This paper describes the design and implementation of a electromagnetic energy harvesting mechanism and electronic circuit for autonomous emergency call system. This analysis results show the power output of the proposed harvesting mechanism and circuit up to max power output 5V and it can hold up to 65 msec of the power generation and 10msec of the RF transmission. Based on the these testing results, the implementation of autonomous emergency call device without battery power or any external power source is feasible.
According to industrialization and urbanization the number of increasing cars is attributable to an explosive increase of the vehicle emissions. In this study, in consideration of the population and local transportation characteristics of South Chungcheong Province the environmental and economic cost-benefit analyses are performed to evaluate whether the CNG bus conversion gives what kind of effects. Based on the analysis result the expansion and distribution plan of CNG bus is proposed for South Chungcheong Province, and the local supply policy model is also proposed considering the acquisition and management of the economic situation of CNG charging infrastructure and the small transportation companies.
For an effective energy management in intelligent buildings it is necessary to gather information about position/absence of people and the level of population. In this paper the smart occupancy detection system using the active RFID is developed to satisfy such a demand based on the results of previous research. First of all the design considerations and functions of the system are introduced. In sequence the functions of the system is presented, and then the performance of the developed system is tested and verified through various field tests. The developed core technology can be also applied to other fields such as security, healthcare, smart home, etc.
In the previous study, the construction guide line of IT infra-structure for a u-City was introduced. However, it is only concentrated on the components and construction procedure for provider-oriented and technology-oriented sensor networks. In this paper the architecture and building process of demander-oriented sensor networks for sustainable u-City service are proposed. In the paper it is described (1) the enhancement methods of the procedure that can be flexibly constructed according to the scale of the project, (2) the methods that can improve the structure from the wireless sensor network such as RFID/USN to the hybrid sensor network, and (3) the consideration factors for providing the sustainable u-City service.
For an effective energy management in intelligent buildings it is necessary to gather information about position/absence of people and the level of population. In this paper the smart occupancy detection system based on the active RFID is developed to satisfy such a demand. The performance of the developed system is tested and verified through various experiments. Furthermore the feasibility test of the active RFID tag is performed to verify whether it can be used as a location-based occupancy sensor. The developed core technology can be also applied to other fields such as security, healthcare, smart home, etc.
In the previous study, the construction guideline of IT infra-structure for a u-City was introduced. However, it is only concentrated on the components and construction procedure for provider-oriented and technology-oriented sensor networks. In this paper, it is described (1) introduction of the construction guideline of IT infra-structure for a u-City, (2) the problems of the previous study, and (3) the enhancement direction of the construction guideline of IT infra-structure for a u-City.
In this paper, the uAPSS(u-APartment Service System) that is based on location-aware technology is designed and implemented for a luxury apartment. On the real luxury apartment the developed system has been employed and tested to provide convenient and secure living for residents. It provides services such as emergency call, intelligent elevator operation, and hands-free door access based on the location of the residents with personal device as called smart tag. It can also be applied to other service areas such as the location-aware u-Service for hospitals, high-rising complex buildings, silver towns, etc.
현재까지 USN(Ubiquitous Sensor Network)이라 통칭되어지는 센서망은 불특정 공간에 배포된 무선방식의 센서노드를 통해 유선방식의 센서 인프라를 대체하려는 기술 지향적 및 공급자중심의 구성을 가지고 있다. 본 논문은 기존의 공급자 위주의 기술지향적인 제한적 구성에서 벗어나, u-City에서 제공하고자 하는 서비스들의 목적과 서비스 대상의 요구사항분석을 기반으로 성능, 품질, 비용 등을 고려하도록 다양한 기술들을 융 복합하여 서비스를 제공하는 하이브리드 센서망의 제안을 위한 선행 연구 결과이다. 우선, 센서망과 u-City 서비스와의 관계에 대해 서술한 후, 기존 센서망에 대한 조사, 분석 결과 및 문제점, 그리고 선진국에서의 하이브리드 센서망 적용 사례와 시사점에 대해 논의하도록 한다.
In this paper, the u-Service system that is based on location-aware technology is designed for a silver town. It provides services such as emergency call, intelligent elevator operation, and hands-free door access based on the location of the residents with personal device as called smart tag. It can also be applied to other service areas such as the location-aware u-Service for Hospital, high-rising complex building, APT, etc.
This study was performed to test the feasibility of thermophilic (55oC) co-digestion of municipal sewage sludge and food wastes. The management variables of co-digestion were the mixed ratios of municipal sewage sludge and food waste hydraulic retention times (HRTs). During the operation of thermophilic co-digestion, the reactor pH ranged from 7.0 to 7.5 and the reactor alkalinity remained above 3,200 to 4,000 mg/L as CaCO3. The volatile fatty acids concentration increased as the HRT shortened from 20 days to 10 days and the mixture ratio increased to 1:4, but did not reach toxic levels for co-digestion of sewage sludge and food wastes. Methane productivity increased gradually as the organic loading rate increased. Maximum methane productivity reached 1.03v/v-d at an HRT of 10 days and at the mixture ratio of 1:4. The TVS removal efficiency decreased from 70.6% to 58.3% as the HRT shortened from 20 days to 10 days. TVS removal efficiency ranged from 57.0% to 77% during the entire operation. It is likely that thermophilic co-digestion of sewage sludge and food wastes is a very effective method both to environmentally treat food waste and to economically produce gas for energy.
To produce palm kernel shell (PKS) biocrude oil, a bubbling fluidized bed pyrolyzer was used with different sample sizes and reaction temperatures. The PKS sample sizes used were 0.1 ~ 0.4 mm, 0.4 ~ 1.0 mm, and 1.0 ~ 2.0 mm and the reaction temperature were 465oC, 490oC, 530oC, 560oC, and 590oC. The yield of PKS biocrude oil increased with decreasing the sample size. The maximum yield of PKS biocrude oil was 47.31% at 560oC with a PKS sample size of 0.1 ~ 0.4 mm. In addition, the maximum energy yield of PKS biocrude oil was 45.05% at 560oC and size 0.1 ~ 0.4 mm. Among the characteristics of PKS biocrude oil, the high heating values are from 15.98 MJ/Kg to 20.29 MJ/Kg, the moisture content is from 20.14wt.% to 31.57wt.%, and the viscosity ranges from 0.0117 N s/m2 to 0.0408 N s/m2. In addition, proximate analyses and elemental analysis of PKS biocrude oil were conducted.
Converting biomass to biocrude oil has been extensively studied worldwide as a renewable energy technology and a solution to global warming caused by overuse of fossil fuels because it is a carbon neutral fuel that originates from biomass and, thus, could help prevent climate change. Fast pyrolysis is an effective technology for producing biocrude-oil, and woody biomass is usually used as feedstock. Although many studies have been performed with this feedstock, high production cost and low higher heating value (HHV) have frequently reported as challenging barriers to commercialization. Thus, coffee ground residue was selected as an alternative feedstock to overcome this barrier due to its higher HHV than other biomasses, as well as an expected improvement in the recycling rate of organic waste from many coffee shops. A kinetic study on the thermal decomposition reaction of ground coffee residue was carried out previously to investigate pyrolysis characteristics by thermogravimetric analysis, and its kinetic parameters were studied using two calculation models. A bubbling-fluidized-bed reactor was used for fast pyrolysis and the yield and characteristics of the biocrudeoil from ground coffee residue were investigated at reaction temperatures of 400-600°C. The activation energy of the decomposition reaction was calculated separately to be 41.57 kJ/mol and 44.01-350.20 kJ/mol with the above two methods. The highest biocrude-oil content was about 51.7wt% at 550°C.
The waste treatment cost and energy production benefit of Wonju city RDF plant, the first RDF manufacturing plant in Korea, were investigated in this study. All plant operation data, like total weight of received wastes, produced RDF and separated rejects in processes have been fully recorded for mass balance calculation of the plant. Also all consumed oil and electricity have been recorded for energy balance calculation. The results showed that the waste treatment cost not included the RDF sales price of 25,000 won/ton-RDF was 139,316 won/ton-MSW and it went down to 128,640 won when included the RDF price in 2011. Produced RDF was 42.7% of total received waste in weight. Three components analysis by mass balance calculation of total received waste showed that Wonju city's MSW was 34.0% of combustible, 35.0% of water and 31% of incombustible respectively. Energy effect was found that total amount of produced energy was about 4 times more than that of consumed energy. Analysis data for 5 years since 2007 were summarized and shown in this study.