• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.10
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• pp.1190-1196
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• 2016

In this paper, a cross-layer interworking scheme for different protocols is proposed to provide an efficient internet services in very small aperture terminal (VSAT) based satellite communication systems. In addition, we implement the proposed interworking model and prove the feasibility of the proposed system. VSAT based satellite communication systems commonly use digital video broadcasting (DVB)-S2 standard. Unfortunately, DVB-S2 has inefficient parts to support IP based internet services because it has originally been designed to support broadcasting services. Generic stream encapsulation (GSE) protocol, which is a layer 2 protocol, has been proposed to mitigate this inefficiency. We propose a cross-layer interworking scheme to cooperate efficiently between IP and GSE protocols and between GSE protocol and DVB-S2, respectively. In addtion, we implement the proposed interworking schemes via computer softwares and prove the feasibility using NI-USRP and commercial DVB receiver.

• Korean Journal of Materials Research
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• v.11 no.2
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• pp.137-145
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• 2001

A new process, gelcasting in aqueous medium, to fabricate complex-shaped ceramic core has investigated. The ceramic slurry, mixture of fused silica powder and additives such as zircon and cordierite, was electrosterically stabilizes. The slip was prepared by ball milling of polydispered ceramic suspension with monomer, dimer and dispersant. The rheological behavior of slip was evaluated by viscosity measurement. It was found that the high solid loading of polydispersed ceramic slip, which has low viscosity of 50vol%, is possible to obtained. The viscosity of the slip was significantly dependent upon the amount of polymer dispersant and the formulation of monomer and dimer. The green bodies were fabricated through casting and gelation at room temperature followed by drying at $25^{\circ}C$ for 48hrs under relative humidity of 80~85%. Crack-free green body was successfully fabricated through the above process.

• Korean Journal of Materials Research
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• v.12 no.7
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• pp.573-579
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• 2002

Stoichiometric mullite ($3Al_2$$O_3$. $2SiO_2$) precursor sol has been prepared by sol-gel method. The effects of the precursor pH and sintering temperature on the synthesizing behavior and morphology of mullite have been studied. Mullite precursor sol was prepared by dissolution of aluminum nitrate enneahydrate (Al($NO_3$)$_3$.9H$_2O) into the mixture of silica sol. Precursor pH of the sols was controlled to acidic condition ($PH\leq$ 1~1.5) and to basic condition ($pH\geq$8.5~9). The synthesized aluminosilicate sols were formed under 20 MPa pressure after drying at $150^{\circ}C$ for 24 hours, and then sintered for 3hours in the temperature range of $1100~1600^{\circ}C$. From TGA/DTA analysis, total weight loss in the aluminosilicate gel of the acidic sample was (equation omitted) 56% and that of the basic sample was (equation omitted) 85%, indicating that the synthesizing temperature of mullite phase for acidic and basic samples was above $1200^{\circ}C$ and $1300^{\circ}C$, respectively. The morphologies of the synthesized mullite were fine and needle-like (or rod-like) for acidic sample, and granular for basic sample that has been sintered above $1300^{\circ}C$. It was found that the morphology of mullite particle was predominantly governed by precursor pH and sintering temperature.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.26-26
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• 2019

본 연구는 2016년부터 2017년까지 한국 정부가 선정한 다수의 도시재생사업 중 수변공간 관련 사업을 선별하여 세부내용을 살펴보고 수변공간 도시재생사업의 거버넌스 특성을 분석한다. 도시재생사업에서 거버넌스는 사업의 성패를 가르는 핵심 요소로 대두되고 있다. 특히, 협업을 통한 민간 커뮤니티의 역할과 주민참여는 더욱 중요한 비중을 갖게 되었다. 본 연구는 Tallon(2013)의 도시재생 거버넌스 네 가지 형태-관주도(top-down), 주민주도(bottom-up), 시장주도(market-led), 지주주도(property-led) 재생을 기준으로 도시재생사업 활성화계획의 세부내용을 분석한다. 향후 도시재생사업의 추진 및 시행단계에서 거버넌스의 역할이 제대로 작동할 수 있도록 시사점을 제공하고자 한다. 연구의 공간적 범위를 수변공간을 한정하여 분석한 결과 총 20개의 도시재생사업이 도심 내 하천변과 해안가를 활용하여 추진되고 있었다. 구체적인 사업의 형태로는 (1) 생태하천복원, (2) 역사문화자원을 연계한 수변관광지 개발, (3) 수변네트워크 녹지 산책로 조성 (4) 항구 기반 수변도시개발 및 도심재생, (5) 섬의 이점을 활용한 수변경관사업, (6) 조선업 침체지역재생 등이 있었다. 한국의 수변공간 도시재생사업은 가장 일반적인 도시재생방식인 '관주도'로 진행되고 있었다. 그러나 지역의 권한과 역할을 강화하고자 하는 노력은 우선시되고 있었다. 또한, 관계부처 및 공공기관과의 파트너십 구축을 통한 도시재생사업의 효과성 향상을 도모하고 있었다. 특히, 부산시 영도구와 경상남도 통영시의 도시재생사업에서 협업의 노력이 두드러지게 나타났다. '마을만들기'와 같은 주민주도의 도시재생방식은 '주민참여협의체'를 통하여 일부 반영되고 있었다. 예를 들어, 서울시 도봉 노원구, 인천시 부평구, 경상남도 김해시, 부산시 영도구 등이 해당한다. 그러나 구체적인 실천 방안을 통한 주민주도 도시재생 거버넌스를 구축하는데는 부족함을 보였다. 더불어 민간투자를 유치하는 시장주도의 도시재생 접근은 찾아볼 수 없었다. 도시재생사업의 장기적이고 통합적인 특성을 고려했을 때, 안정적인 도시재생사업 추진을 위한 재원 마련에 대한 지속적인 노력이 요구된다.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.1
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• pp.95-102
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• 2018

Public spaces in the cities are social and economic resources to maintain sustainable urban revitalization. As an importance of public spaces is getting increased, many cities focus on public space management and introduce their own management system. NYC Plaza Program is one of the public space management systems in USA and it was designed in order to transform underused roads and streets into pedestrian public spaces throughout the New York City. Plaza management system works with private organizations' participation as NYC Department of Transportation empowers selected private organizations to the right of management and assists their efforts. In this study, we focused on how the plazas are managed by private sectors and seek to find out characteristics of types of management methods based on landuse(residential, commercial and openspace) status around plazas. We analyzed 61 plazas that generated by NYC Plaza Program with three major conditions of management system including organization, fund and activities. There are three major findings from the analysis. 1)In most residential surrounded plazas, resident-initiative organizations manage small scaled fund and activities meanwhile public agencies support their management. 2)BID is a dominant tool in the commercial surrounded plazas. BID provides with secured fund, mid-sized activities and a broad network with commercial facilities. 3)Openspace-surrounded types are usually using supports of exiting organizations and fund system.

• Korean Journal of Metals and Materials
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• v.50 no.4
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• pp.310-315
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• 2012

Nano-powders of 1.5TiAl and $Al_2O_3$ were synthesized from $1.5TiO_2$ and 3Al powders by high energy ball milling. Nanocrystalline $Al_2O_3$ reinforced composite was consolidated by pulsed current activated sintering within 2 minutes from mechanochemically synthesized powders of $Al_2O_3$ and 1.5TiAl. The relative density of the composite was 99.5%. The average hardness and fracture toughness values obtained were $1250kg/mm^2$ and $10MPa{\cdot}m^{1/2}$, respectively.

• Korean Journal of Heritage: History & Science
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• v.55 no.2
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• pp.114-129
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• 2022

Securing a safe place to keep its collections in Busan, the interim capital during the Korean War, the National Museum of Korea could fulfill its mission to protect the national treasures. Right before Seoul was recaptured by the Communist forces, the museum managed to evacuate its collections to Busan in December of 1950. Until the armistice in 1953, a Korean government warehouse in Busan had to function as a temporary museum building. Protecting the national treasures in this small building, the National Museum of Korea had to maintain its role as a national museum and contribute in revitalizing cultural functions of Busan, the interim capital. The efforts led to hope for reconstructing the museum.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.5
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• pp.31-40
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• 2014

The importance of green spaces in the city is growing each day. Local governments are taking charge of park development works that are having difficulty in developing and managing urban parks due to high land value as well as a shortage in finances. This is even though an urban park is defined as an urban planning facility and the law provides park area per person. Civil residents, meanwhile, are using not only urban parks provided by law but also other green areas such as rivers, reservoirs, and school playgrounds because they recognize urban green areas by the concept of use. In this study, accordingly, urban green areas were sorted into two types, urban parks, parks provided by law, and other green areas, and the difference in use pattern and use satisfaction by type was analyzed. As a result of analysis, there was no remarkable difference between the two types. According to such results, it was found that it is necessary to include other green areas, such as rivers, reservoirs, school green areas, and apartment green areas in addition to the current park green areas provided by law when park area per person is calculated, and such calculation of urban green areas reflecting local characteristics can reduce local governments' financial burden and improve the effectiveness of future urban park policies. It is judged that such results can become a plan against the cancellation of unexecuted urban facilities. The fact that accessibility factors, such as road satisfaction, access convenience, and convenient movement, are affecting satisfaction with the use of urban parks suggests that it is important to improve urban park accessibilities rather than to quantitatively expand park area in order to improve satisfaction with urban parks. Considering that people travel to urban green areas mostly by walking, it is necessary for access convenience to conduct follow-up studies such as barrier-free and securing walking stability through analysis of routes to urban green areas.

• Korean Chemical Engineering Research
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• v.44 no.5
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• pp.444-452
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• 2006

This paper reports experimental excess molar volumes $V^E_m$ using a digital vibrating-tube densimeter and excess molar enthalpies $H^E_m$ by means of an isothermal microcalorimeter with a flow mixing cell for the binary mixtures{1,2-dichloropropane + 2-(2-methoxyethoxy)ethanol} and {1,2-dichloropropane + 2-(2-ethoxyethoxy)ethanol} at 298.15 K under atmospheric pressure. All the $V^E_m$ and $H^E_m$ of the two binary mixtures showed S-shaped forms, being negative for poor and positive for rich 1,2-dichloropropane mole fractions. These show that the excess properties were shown to be negative deviation from ideality due to the strong self-association effect among 2-(2-alkoxyethoxy)ethanol molecules at an early stage of mixing, a relatively high energy then is needed to break hydrogen bonds of 2-(2-alkoxyethoxy)ethanol with an increase ofhalogenated hydrocarbon molecular at high mole fraction of 1,2-dichloropropane. The values of excess molar properties($V^E_m$ and $H^E_m$) were fitted by the Redlich-Kister equation using Nelder-Mead's simplex pattern search method. The Wilson, NRTL, and UNIQUAC models were used to correlate the $H^E_m$ values.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.1
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• pp.75-84
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• 2021

In this study, the correlation between cement quality(chemical composition, mineral composition, and compressive strength) and amount of waste alternative fuels used in the cement manufacturing process and was investigated. Cement manufacturing facility using coal, soft plastics(plastics that are easily scattered by wind power, such as vinyls), hard plastics(plastics that do not contain foreign substances, waste rubber, PP, etc.) and reclaimed oil was analised. Data was collected for 3 years from 2017 to 2019 and let the amount of fuels used as an independent variable and cement quality data as a dependent variable. As a result, depending on the type and quality of the alternative fuel has not a significant effect on the chemical composition(Cl and LSF) and mineral composition(f-CaO, C3S contents). Contrary to the concern that the compressive strength of cement would decrease, there was a significant positive correlation between amount of alternative fuel used and cement compressive strength.