• Resources Recycling
• /
• v.24 no.2
• /
• pp.36-45
• /
• 2015

In this study, various sizes of waste ground rubber tire (WGRT) were devulcanized by a single screw extruder equipped with a sonicator in front of the die, and waste PP and devulcanized waste ground rubber tire (DWGRT) composites were prepared by an intermeshing co-rotating twin screw extruder. The crosslink density and percent devulcanization of WGRT and DWGRT for 40, 80 and 140 meshes were calculated. The mechanical properties of the composites were compared with each other. The effect of SEBS-g-MA as a compatibilizer was investigated on mechanical properties of both waste PP/WGRT and waste PP/DWGRT composites. The crosslink density was decreased with decreasing the WGRT size. On the other hand, the percent devulcanization was increased by adding the smaller size of WGRT. Also, tensile strength, impact strength and elongation at break of the composite with DWGRT were higher than those with WGRT. Especially, mechanical properties of the composites were significantly increased by adding the smaller size of WGRT and DWGRT. Addition of SEBS-g-MA into both waste PP/(D)WGRT composites exhibited better impact strength and elongation at break than the composites themselves.

• Korean Journal of Social Welfare
• /
• v.58 no.4
• /
• pp.65-92
• /
• 2006

The purpose of this study is to establish fundamental knowledge on the experience for building resource system using the social networks within the community. This study used a social capital perspective and the grounded theory method based on Strauss and Corbin(1998) and Corbin(2004). Interviews were conducted with 14 Korean social workers (general managers and assistant managers) at community welfare centers who have developed resources by using the social networks or social relations for more than 3 years. In creating autonomy and sustainability of community, there are four types of social worker's efforts in building resource system within the community: 'restoring norms of reciprocity', 'developing citizen's capabilities', 'mobilizing resources through community organizations', and 'utilizing external resource-networks'. These results are contribute to developing theory on social welfare resources using community networks according to characteristics of a community.

• Journal of Energy Engineering
• /
• v.19 no.4
• /
• pp.251-257
• /
• 2010

Korea have a plan to enforce the Renewable Portfolio Standard(RPS) in 2012 for climate change action and effective use of energy but because of lack of renewable energy resources and limits of technology development, it will be hard to fullfill a target for RPS obligation in domestic power generation sector and woodchip biomass cofiring with coal combustion is the one of the alternative methods of the goal. Woodchip biomass cofiring with coal combustion is easy to approach technical design and has competitiveness of $CO_2$ & renewble energy certificate benefit and also has much lower generation cost than any other renewable energy resources. Because of that reason, woodchip biomass cofiring with coal combustion should be needed to fullfill the goal for RPS obligation in domestic power generation sector with midlong-term direction.

• Journal of Korea Society of Industrial Information Systems
• /
• v.13 no.5
• /
• pp.117-123
• /
• 2008

In this paper, we develop MPEG-4 AAC streaming player on embedded Linux processor such as mobile terminals. Moreover we show the experimental results that the player preforms the decoding processes of MPEG-4 AAC data effectively. MPEG-4 AAC technology supports a wide range encoding rates and high sound quality so it is appropriate to adopt various applications. In particular, the need in the development of the application of audio data increases according to significantly increase in devices used in mobile environments, such as cell phones and PDAs. In this environment, it is necessary to optimize the decoding processes to the ability of the terminal hardware in order to play audio data without delays. We also implement the decoding module to optimize the processor capabilities and make the player to decode and play streaming audio data from streaming server.

• Journal of Digital Convergence
• /
• v.14 no.8
• /
• pp.195-201
• /
• 2016

The purpose of this study is to find out key factors of successful urban regeneration based on previous studies and relationships between those factors and revisit intention. To draw a conclusion, this study makes surveys including the variables of success factor(External environment factors, Internal environment factors, Internal cultural factors), degree of satisfaction, and degree of revisit intention. And it collects the data from respondents who had been to Gamcheon culture village in Busan. The data is analyzed by applying an exploratory factor analysis and a confirmatory factor analysis. The result of these analysis describes that the Internal environment factors and Internal cultural factors affect the satisfaction degree positively and the degree of satisfaction has positive effects on the revisit intention. The study finds out that unique resource properties should be considered when underdeveloped cities are regenerated. Future study is to generalize the theory through the sampling covered the whole country.

• Journal of Climate Change Research
• /
• v.3 no.2
• /
• pp.143-151
• /
• 2012

This study analyzes United Nations Framework Convention on Climate Change and domestic-foreign support policy for renewable, also confirms the need for sound and sustainable development to minimize adverse impacts on the environment. Main source of greenhouse gas emissions leading to global warming needs to be resolved through the introduction of renewable energy system by developing low-carbon city. Case studies show the directions for practical response to climate change on the basis of introduction of renewable energy. This case studies can be served as the base model that reduces greenhouse gases with the introduction of renewable energy facilities in the new land development project and obtains economic benefits from CDM project.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.18 no.1
• /
• pp.39-44
• /
• 2023

Renewable energy such as solar and wind power is a resource that is sensitive to weather conditions and environmental changes. Since the amount of power generated by a facility can vary depending on the installation location and structure, it is important to accurately predict the amount of power generation. Using meteorological data, a data preprocessing process based on principal component analysis was conducted to monitor the relationship between features that affect energy production prediction. In addition, in this study, the prediction was tested by reconstructing the dataset according to the sensitivity and applying it to the machine learning model. Using the proposed model, the performance of energy production prediction using random forest regression was confirmed by predicting energy production according to the meteorological environment for new and renewable energy, and comparing it with the actual production value at that time.

• Journal of the Economic Geographical Society of Korea
• /
• v.26 no.4
• /
• pp.443-457
• /
• 2023

This study aims to provide methods and policy implications for vitalizing the regional regeneration of local small cities through utilizing idle spaces, with Hongcheon-gun as a case. Hongcheon-gun has been changed into cultural and art space since it was selected as the venue of Gangwon Triennales, and it is an example region that vitalized local areas by utilizing idle spaces on the basis of its placeness and characteristics. For the effective future utilization of idle spaces and regional regeneration, however, first, the survey of local resources is required for the systematic management and utilization of idle spaces. Second, foundations for the management and operation of idle spaces should be constructed. Third, methods for utilization should be sought in consideration of the characteristics of idle spaces and local conditions. Fourth, connected projects should be vitalized in consideration of possibilities for the regeneration and utilization of idle spaces.

• Journal of KIISE:Information Networking
• /
• v.34 no.5
• /
• pp.379-388
• /
• 2007

With proliferation of computer and wireless network technology, it is common to access Internet through wireless network using mobile device. Ratio of using streaming media out of many applications through Internet is increasing not only in wired network but also in wireless network. Streaming media is much bigger than other contents and requires more network bandwidth and more computing resources. However mobile devices hate relatively poor computing resource and low network bandwidth. If media streaming service is provided for mobile devices without any consideration about network bandwidth and computing power, it is hard for the client to get high qualify service. Since mobile device is supported with very limited energy from the battery, media streaming should be adjusted to varying energy state of mobile device in realtime to ensure complete playback of streaming media. In this paper, we propose DFRC to provide high qualify service to mobile client through wireless network by controlling the number of frames transmitted to client based on computing resource and energy state of mobile device.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.185.1-185.1
• /
• 2010

원격탐사(remote sensing)란 관측 대상과의 접촉 없이 멀리서 정보를 얻어내는 기술을 말한다. 기상관측분야에는 이미 소다(SODAR) 장비가 폭넓게 사용되거 왔으나 최근 풍력자원평가(wind resource assessment)를 위한 풍황측정에 SODAR와 더불어 라이다(LIDAR)가 적극적으로 활용되기 시작하고 있다. 참고로 SODAR(SOnic Detection And Ranging)는 수직 및 동서 남북 방향으로 음파를 발생시키고 대기유동에 의해 산란 반사된 에코를 수신하여 진동수 변화와 반사에코 강도를 측정하여 각 방향의 에코자료를 벡터 합성함으로써 풍향 및 풍속을 산출하는 원리이다. 반면 LIDAR(Light Detection And Ranging)는 비교적 최근에 풍황측정 용도로 개발된 레이저 탐지에 바탕을 둔 원거리 센서로, 공기입자(먼지, 수증기, 구름, 안개, 오염물질 등)에 의해 산란된 레이저 발산의 도플러 쉬프트(Doppler shift)를 이용하여 풍향 및 풍속을 측정하는 원격탐사 장비이다. 풍력자원평가 측면에서 라이다는 그 정확도가 IEC61400-12에 의거한 풍황탑(met-mast) 측정자료 다수와의 비교검증 실측평가(Albers et al., 2009)를 통하여 입증된 바 있다. 한편 한국에너지기술연구원에서 운용 중인 라이다 시스템은 그림 1의 우측 그림과 같이 1초에 $360^{\circ}$를 스캔하여 50지점에서 반사되는 레이저를 스펙트럼으로 측정하되 설정된 관측높이에서 풍속은 샘플링 부피(sampling volume)의 평균값으로 정의된다. 그런데 샘플링 부피는 설정된 관측높이로부터 상하 12.5m, 총 25m의 높이구간에서 관측한 스펙트럼의 평균값을 그 중앙지점에서의 풍속으로 환산하는 알고리듬(algorithm)을 채택하고 있다. 따라서 비선형적으로 변화하는 풍속연직분포 관측 시 풍속환산 알고리듬에 의한 측정오차가 개입될 가능성이 존재하는 것이다. 이에 본 연구에서는 라이다에 의한 풍속연직분포 측정 시 샘플링 부피의 구간 평균화 과정에서 발생하는 불확도(uncertainty)를 정량적으로 분석함으로써 라이다에 의한 풍속연직분포 관측의 불확도를 정량평가하고자 한다.