• The Journal of the Korea Contents Association
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• v.12 no.11
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• pp.368-376
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• 2012

Government has strictly regulated the concentration of the media market because the number of broadcasters was traditionally limited and they had significant influence on public. However as the media market converges with Internet's open architecture, scarcity and pervasiveness are losing their roles in justifying media regulation. This article examines market convergence and its impact on market concentration, and criticizes the current concentration regulation. The study indicates that market performance are much governed by firm's competitive actions than market structure, and that vertical integration contributes to service innovations, and that horizontal concentration makes it difficult to measure due to its even-changing market definition. Therefore, the regulation for market concentration should shift its focus from firm's market share to broadcaster's unfair acts driving market inefficiency and hurting content diversity.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.360-360
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• 2020

조립식 빗물침투형 저류블록은 우수유출 저감시설로, 황토 및 친환경 무기질 결합재를 이용하여 제작한 고강도 투수성 블록의 적층 및 요철에 의한 끼움식 조립에 의해 형성된 공간에 빗물을 저류하고, 저장된 빗물은 시간이 지남에 따라 지반으로 침투시키는 우수유출 저감용 빗물관리시설로, 집중강우 시 유출수가 발생하는 해당지역에 분산식으로 설치하여 국지적 호우 발생에 대처할 수 있으며, 지속적인 침투를 통한 지하수위 확보 및 가뭄현상의 저감은 물론, 미기후 조성과 건전한 물순환 구조 형성에 이바지하는 빗물관리기술이다. 본 기술은 집중형 대규모 빗물저류조의 적용상의 문제점과 단순저류의 한계성을 극복하고, 기존 침투시설의 낮은 침투능을 증대시키고자 저류기능과 침투기능을 동시에 확보하여 집중호우시 빠른 침투저류능을 향상시킨 조립식 빗물침투형 저류시설이다. 보다 구체적으로는 집중강우에 대한 방재적 측면과 함께 가뭄으로 발생하는 지하수위 저하 등에 친환경적으로 대응하기 위한 복합적인 빗물관리 기술로서, 빗물 유출저감과 함께 물순환 회복 및 저영향개발을 위한 각 지자체의 지침과도 부합될 수 있다. 또한, 콘크리트 제품의 환경적 문제점과 플라스틱 제품의 낮은 물성을 극복하였고, 시공 시에는 보다 현장상황에 맞게 가변적 형태로 적용이 가능한 단순조립 적층공법으로 공기단축에 탁월한 장점이 있으며, 유지관리 시에는 별도의 동력이 요구되지 않는 형태로 개발하였다. 조립식 빗물침투저류블록의 구조체를 이루는 단위 블록유닛은 투수성 소재로 제작되며, 상하부가 개방되어 있고 사각형의 내부에 힘을 받는 격벽과 전후벽이 상호 대응되는 요철로 형성되어 있으며, 단위블록 유닛 다수개가 수직수평으로 연속적으로 조립되어 규모의 제한, 형태의 제한이 없는 구조물 형성이 가능하다. 본 구조체의 저류공극율은 80%이상 확보 가능하며, 또한 블록자체의 투수율이 0.83mm/sec로서 순모래나 순자갈의 포화투수계수보다 투수율이 높아 침투저류 효율성이 높으며 시공 후 상부 토지는 자유롭게 활용 가능하다. 본 조립식 빗물 침투형 저류블록을 이용하여 저영향개발 계획, 우수유출 저감대책 수립, 빗물관리시설 계획시 기존의 시설들에 비하여 경제적, 효율적인 설계가 가능하다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.8B
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• pp.492-501
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• 2007

UMTS-WLAN interworking approach can make the best use of the advantages of both networks by eliminating the stand-alone defects of the two services. For the interworking mechanisms of WLANs and UMTS networks, two major solutions have been proposed, namely loose coupling and tight coupling. The loose coupling approach provides separate data paths for WLAN and UMTS. On the other hand, the tight coupling provides a full integration of the WLAN network and the UMTS core network. The loose coupling has been preferred due to the simplicity and less reconfiguration requirement. However, loose coupling is worse in seamless mobility, QoS provision, and network security. In order to lessen the problems involved in the UMTS-WLAN interworking approaches, we propose a new interworking network architecture and a fast vertical handover scheme by employing Mobility Anchor(MA) for interworking between the two different networks. MA can enable authentication and session initialization before L2 handover of the mobile terminal, so that the seamless and fast vertical handover become possible. Thru analysis and numerical experiments, we proved that the proposed scheme has been validated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.12
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• pp.1416-1426
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• 2008

In this paper, we present a small size and multiband directional dipole antenna for mobile communication repeaters. In the omni-directional dipole antenna, a planar reflector under the dipole provides improved directivity in front-direction with wide beamwidth. In order to miniaturize the directive dipole, the size of the reflector is reduced. A vertical stub on the reflector is proposed to enhance the front-directivity of the radiation pattern and mitigate the backward radiation due to the reduced reflector. Furthermore, we use horizontal stubs on edge of vertical stub to obtain additional reduction of the antenna size. To meet the current demand of wireless communication service, the designed antenna shows wideband characteristic by employing electromagnetic coupled two-dipoles with dual-resonance frequencies.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.4 s.95
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• pp.397-401
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• 2005

In this paper, a slot-coupled microstrip antenna with switchable polarization is proposed for the polarization diversity applications in the complicated communication environment. The proposed antenna is fed by a microstrip line through one of two slots located with the interval of $\lambda{g}/4$ in the ground plane. By switching the PIN diode between opened and shorted termination which is located at the tip of the microstrip line, the switching function between horizontal and vertical polarization was confirmed experimentally. The measured resonant frequencies of the fabricated antenna are $2.41\;\cal{GHz}\;2.40\;\cal{GHz}$ and the cross polarization levels are $19\;\cal{dB},\;23\;\cal{dB},\;the\;-10\;\cal{dB}$ return loss bandwidths are $95\;\cal{MHz}\;100\;\cal{MHz}$ in horizontal and vertical polarization, respectively, and the antenna gain is almost $6\;\cal{dBi}$.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.1
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• pp.30-42
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• 2010

The effects of internal waves on dynamics of hypoxic waters were investigated by numerical simulation by means of a hydrostatic-ecosystem coupled numerical model for Lake Biwa. The numerical model consists of hydrostatic and ecosystem submodels. Numerical simulation was carried out for a period during April 2007 and March 2008, after preliminary numerical simulation for three years. As a result, the numerical model could capture the vertical profiles of the observed water quality. During September 30 and October 21 in 2007, the major internal waves were Kelvin and Poincare waves, the periods of which were 1.63 or 1.77 days and 0.48 days, respectively. Hypoxic waters appeared in bottom boundary layer around October and were still when thermocline locates in upper layer. During late autumn and winter seasons, differences in density between upper and lower layers were reduced and the amplitude of internal waves increased. Hypoxic waters began to move under the effects of internal waves. Movement of hypoxic waters will diminish the habitat for aquatic organisms in deeper waters.

• Geophysics and Geophysical Exploration
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• v.14 no.2
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• pp.164-175
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• 2011

Using natural electromagnetic (EM) fields at low frequencies, magnetotelluric (MT) surveys can investigate conductivity structures of the deep subsurface and thus are used to explore geothermal energy resources and investigate proper sites for not only geological $CO_2$ sequestration but also enhanced geothermal system (EGS). Moreover, marine MT data can be used for better interpretation of marine controlled-source EM data. In the interpretation of MT data, MT modeling schemes are important. This study improves a three dimensional (3D) MT modeling algorithm which uses edge finite elements. The algorithm computes magnetic fields by solving an integral form of Faraday's law of induction based on a finite difference (FD) strategy. However, the FD strategy limits the algorithm in computing vertical magnetic fields for a topographic model. The improved algorithm solves the differential form of Faraday's law of induction by making derivatives of electric fields, which are represented as a sum of basis functions multiplied by corresponding weightings. In numerical tests, vertical magnetic fields for topographic models using the improved algorithm overcome the limitation of the old algorithm. This study recomputes induction vectors and tippers for a 3D hill and valley model which were used for computation of the responses using the old algorithm.

• Journal of IKEEE
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• v.11 no.4
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• pp.158-164
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• 2007

In this study, three types of a novel Trench IGBTs(Insulated Gate Bipolar Transistor) are proposed. The first structure has P-collector which is isolated by $SiO_2$ layer to enhance anode-injection-efficiency and enable the device to have a low on-state voltage drop(Von). And the second structure has convex P-base region between both gates. This structure may be effective to distributes electric-field crowded to gate edge. So this structure can have higher breakdown voltage(BV) than conventional trench-type IGBT(TIGBT). The process and device simulation results show improved on-state, breakdown and switching characteristics in each structure. The first one was presented lower on state voltage drop(2.1V) than that of conventional one(2.4V). Also, second structurehas higher breakdown voltage(1220V) and faster turn off time(9ns) than that of conventional structure. Finally, the last one of the proposed structure has combined the two structure (the first one and second one). This structure has superior electric characteristics than conventional structure about forward voltage drop and blocking capability, turnoff characteristics.

• Archives of design research
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• v.18 no.4 s.62
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• pp.65-72
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• 2005

The expected demands for the new styling design can be studied by examining the recent deliveries and the new buildings on order. These ships are setting the trend for the operation of passenger ships. There has been a rapid increase in size and produce of ship some remarkable exterior design image. These ships follow very similar design concept, even if their operator compete with each other in the same market. But also new innovative design solution have been introduced to catch the interest of the passengers. The propose of this study is to investigate the exterior styling design in passenger ships, which result form examining the exterior elements such as funnels, pods, hulls, trademark, colours, flowing curvilinear lines and from. Each different passenger ship lines require different design style for different markets, while ships of different sizes and categories obviously require different solution. When a new class is created later, key design element will be retained, with some items being changed and new ideas introduced.

• Journal of Advanced Navigation Technology
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• v.7 no.2
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• pp.101-107
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• 2003

In this study, we provide a single element log-periodic antenna that the feeding networks and array structures are aperture coupled and series dipole array type. We made the antenna for direct receiving the Moogoongwha satellite broadcasting signal. The transmission power was able to feed the patch dipole in series due to lay perpendicularly 8 series patch dipole on tapered slot. The patch dipole radiation pattern which fed in series power, make the main beam direction up $37^{\circ}{\sim}42^{\circ}$ within the BS/CS bandwidth. The main beam gain was measured 9.31~11.03 dBi. Using 32 elements to array the elements properly, we acquire $4{\times}8$ array structure on limited PCB board. As a result, it has been found that the new planar DBS antenna structure have high gain over 10dBi and acceptable elevation angle over 42 degree, and we can apply this result to commercial DBS reception antenna manufacturing.