• Korean journal of communication and information
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• v.46
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• pp.590-626
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• 2009

The limitation and scarcity of broadcasting waves provide important rationale behind the idea of public ownership of broadcasting waves which can facilitate communications among people with diverse backgrounds and values in the society. Independence of broadcasting industry from the regulatory organization is imperative for the broadcasting industry to serve the public interest that has been historically defined by each county. For the Korean broadcasting industry, history of modern Korea taught us that the broadcasting regulatory organizations such as Korea Communications Commission(KCC) should be kept from any political influence for the industry to best serve the public. Recent controversies on the role of the CEO of KBS and the appointment of the CEO of YTN by the president of the country provide evidence that the independence of broadcasting in Korean society is a critical topic. This study examined the corporate structures of broadcasting industry and the political independence of the industry in relation to the changes in the concept of public interest and the role of broadcasting. It is critically important to investigate the political independence of broadcasting in Korea because the core argument of independence of broadcasting which is about the freedom of expression protected by the constitution is still contested in the country. For the purpose of collecting diverse perspectives on broadcasting, survey method was adopted in this study. Three groups Abstracts 697 of participants were recruited: reporters, experts in the field, and regular citizens. The result indicated that the independence of broadcasting was in the process of deterioration. Also, the participants of the study understood that it was impossible for the broadcasting to serve the public interest when the broadcasting was not free from the influence of regulatory institutions such as KCC.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.9 s.339
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• pp.85-96
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• 2005

A ' Virtual Private Network (YPN) over Internet' has the benefits of being cost-effective and flexible. However, given the increasing demands for high bandwidth Internet and for reliable services in a 'VPN over Intemet,' an IP/GMPLS over DWDM backbone network is regarded as a very favorable approach for the future 'Optical VPN (OVPN)' due to the benefits of transparency and high data rate. Nevertheless, OVPN still has survivability issues such that a temporary fault can lose a large amount of data in seconds, moreover unauthorized physical attack can also be made on purpose to eavesdrop the network through physical components. Also, logical attacks can manipulate or stop the operation of GMPLS control messages and menace the network survivability of OVPN. Thus, network survivability in OVPN (i.e. fault/attack tolerant recovery mechanism considering physical structure and optical components, and secured transmission of GMPLS control messages) is rising as a critical issue. In this Paper, we propose a new path establishment scheme under shared risk link group (SRLG) constraint for physical network survivability. And we also suggest a new logical survivability management mechanism by extending resource reservation protocol-traffic engineering extension (RSVP-TE+) and link management protocol (LMP). Finally, according to the results of our simulation, the proposed algorithms are revealed more effective in the view point of survivability.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.12
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• pp.8-14
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• 2011

The optimal geometry of the gate field plate in AlGaN/GaN-on-Si HEMT has been proposed using two-dimensional device simulation to achieve a high breakdown voltage for a given gate-to-drain distance. It was found that the breakdown voltage was drastically enhanced due to the reduced electric field at the gate corner when a gate field plate was employed. The electric field distribution at the gate corner and the field plate edge was investigated as functions of field plate length and insulator thickness. According to the simulation results, the electric field at the gate corner can be successfully reduced even with the field plate length of 1 ${\mu}m$. On the other hand, when the field plate length is too long, the distance between field plate and drain electrode is reduced below a critical level, which eventually lowers the breakdown voltage. The highest breakdown voltage was achieved with the field plate length of 1 ${\mu}m$. According to the simulation results varying the $SiN_x$ film thickness for the fixed field plate length of 1 ${\mu}m$, the optimum thickness range of the $SiN_x$ film was 200 - 300 nm where the electric field strength at the field plate edge counterbalances that of the gate corner.

• Journal of Adhesion and Interface
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• v.4 no.3
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• pp.33-40
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• 2003

In this work, diglycidyl ether of bisphenol A (DGEBA)/polyetherimide (PEI) blends were cured using 4,4-diaminodiphenyl methane (DDM). And the effects of addition of different PEI contents to neat DGEBA were investigated in the thermal properties and fracture toughness of the blends. The contents of contents of containing PEI were varied in 0, 2.5, 5, 7.5, and 10 phr. The cure activation energies ($E_a$) of the cured specimens were determined by Kissinger equation and the mechanical interfacial properties of the specimens were performed by critical stress intensity factor ($K_{IC}$). Also their surfaces were examined by using a scanning electron microscope (SEM) and the surface energetics of blends was determined by contact angles. As a result, $E_a$ and $K_{IC}$ showed maximum values in the 7.5 phr PEI. This result was interpreted in the increment of the network structure of DGEBA/PEI blends. Also, the surface energetics of the DGEBA/PEI blends showed a similar behavior with the results of $K_{IC}$. This was probably due to the improving of specific or polor component of the surface free energy of DGEBA/PEI blends, resulting in increasing the hydrogen bonding of the hydroxyl and imide groups of the blends.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.1
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• pp.93-102
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• 2006

In order to use a recycled aggregate concrete for precast concrete box structures, the structural behaviors should be analytically and experimentally evaluated. In this study, full-scale precast concrete box structures are manufactured using the recycled aggregate (30% replacement) and natural aggregate. Then, the flexural failure test and shear failure test as well as water leakage lest for the structures arc carried out. First of all, test results of compressive strength show that recycled aggregate concrete is only 4% lower than normal concrete. In the flexural and shear failure test, the structural performances of precast box using the recycled aggregate concrete are 95% of the capacities of normal precast concrete box or more. Especially, the water leakage test shows that leakage pressure of recycled concrete box is more than the critical value, 60kPa, as well as 9% higher than normal precast concrete box. These test results are analyzed and compared with results of finite clement analysis. The comparison shows that test results are more excellent than analytical results. Also, the comparison confirms the applicability of recycled aggregate concrete for the use as practical precast concrete box structure.

• Journal of the Korean GEO-environmental Society
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• v.16 no.5
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• pp.55-66
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• 2015

Big tidal differences, which range from 3.0 m to 8.0 m, exist with regional locations at south and west shores of Korea. Under this ocean circumstance, since a large scour may occur due to multi-directional tidal current and transverse stress of the wind, the scour surrounding the wind turbine structure can make instability of the system due to unexpected system vibration. The hydraulic resistance capacity of soils consolidated under different pressures are evaluated by Erosion Function Apparatus (EFA) under unidirectional and bi-directional flows in this study. It was found that the flow direction change affects significantly on the sour rate and critical shear stress, regardless of soil types while the consolidation pressure affects mainly cohesive soil. Among geotechnical parameters, the undrained shear strength can be well-correlated with the hydraulic resistance capacity, regardless soil type while the shear wave velocity shows the proportional relationships with the hydraulic resistance capacities of fine grained soil and coarse grained soil, respectively.

• Journal of The Korean Association For Science Education
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• v.18 no.4
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• pp.527-537
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• 1998

This article is a part of a research on the elementary science curriculum development to enhance creative problem-solving abilities. The components of the curriculum have been identified as 'scientific knowledge', 'process skills' & 'divergent/critical thinking'. Among these components, construction of the scientific knowledge that enables creative problem-solving abilities has been selected as an intensive research topic for the purpose of the present research. To avoid or to prevent the knowledge learned from separate facts and concepts, five themes have been selected so as to incorporate with all three areas of the elementary science curriculum, i.e., physical science, earth science and life science. The five themes are, 'structure', 'change', 'interaction', 'energy' and 'stability'. The contents of elementary science, which have been selected from the 3rd, 6th and 7th National Elementary Science curriculum, were reconstructed based on the five themes given above. The results of reconstruction are presented in the form of matrix, such that the vertical axis represents how the concepts are related within each domain of science, while the horizontal axis shows how the concepts are interconnected between domains of science. Therefore, based upon the five themes, individual or separate knowledge can be put into more unified knowledge so that contribution of knowledge transfer to new ones can be expected for leaners who will be creative in problem-solving. The process and products of the curriculum development as well as the background of the present research are described and discussed in detail.

• Journal of the Korean Geosynthetics Society
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• v.4 no.3
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• pp.35-43
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• 2005

The geosynthetic reinforced segmental retaining walls(SRW) are improved that the disadvantage of existed retaining wall and the workability in field. Recently, the segmental retaining wall is replacing the exited wall because it is quickly advanced to using by the block in-situ. The use, therefore, is increasing. But, the trends of the large scaled construction was developed that the problems likely to crack and collapse, those are caused of careless in design and construction of SRW not considering about various surrounding conditions. In this study, the cause analysis on destructed SRW was carried out that based on the datum of measured displacement of walls, rainfall features and ground sounding conditions. Also, the analysis of the global slope stability was carried out on collapsed section and non-collapsed section using critical equilibrium method. For the rational stability and analysis of slope including SRW structure, the site conditions including situations of topography, ground and histories of construction and collapse etc should be considered. The rational countermeasure methods for non-collapsed and collapsed areas may be sustained as much as possible current state.

• Journal of the Korean Geographical Society
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• v.51 no.5
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• pp.713-737
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• 2016

This study is to review research issues on North Korea and unified territory in terms of topics and approach method in Korean human geography. The conclusion of this paper is as follows. Before 1980's, topics on political geography, such as geopolitics or unified land, were the main stream in research. In 1990's with the end of the cold war and the access to material which was published in North Korea, scope of research was widened especially in geography education. After 2000's with the expansion of cooperation between South and North Korea, the scope of topics were more expanded in all field of human geography, for example, critical geopolitic in political geography, Gaeseong Industrial Complex, Najin-Seonbong region in economic geography, place names, Geumgangsan, North Korean defectors in social and cultural geography. The approach method of toward North Korea is fall into two categories. One is regional geography and the other is the unified land. In the latter approach, topics on the regional structure after reunification or on the life adaptation of defectors in South Korea etc. were studied. After unification of land, new Korean Studiea will be established and human geographers should make ready for this. Before unification, research on the land in north Korea should be proceeded in terms of historical geography.

• Korean Journal of Construction Engineering and Management
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• v.4 no.3 s.15
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• pp.128-136
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• 2003

The contractors which execute the design-build project have difficulties in design management and contract administration in the pre-construction phase because they have managed construction projects focused on only construction phase so far. Moreover, they have to manage the design development stage without any contingency following-up various design revisions from the design reviews of outside experts. Therefore, the design management in the design development stage is a critical success facto. of the design-build project. The objective of this study is to structure the problems in the management skill for design development phase in the domestic design-build projects and to suggest a design development management method to settle the problems. To achieve these objectives, this study 1) analyzes the prior studies about the design-build procurement methods, 2) designs and performs a case study to embody the problems of the domestic design-build projects, and 3) proposes a method of design development management by analyzing the results of case study and interviewing experts.