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Abstract Limiting the increase of global temperature requires electrification of the railway transport, which is relatively a distinct mode of transport in terms of economy, business and socialization of a country. However, battery complemented railway transport systems such as fuel cell hybrid railway propulsion systems are constrained by the high cost of the battery, and suboptimal performance of the fuel cell under varying loads. Optimized selection of battery can reduce its costs associated with sizing, life and utilization. Similarly, managing the load distribution between the battery and fuel cell can reduce the load variations concern for fuel cell. In this study, model-based selective characterization of the battery and fuel cell is done to identify the optimal features and constraints. Following characterization, the load allocation to battery and fuel cell is determined with the targets of collaborative utilization of optimal features and mitigation of constraints. Subsequently, considering this load allocation and results of characterization, conditions are proposed for reliable sizing and optimized selection of battery. The significance of the proposed conditions in reliable sizing is explored. Based on these conditions, certain commercially developed batteries are evaluated for optimized selection of battery. The results signify this study as a foundation for research on the reliable sizing and optimized selection of battery in fuel cell hybrid railway propulsion systems.

As smart cities become a global topic, interest in smart mobility, the core of smart cities, is also growing. The technology that comes closest to general users is “autonomous driving”. In particular, the successful market entry and establishment of some private companies proved that “autonomous driving” is not technology of the future but imminent reality. However, safety in autonomous vehicles that rely on sensors instead of the driver’s five senses has been the focus of attention from the beginning and continues to be so. In this study, we attempted to counter this interest. Based on the actual data of thirty traffic accidents, assuming the AEBS (Autonomous Emergency Braking System) was installed to assist the driver in safe driving, it was reinterpreted through simulation to see what changes occurred in the accident. In the computer program, PC-Crash, the results were first analyzed through simulation using Euro NCAP (New Car Assessment Program)’s AEBS test standards. Subsequently, the other variables in the AEBS were controlled and the accident was reinterpreted by changing only the angle of the radar detection sensor. As a result, it was confirmed that a total of 27 accidents out of thirty accidents could have been prevented with the AEBS. In addition, it proved that the crash avoidance rate of vehicles gradually increased as the radar angle increased.

AbstractThe penetration of financialization into the biocultural geographies of islands builds upon processes of commodification and privatization of environments, entailing enclosures of resource commons, environmental destruction and displacement of people, their livelihoods, knowledge and practices, with implications for sustainability. Against this background I critique the growing literature on acronym models of island development, arguing for more careful consideration of issues concerning democracy, human rights and sustainability. Drawing on the ‘right to the city’ literature, I highlight the importance of the ‘right to the island’ in an effort to move beyond the policy imperatives of MIRAB, SITE and PROFIT. Exercising the right to the island involves cultivating radically pluralistic democracy through struggles for alternative island futures. In so doing it problematizes what it means to develop and achieve sustainability.

Abstract A change in the thermal environment of an urban area affects health, living conditions, and energy consumption. In urban planning, urban parks are one of the methods for improving the thermal environment and saving cooling energy. Urban park construction can mitigate temperature, but it also causes urban development by increasing local attractiveness. To achieve efficient energy saving through parks in urban planning, the purpose of this study is to investigate the relationship between building energy consumption and urban characteristics both before and after the construction of an urban park. This study targeted Seoul's Gyeongui line forest, which was recently converted into a linear park on the former railway as an urban regeneration project. We analyzed the relationship between energy consumption and urban characteristics using a regression model, focusing on the changes before and after the construction. In this study, urban characteristics include environment, building physical characteristics, and economic variables. The results show that the construction of the urban park reduced not only temperature but also building energy consumption. The energy reduction effect of the park was limited to a marginal distance. Meanwhile, the urban park construction caused land prices to rise and prompted new development, and this changed the urban characteristics of the area and affected energy consumption. Despite changes in urban characteristics, urban park planning is an effective methods of reducing the energy consumption involved in cooling urban areas. We recommend comprehensive consideration of the urban factors when making park policy to reduce urban temperature and energy consumption.

A smart gird is an emerging digital convergence technology contributing to economic and social development. With the introduction of smart grid, consumers increasingly play a critical role in the diffusion of the smart grid, and this highlights a need for examining the diffusion of the smart grid from the perspective of users. This study examines the factors influencing the adoption and diffusion of the smart grid from the perspective of users and provides some strategic guidelines for government and providers. In-depth interviews were conducted with 41 users of the smart grid in the Jeju testbed South Korea, the world’s largest community with smart grid. Data were analyzed by applying grounded theory. Nineteen categories representing factors influencing the diffusion of the smart grid were identified through open coding. Propositions integrating these factors consisted of incentives and promotions, providers’ passion and proactive attitudes, environmental and technological characteristics, continuous training and communication, and experience of economic benefits, among others. Guidelines for the successful diffusion of the smart grid in the initial stages of their introduction include conflict management, choice of appropriate technology, and authentic relationships with residents.

This study integrated a focus on geographical, physical, and commercial characteristics to explore the commercial gentrification phenomenon and its related statistical summaries in the area of Garosu-gil in Seoul’s Sinsa-dong ward. In particular, this study first collected parcel and building data and corresponding attribute information and mapped the resulting datasets in a geographic information system (GIS) environment. We then examined gentrification issues per building and conducted statistical analyses to investigate spatial patterns of commercial gentrification, which were used to develop criteria for determining degrees of gentrification. Third, this study conducted correlation and regression analyses to quantify the strength of the linear relationship between pairs of variables associated with primary factors contributing to commercial gentrification, and used a geographically weighted regression model (GWR) to help understand and predict spatial relationships between significant variables. The results showed positive correlations between several variables and commercial gentrification in the study area, namely neighborhood-convenience facilities, building ages, store rents, new franchise and restaurant businesses, distance to subways, and the presence of multiple roads. Based on its finding, there are key contributions of this study as follows. The first significant contribution of this study is developing measurement of gentrification levels that can be used by policy makers at each of four stages of the gentrification process. Furthermore, this paper develops a comprehensive approach for spatially identifying gentrifying neighborhoods across multiple time periods in 2- and 3-dimensions. It eventually helps urban planners implement preventative or supportive programs to protect lower-income residents and small businesses and thereby engender more sustainable community development.

The deposition of ash - combustion residues - on superheaters and heat exchanger surfaces reduce their efficiency; this phenomenon was investigated for a large-scale waste-to-energy incineration facility. Over a period of six months, ash samples were collected from the plant, which included the bottom ash and deposits from the superheater, as well as flyash from the convective heat exchanger, the economiser and fabric filters. These were analysed for particle size, unburned carbon, elemental composition and surface morphology. Element partitioning was evident in the different combustion residues, as volatile metals, such as cadmium, antimony and arsenic, were found to be depleted in the bottom ash by the high combustion temperatures (1000+°C) and concentrated/enriched in the fabric filter ash (transferred by evaporation). Non-volatile elements by contrast were distributed equally in all locations (transported by particle entrainment). The heat exchanger deposits and fabric filter ash had elevated levels of alkali metals. 82% of flyash particles from the fabric filter were in the submicron range.

Abstract Hydrogen is an important clean energy carrier that can facilitate and promote clean energy production and mitigate greenhouse gas emissions. However, long-term storage and long-distance transportation of hydrogen are challenging owing to its low energy density, which can be effectively enhanced via liquefaction, an energy- and cost-intensive process. Commercial hydrogen liquefaction processes exhibit specific energy consumptions in the range of 12.0–15.5 kWh/kg with an exergy efficiency of 19.0%–23.6%. This study presents an energy-efficient and cost-effective process configuration for producing liquid hydrogen through stepwise cooling and subsequent ortho–para conversion. The energy intensive precooling cycle is divided into two sub-cycles employing carbon dioxide as a refrigerant. This process exploits the benefits of carbon dioxide in a simple yet efficient configuration. A specific energy consumption of 7.63 kWh/kg was achieved, along with an exergy efficiency of 31.4%. The coefficient of performance and figure of merit of this study was 0.16 and 0.31, respectively. Economic evaluation yielded total equipment and total annualized costs of $12.3 million and $24.2 million/year, respectively. The proposed process can assist in achieving a sustainable and green energy economy by enhancing the overall hydrogen value chain through competitive and efficient hydrogen storage and transportation.