• Journal of Korea Water Resources Association
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• v.33 no.5
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• pp.581-592
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• 2000

Turbulence structure and suspended sediment transport capacity in vegetated open-channel flows are investigated numerically in the present paper. The $\textsc{k}-\;\varepsilon$ model is employed for the turbulence closure. Mean velocity and turbulence characteristics including turbulence intensity, Reynolds stress, and production and dissipation of turbulence kinetic energy are evaluated and compared with measurement data available in the literature. The numerical results show that mean velocity is diminished due to the drag provided by vegetation, which results in the reduction of turbulence intensity and Reynolds stress. For submerged vegetation, the shear at the top of vegetation dominates turbulence production, and the turbulence production within vegetation is characterized by wakes. For emergent condition, it is observed that the turbulence generation is dominated by wakes within vegetation. In general, simulated profiles compares favorably to measured data. Computed values of eddy viscosity are used to solve the conservation equation for suspended sediment, yielding sediment concentration more uniform over the depth compared with the one in the plain channel. The simulation reveals that the suspended load decreases as the vegetation density increases and the suspended load increases as the particle diameter decreases for the same vegetation density.

• Journal of Broadcast Engineering
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• v.10 no.4 s.29
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• pp.528-539
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• 2005

The H.264 has been adopted as the video codec for various multimedia services such as DMB and next-generation DVD because of its superior coding performance. However, the reference codec of the standard, the joint model (JM) contains quite a few algorithms which are too complex to be used for the resource-constraint embedded environment. This paper introduces very low-complexity H.264 encoding algorithm which is applicable for the embedded environment. The proposed algorithm was realized by restricting some coding tools on the basis that it should not cause too severe degradation of RD-performance and adding a few early termination and bypass conditions during the motion estimation and mode decision process. In case of encoding of 7.5fps QCIF sequence with 64kbpswith the proposed algorithm, the encoder yields worse PSNRs by 0.4 dB than the standard JM, but requires only $15\%$ of computational complexity and lowers the required memory and power consumption drastically. By porting the proposed H.264 codec into the PDA with Intel PXA255 Processor, we verified the feasibility of the H.264 based MMS(Multimedia Messaging Service) on PDA.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.2
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• pp.154-160
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• 2000

Landfill gas (LFG) utilization in old landfill was estimated using LFG models. The results showed that Scholl Canyon model best described the LFG generation. LFG was extracted more than the amount of natural production which caused air inflow from outside that resulted in dilution of methane concentration and increase of oxygen concentration. It was negative for the LFG utilization. Therefore, to use LFG, the plan of stabilization by LFG extraction should be ineffective. The use of LFG will have no problem if LFG is extracted less than the amount of natural production which was estimated based on modeling. At 8 years elapsed from landfill, now, the amount of natural landfill gas production was decreased sharply. The plan for using LFG from old landfill is feasible if LFG is used for the less than the amount of natural production as a small scale even though for the aspect of efficiency, it was less economic than use of LFG just after closing landfilling and it was helpful for stabilization of landfill by LFG extraction.

• The Journal of the Korea Contents Association
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• v.17 no.2
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• pp.521-534
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• 2017

In 2013 the Netflix, an OTT in USA, launched all at once 13 episodes of the House of Cards season. Binge-watching is the word which means watching continuously 2~6 episodes of a TV program with one sitting, the new normal of TV watching behavior, cultural and social currents all over the world. This study has analyzed the factors and motivations which affect to the persistent intention to use binge-watching. It conducted an online survey from 333 Quota sample from Korean age groups between 20th~60th with 81 questionnaires. The 5 groups were induced as motivation factors to binge-watching. The 3 groups which consisted of , , are affecting as positive to intention to use binge-watching. But the other 2 groups which are and doing as negative. The survey has shown that the persistent intention to binge-watching is affected by ages more younger, whom doing binge watching more frequently, whom estimating more higher to the conceived usefulness to use. As a theoretical model, expanded technology acceptance model was adopted and US drama House of Cards. This study could promote the next generation contents planning and S-VOD service industry.

• Journal of Distribution Science
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• v.13 no.2
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• pp.105-112
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• 2015

Purpose - There is a recent social trend that is focused on the revitalization of business-founding. Business-founding now has an important impact on the progress of the national economy because of youth unemployment and an increase in baby-boom generation retirees. However, the support and infrastructure required for business-founding of the disabled are very insufficient. Since most supporting policies are on youth or middle-aged business-founding, business-founding by the disabled and the socially weak is losing competitiveness. Accordingly, this study diagnosed the issues by analyzing the current status of business-founding by the disabled and suggested a fostering direction for the advance of business-founding by the disabled. An idea for the founding of various business items is required for the competitiveness of business-founding by the disabled and the establishment of a growth-model based on marketing is required so that business-founding by the disabled would advance toward commercialization with growth potential. Research design, data, and methodology - Regarding the study method, the existing study literature on the status and issues in business-founding was mainly explored. In addition, the existing literature on the status and issues in business-founding by the disabled was also studied. The support on business-founding by the disabled by policy enforced by the 'Welfare Service Agency for the Disabled'and the support of related agencies including financial support on the commercialization of business-founding by the disabled were also examined. Results - Existing studies on business-founding by the disabled are very insufficient. It is very difficult to study a viable business-founding by the disabled fostering policy without thorough learning on the difficulties of business-founding by the disabled. Therefore, this study suggested a direction for the resolution of various issues such as market, funds, item, operational matters, and service by analyzing the difficulties in business-founding by the disabled until now. Particularly, this study suggested that building a commercialization model from the aspect of marketing strategy and the effort to change the growth aspect of the disabled into competitiveness are essential. Conclusions - This study examined the aspect of developing an item-development process for the growth and founding of disabled-owned businesses and the requirement of a government support system by multiple policies. Since the number of studies on business-founding by the disabled is very small, it is expected that this study would become an important study in the field of business-founding by the disabled. The revitalization of business-founding by the disabled substantially contributes to the progress of the state of the economy and continuous interest is required from the viewpoint of equal advance in the society. Success models in business-founding by the disabled should be created continuously and active publicizing of them to the disabled business-founders by analyzing the success cases would also be required. In addition, it is believed that a market entry strategy by way of a win-win strategy and cooperative relation with big companies should be also developed in the future.

• Journal of the Korean association of regional geographers
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• v.1 no.1
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• pp.1-21
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• 1995

We Korean geographers have been interesting merely in research trends and models which induced in more advanced societies. We unconcerned with the models were painfully acquired through many field surveys and accumulated researches. Approaches to the generalization without accumulating experienced studies are just like 'building on the sand' and 'it is nothing but the paper'. We still need many field surveys, regional approaches and very basic researches for induced the Korean geographic models. In geography. 'where' is not main goal. 'Why and how' are the most important. We know these very much. But we do not recognize that 'what is where' in Korea, still now. We must have our own Korean spatial models. But geography is not build in a day and in one generation. It needs interdisciplinary or system approaches accompany with the other fields of sciences. We concern with the spatial principles and laws which were hidden by the complicated phenomena in real world.

• Journal of KIISE:Software and Applications
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• v.37 no.4
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• pp.323-339
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• 2010

The complexity of embedded systems and the effort to develop them has been rising in proportion with their importance. Also, the heterogeneity of the hardware and software parts in embedded systems makes it more challenging to develop. Errors caused by hardware/software interfaces, especially, account for up to 13 percent of failures with an increasing trend. Therefore, verifying the interface between hardware and software in embedded system is one of the most important research areas. However, current approaches such as co-simulation method and model checking have explicit limitations. In this paper, we propose the synthesizable interface co-verification framework for hardware/software co-design. Firstly, we introduce the separate interface specifications for the heterogeneous components to describe hardware design and software design. Our specifications are expressive enough to describe both. We also provide the transformation rules from the software specification to the hardware specification so that the whole system can be described from the software view. Secondly, we address the solution of verifying the interface of the software and hardware design by adopting and extending existing verification-techniques and extending them. In hardware interface verification, we exploit the model checking technique and provide more efficient verification by closing the hardware design from the assumption of the software behavior which is ensured by software verification step. Lastly, we generate the interface codes such as device APIs, device driver, and device controller from the specification so that verified hardware and software codes can be synthesized without extra efforts.

• Journal of Korea Water Resources Association
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• v.47 no.10
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• pp.921-934
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• 2014

The purpose of the study is to derive a long term reservoir operation method that is easy to understand and apply to practical use for dam operators. The zone based operation rule is a simple method to make operation decisions by criteria corresponding to storage zones. The reservoir storage levels dividing a reservoir, however, must be determined by some methods. We developed a reservoir operation model based on the zone based operation rule and the shuffled complex evolution algorithm (SCE-UA) was used to determine storage levels for zone division. The model was applied to Angat Dam in the Philippines that has trouble in water supply due to imbalance between supply and demand. We derived a zone based operation rule for Angat Dam and applied it to the reservoir simulation of Angat Dam using the historical inflow. The simulation results showed water supply deficit and power generation were improved by 34.5% and 21.2%, respectively, when compared with the historical records. The current study results may be used to derive a long term reservoir operation rule.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.1
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• pp.65-74
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• 2020

The purpose of this study was to investigate the physical characteristics of marine environment, and to predict the probability of the occurrence of hypoxia in the Dangdong bay. We predicted hypoxia using the logistic regression model analysis by observing the water temperature, salinity, and dissolved oxygen concentration. The analysis showed that the Brunt-Väisälä frequency which was shallow than the deep bay entrance, was higher inside the bay due to a lesser amount of fresh water inflow from the inner side of the bay, and density stratification was formed. The Richardson number, and Brunt-Väisälä frequency were very high occasionally from June to September; however, after September 2, the stratification had a tendency to decrease. Analysis of dissolved oxygen, water temperature, and salinity data observed in Dangdong bay showed that the dissolved oxygen concentration in the bottom layer was mostly affected by the temperature difference (dt) between the surface layer and bottom layer. Meanwhile, when the depth difference (dz) was set as a fixed variable, the probability of the occurrence of hypoxia varied with respect to the difference in water temperature. The depth difference (dz) was calculated to be 5 m, 10 m, 15 m, 20 m, and the difference in water temperature (dt) was found to be greater than 70 % at 8℃, 7℃, 5℃, and 3℃. This indicated that the larger the difference in depth in the bay, the smaller is the temperature difference required for the generation of hypoxia. In particular, the place in the bay, where the water depth dif erence was approximately 20 m, was found to generate hypoxia.

• Journal of the Korean Association of Geographic Information Studies
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• v.2 no.3
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• pp.91-100
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• 1999

To extract value-added products from satellite images for the benefit of science and human life, the Satellite Technology Research Center at Korea Advanced Institute of Science and Technology has developed an integrated software 'Valadd-Pro'. In this paper, the 'Valadd-Pro' software is briefly introduced and its main components such as geometric correction, ortho correction and digital elevation model extraction are described. The performances of the 'Valadd-Pro' was assessed on $60km{\times}60km$ SPOT panchromatic images using ground control points from GPS measurements. Also, the height accuracy was measured by comparing our results with the $DTEDs^3$ produced by USGS and the DEM generated from the digitized countours of maps produced by the National Geographic Institute. In geometric correction, the 'Valadd-Pro' software needed fewer ground control points than a commercial software 'P' for the satisfactory results. In ortho correction, the 'Valadd-Pro' software show the similar performance to a commercial software 'P'. In digital elevation model extraction, the 'Valadd-Pro' software is two times more accurate and four times faster than a commercial software 'P'.