect through the mobility of freight transport. The mobility of goods transport becomes an intervening variable that acts to mediate or determine the relationship between road transportation infrastructure variables to the regional economy.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.528-533
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• 2005

The last decades railroad transport has lost market share to cars, trucks and airplanes. Rail companies could not compete in flexibility, speed, cost and quality. The new technology developments of rail transport are focused on high speed. But not all technology is easily transferable from one society to another, if for no other reasons than those attributable to differences in economic, demographic, and geographic factors. This case study is focused on the technological transfer process and items of Korea's high speed rail system and also compares with the Japanese Shinkansen and German ICE.