• The Korean Journal of Petroleum Geology
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• v.9 no.1_2 s.10
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• pp.16-23
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• 2001

The study area in the East Sea is located on the northeastern margins of the Ulleung Basin near the Kita-Yamato Bank. The research area provides the important clue to the development of Miocene basins which are characterized by the normal faults and volcanic activities related to rifting in the continental crust. Kita-Yamato Bank is a small sediment-filled graben which was formed by failed rifting in the Early Miocene. The basins rapidly vary the bathymetry, depth of acoustic basement and thickness of sedimentary layer. The tension in the study area caused the extensional lithospheric deformation before/during the Early Miocene. In consequence, tectonic forces resulted in the depression or subsidence of basement from continental rifting in the Kita-Yamato Bank followed by the opening of the Ulleung Basin, and caused the onset of graben or half-graben structure bounded by large blocked syn-rift faults. Afterward no significant tectonic deformation exists, with the consequence that post-rift normal faults with small heave were formed and reactivated by the resultant forces such as tectonic subsidence, sediment loading and volcanic activity. The Cenozoic sediment layer has a maximum thickness of 1.0 s along the center of the graben or half-graben, which overlies the consolidated acoustic basement. Seismic units V and IV supposed to be syn-rift sedimentary rocks are deformed by both the volcanic activities and numerous basement-involved normal faults induced from extension. In the uppermost layer, slump scars resulted from the slope failure are recognized.

• Korean journal of communication and information
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• v.35
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• pp.114-146
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• 2006

Now, Korea-U.S.A Free Trade Agreement talk is underway in Korea. In FTA talks, the issues on audio-visual sector including screen quota, opening of broadcasting and telecommunication to the U.S.A. are becoming a hot potato. Globalization has been speed up by mass media and telecommunications. Cultures are no longer bounded by specific place but, through the migration of persons and the electronic flows of information, ideas and images, transgress established boundaries. So issues and debates have to be focused on global culture and cultural imperialism. Some would argue global culture is the consequences of capitalist world-system, so dominance by the center should be criticized and vanished. Some would say that global culture would help recipient society's people with cultural diversify and improvement. The issues on culture and communication, particularly at international level call for our attention in light of cultural identity, homogenization and diversity. Although I criticize the cultural imperialism thesis, I suggest critical acceptance of cultural imperialism. That is the observation of complexity between internal and external dynamics. The process of cultural imperialism is not simple and unitary. It rather involves the various forces of internal dynamics along with external forces.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1999.12a
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• pp.121-129
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• 1999

When continuous media are transmitted over the communication networks, asynchrony which can not maintain temporal relationships among packets may occur due to a random transit delay. There exist two types of synchronization schemes ; for guaranteed or non-guaranteed resource networks. The former which applies a resource reservation technique maintains delay characteristics, however, the latter supply a best-effort service. In this paper, I propose a intra-media synchronization scheme to transmit continuous media on general networks not guaranteeing a bounded delay tome. The scheme controls transmission times of the packets by estimating next delay time with the delay distribution. So, the arriving packets may be maintained within a limited delay boundary, and playout will be performed after buffering to smoothen small delay variations. The continually increasing delay due to network overload causes buffer underflow at the receiver. To solve it, the transmitter is required to speed up instantaneously. Too much increase of transmission-rate may cause network congestion. At that time, the transmitter drops the current packet when informed excessive delay from the receiver.

• Journal of Educational Research in Mathematics
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• v.20 no.1
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• pp.85-102
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• 2010

Linear programming(LP) is useful for finding the best way in a given condition for some list of requirements represented as linear equations. This study analysed LP in mathematics contexts and LP in school mathematics contexts, considered learning process of LP from an epistemological point of view, and explored a hypothetical learning trajectory of LP. The differences between mathematics contexts and school mathematics contexts are whether they considered that the convex polytope $\Omega$ is feasible/infeasible or bounded/unbounded or not, and whether they prove the theorem that the optimum is always attained at a vertex of the polyhedronor not. And there is a possibility that students could not understand what is maximum and minimum of a linear function when the domain of the function is limited. By considering these three aspects, we constructed hypothetical learning trajectory consisted of 4 steps. The first step is to see a given linear expression as linear function, the second step is to partition a given domain by straight lines, the third step is to construct the conception of y-intercept by relating lines and the range of k, and the forth step is to identify whether there exists the optimum in a given domain or not.

• Journal of Environmental Science International
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• v.13 no.8
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• pp.721-731
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• 2004

The dispersion of suspended particulates in the coastal complex terrain of mountain-inland basin (city)-sea, considering their recycling was investigated using three-dimensional non-hydrostatic numerical model and lagrangian particle model (or random walk model). Convective boundary layer under synoptic scale westerly wind is developed with a thickness of about I km over the ground in the west of the mountain, while a thickness of thermal internal boundary layer (TIBL) is only confined to less than 200m along the eastern slope of the mountain, below an easterly sea breeze circulation. At the mid of the eastern slop of the mountain, westerly wind confronts easterly sea breeze, which goes to the height of 1700 m above sea level and is finally eastward return flow toward the sea. At this time, particulates floated from the ground surface of the city to the top of TIBL go along the eastern slope of the mountain in the passage of sea breeze, being away the TIBL and reach near the top of the mountain. Then those particulates disperse eastward below the height of sea-breeze circulation and widely spread out over the coastal sea. Total suspended particulate concentration near the ground surface of the city is very low. On the other hand, nighttime radiative cooling produces a shallow nocturnal surface inversion layer (NSIL) of 200 m thickness over the inland surface, but relatively thin thickness less than 100m is found near the mountain surface. As synoptic scale westerly wind should be intensified under the association of mountain wind along the eastern slope of mountain to inland plain and further combine with land-breeze from inland plain toward sea, resulting in strong wind as internal gravity waves with a hydraulic jump motion bounding up to about 1km upper level in the atmosphere in the west of the city and becoming a eastward return flow. Simultaneously, wind near the eastern coastal side of the city was moderate. Since the downward strong wind penetrated into the city, the particulate matters floated near the top of the mountain in the day also moved down along the eastern slope of the mountain, reaching the. downtown and merging in the ground surface inside the NSIL with a maximum ground level concentration of total suspended particulates (TSP) at 0300 LST. Some of them were bounded up from the ground surface to the 1km upper level and the others were forward to the coastal sea surface, showing their dispersions from the coastal NSIL toward the propagation area of internal gravity waves. On the next day at 0600 LST and 0900 LST, the dispersed particulates into the coastal sea could return to the coastal inland area under the influence of sea breeze and the recycled particulates combine with emitted ones from the ground surface, resulting in relatively high TSP concentration. Later, they float again up to the thermal internal boundary layer, following sea breeze circulation.

• Journal of Navigation and Port Research
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• v.31 no.8
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• pp.689-695
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• 2007

The under developing estuarial port Bupsung is bounded by a river and the sea, and has several well developed tidal lands, where the littoral drift is strong due to the tide and the river discharge. The study area is located at the inner part of a concave bay and has a large tidal range due to the water discharge through the Watan-chun and Junnam-dike. In beginning stage of the ocean physical impact study, the tidal modeling is very important and difficult especially in this area. Moreover, we need a model experiment after the verification of the formulated model based on ocean survey. In this study, we constructed a numerical model to the Bupsung port coastal boundaries, which varies with the past and future development and made simulation with it. The result after development shows that there is a decrease of velocity on flood current and a increase on Ebb current and the minor variation of the tide level, compared with before development.

• The Journal of the Korea Contents Association
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• v.10 no.9
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• pp.68-78
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• 2010

As the IP multicast function is very slowly deployed in Internet due to its scalability problem and inter-domain interoperability problem, interest in the P2P(Peer-to-Peer) streaming technologies for the realtime multimedia multicast applications such as IPTV is highly growing. This paper proposes a P2P streaming method for the QoS-sensitive multimedia multicast applications such as highly-interactive personal IPTV and video conferences. The proposed P2P streaming method allows an application to construct a reliable streaming tree in which a proper number of backup peers are placed according to its reliability requirement. The reliable streaming tree reduces the reconnection delay, occurred in the case of a normal and/or abnormal peer leave, so as to minimize the loss of streaming data. In the proposed P2P streaming method, the join delay of a peer called startup delay is also substantially reduced because the bandwidth and end-to-end delay information of every peer kept in a distributed way allows the target peer for a joining peer to be able to be quickly determined. Moreover, the proposed method's peer admission control mechanism based on the bandwidth and end-to-end delay enables the delay-bounded streaming services to be provided for its corresponding applications.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.9 no.3
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• pp.137-152
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• 2004

The climatological characteristics of coastal zone over the southwestern coast of Korea peninsula were investigated using the data observed by AWS (automatic weather system) and 4 buoy points. Coastal zone is climatologically defined as the region bounded by the distinct contrast of temperature gradient and wind speed across coastline. In the southwest of peninsula four cross-lines consisted of AWS aligned with each buoy were selected as Geojedo buoy line, Geomundo buoy line, Chilbaldo buoy line and Dukjukdo buoy line. Analysis on the diurnal cycle and intra-month variation, monthly mean and maximum value, the temperature gradient with distance between buoy and each station and the accumulative frequency of wind speed were applied to find out the characteristics and the range of coast zone. The maximum ranges of coastal zone vary from offshore to Sanglim (about 34 km distance from coastline) for Geojedo buoy line, to Sunchun (about 52 km) for Geo-mundo buoy line, to Jaeundo (about 27 km) for chilbaldo buoy line and to Yongin (about 65 km) for Dukjukdo buoy line. The modification of coastal zone according to synoptic flow was investigated for the onshore, off-shore and calm cases. The ranges of coastal zone are significantly changed with the distance between 65∼90 km for the case of onshore. In addition, we tried to find out the variation of the wind and temperature and the wind ratio of wind speed at ocean to land stations along Geojedo buoy line during 12∼13 Sep. 2003 affected by typhoon (MAEMI).

• Journal of Korean Society of Transportation
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• v.19 no.5
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• pp.119-134
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• 2001

This paper proposed a dynamic transit vehicle simulation model and a dynamic transit passengers simulation model, which can simultaneously simulate the transit vehicles and passengers traveling on a transit network, and also developed an algorithm of dynamic departure time choice model based on individual passenger. The proposed model assumes that each passenger's behavior is heterogeneous based on stochastic process by relaxing the assumption of homogeneity among passengers and travelers have imperfect information and bounded rationality to more actually represent and to simulate each passenger's behavior. The proposed model integrated a inference and preference reforming procedure into the learning and decision making process in order to describe and to analyze the departure time choices of transit passengers. To analyze and evaluate the model an example transit line heading for work place was used. Numerical results indicated that in the model based on heterogeneous passengers the travelers' preference influenced more seriously on the departure time choice behavior, while in the model based on homogeneous passengers it does not. The results based on homogeneous passengers seemed to be unrealistic in the view of rational behavior. These results imply that the aggregated travel demand models such as the traditional network assignment models based on user equilibrium, assuming perfect information on the network, homogeneity and rationality, might be different from the real dynamic travel demand patterns occurred on actual network.

• Journal of Korean Society of Transportation
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• v.33 no.2
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• pp.125-135
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• 2015

In this study our main focus is to verify the relationship between social value of transportation system and its perceived features. To achieve this objective, we investigated the value of public bike system (PBS) through willingness to pay (WTP) analysis using contingent valuation method (CVM) and the survey was conducted for 1726 respondents who live in Suwon, Korea. Moreover the determinants related to features related to bicycle use were also gathered. The estimated binary logistic regression and censored regression reveal that the value of PBS is influenced by perceived features towards bicycle use incorporating non-congestion, transportation mode like auto and bus, and high mobility system as well as other variables such as income, bicycle ownership etc. Furthermore the results show that the perceiving of positive features to bicycle use leads to higher social value of PBS. Based on the findings, we discuss the importance of pre-review for transport policy implementation, and also explore the possibilities for application to PBS.