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431.
Anna Lavoie Kim Sparks Stephen Kasperski Amber Himes-Cornell Kristin Hoelting Conor Maguire 《Coastal management》2013,41(5):359-387
AbstractCommunity vulnerability is increasingly evaluated through quantitative social indices, typically developed using secondary data sources rather than primary data collection. It is necessary to understand the validity of these indices if they will be used to inform policy and decision making. This paper presents a ground-truthing effort to validate quantitative indices that characterize the well-being of Alaska fishing communities. We utilized ethnographic data collected from 13 representative communities and a capital assets framework to ground-truth the indices, in which qualitative ranks of vulnerability were compared against quantitative indices. The majority (73.8%) of ranks were in complete or moderate agreement and the results indicate that most of the indices are representative of community vulnerability; yet some variables utilized to create the indices could be modified to better reflect realities in Alaska. Indices of commercial fishery engagement and reliance appeared to be more reliable than socio-economic indicators, particularly for smaller fishing communities. We also confirmed that the indices do not capture political, or ecological factors that affect levels of community vulnerability. We conclude that quantitative indices of community vulnerability are useful rapid assessment tools; however, they should be validated, and complemented with ethnographic data prior to their implementation as policy making and management tools. 相似文献
432.
Jongryeol Jeong Namwook Kim Wonsik Lim Yeong-Il Park Suk Won Cha Myeong Eon Jang 《International Journal of Automotive Technology》2017,18(5):891-900
In a hybrid electric vehicle (HEV) system, it is an important issue on how to distribute the output power from multiple power generating components to operate a vehicle more efficiently. Many studies have been conducted on how to manage multiple power sources of a vehicle based on various optimization theories. In this study, an algorithm to calculate the optimization of a series HEV that has three power generating components, engine, battery and ultra-capacitor, is developed based on dynamic programming. Normally dynamic programming is applied to the optimization of power management and components sizing by estimating potential fuel economy for electrified vehicle such as HEV, Plug-in HEV or Fuelcell HEV. In contrast with most objective systems that have only two power generating components, the system in this study has three power sources. Since the system has three power sources, the number of state and control variables of optimization problem increases. Therefore the number of calculations increases unreasonably. To decrease the number and time of calculations, a new electric model that contains the both characteristics of battery and ultra-capacitor is developed with some assumptions. In comparison with the optimization algorithm which follows the theory of DP with no assumptions, the results from the newly developed algorithm has 1.04 % discrepancy in terms of fuel economy, even though the calculation time decreases to 4400 times less. 相似文献
433.
Jeongwoo Lee Sanghyun Chu Jaegu Kang Kyoungdoug Min Hyunsung Jung Hyounghyoun Kim Yohan Chi 《International Journal of Automotive Technology》2017,18(6):943-950
Environmental problems have become a major issue for diesel engine development. Although emission aftertreatment systems such as DPFs (diesel particulate filters), LNTs (lean NOx traps) and SCR (selective catalytic reduction) have been used in diesel vehicles, the manufacturing cost increase caused by this equipment can be hard to be control. Thus, it is better for engine emissions to be reduced by improving the combustion system. A dual-fuel combustion concept is a recommended method to improve a combustion system and effectively reduce emissions. Low reactivity fuel including gasoline and natural gas, which was supplied to the intake port by the FPI (port fuel injector), improved the premixed air-fuel mixture conditions before ignition. Additionally, a small amount of high reactivity fuel, in this case diesel, was injected into the cylinder directly as an ignition source. This dual-fuel combustion promises lower levels of NOx (nitrogen oxide) and PM (particulate matter) emissions due to the elimination of local rich regions in the cylinder. However, it is challenging to control the dual-fuel combustion because the combustion stability and efficiency deteriorate due to the lack of ignition source and reactivity. Thus, it is important to establish an appropriate dual-fuel operating strategy to achieve stable, high efficiency and low emission operation. As a result of this research, a detailed operating method of dual-fuel PCI (premixed compression ignition) was introduced in detail at a low speed and low load condition by using a single cylinder diesel engine. Engine operating parameters including the gasoline ratio, a diesel injection strategy consisting of multiple injectors and timing, the EGR (exhaust gas recirculation) rate and the intake pressure were controlled to satisfy the low ISNOx (indicated specific NOx) and PM emissions levels (0.21 g/kWh and 0.1 FSN, 0.040 g/kWh, respectively) as per the EURO-6 regulation without any after-treatment systems. The results emphasized that a well-constructed dual-fuel PCI operating strategy showed low NOx and PM emissions and high GIE (gross indicated fuel conversion efficiency) with excellent combustion stability. 相似文献
434.
Myeong Jun Kim Tae Won Park In Kyeong Hwang In Chul Sung Hyoung Seok Kim Sang Do Na Sung Pil Jung Tae Hee Lee Kyung Up Mah Jae Yun Lee 《International Journal of Automotive Technology》2017,18(6):973-981
Worldwide, the tire market requires safe and eco-friendly tires. In this study, a self-inflating tire (SIT) was studied and manufactured. Self-inflating tire refers to a technique for maintaining appropriate tire pressure. An internal regulator senses when tire inflation pressure has dropped below the set air pressure. The tire boosts air through the valve when rolling and compressed air enters into the tire. This procedure keeps the tire air pressure at an appropriate level and increases tire safety. In this study, a regulator was used as a negative-pressure system. A check valve was selected the minute flow check valve depending on the shape of the configured system. In addition, the material of the tube was developed with excellent physical properties and resistances (elastic rebound, working temperature, etc.) owing to its complete compression and restoration. A tube performance tester was developed and a computer aided engineering (CAE) model was modeled for comparison with the test results. Using the tester and model, it was possible to optimize the shape of the tube and regulator. Finally, the reliability of the study was verified through the prototype test. The developed equipment and systems can be used for the manufacture of high-performance and safe tires. 相似文献
435.
J.-H. Yoo J.-S. Jang J. K. Kwon H.-C. Kim D.-W. Song S.-Y. Jung 《International Journal of Automotive Technology》2016,17(2):347-352
With the emergence of LED lighting, IT convergence technology using the visible spectrum of LEDs, such as Visible Light Communication (VLC), has been highlighted. Among the many VLC applications, vehicular VLCs based on LED headlamps and transportation lighting infrastructure, such as street lamps, traffic lights, etc., are considered good alternatives for Intelligent Transportation Systems (ITS) or Active Safety applications. This paper introduces a demonstration system of vehicle-to-vehicle (V2V) VLC based on LED headlamps. By applying an inverse 4-PPM modulation scheme satisfying a 75 % dimming level under the light distribution regulation of LED headlamp, the proposed system showed its capability for V2V VLC with a 10 kbps data rate for more than 30 m under day time conditions. By measuring the BER performance according to distance, outdoor V2V VLC was possible for more than 30 m even in the day time. 相似文献
436.
N. T. Jeong S. M. Yang K. S. Kim M. S. Wang H. S. Kim M. W. Suh 《International Journal of Automotive Technology》2016,17(1):145-151
Nowadays, a number of environmental issues have seriously come to the fore. For this reason, the R & D spending on eco-friendly vehicles that use electric power has been gradually increasing. In general, fuel economy and pollutant emissions of both conventional and eco-friendly vehicles are measured through chassis dynamometer tests that are performed on a variety of driving cycles before an actual driving test. There are a number of driving cycles that have been developed for the for performance evaluation of conventional vehicles. However, there is a lack of research into driving cycle for EV. Because large differences exist between the drive system and driving charateristics of EV and that of CV, a study on driving cycle for EV should be conducted. In this study, the necessity of an urban driving cycle for the performance evaluation of electric vehicles is confirmed by developing the driving cycle. First, the Gwacheon-city Urban Driving Cycle for Electric Vehicles (GUDC-EV) is developed by using driving data obtained through actual driving experiments and statistical analysis. Second, GUDC-EV is verified by constructing EV simulators and performing simulations that use the actual driving data. The simulation results are then compared against existing urban driving cycles, such as FTP-72, NEDC, and Japan 10–15. These results confirm that GUDC-EV can be used as an urban driving cycle to evaluate the performance of electric vehicles and validate the necessity of development of the driving cycle for electric vehicles. 相似文献
437.
Seung Hyun Kim 《运输规划与技术》2016,39(6):574-585
The delivery service provided by large-scale retailers continues to grow as online sales occupy an increasingly large share of the market. This study aims to tease out efficient vehicle scheduling times as well as optimal delivery routes by applying meta-heuristic algorithms. Monthly data on existing routes were obtained from a branch of Korea’s leading large-scale online retailer. The first task was to examine the status of existing routes by comparing delivery routes created using Dijkstra’s algorithm with existing delivery routes and their vehicle scheduling. The second task was to identify optimal delivery routes through a comparative analysis of the genetic algorithm and Tabu search algorithm, known for its superior applicability amongst other meta-heuristic algorithms. These findings demonstrate that the optimal vehicle routing problem not only has the potential to reduce distribution costs for operators and expedite delivery for consumers, but also the added social benefit of reduced carbon emissions. 相似文献
438.
The shipbuilding industry has adopted IT convergence as a new engine for growth encompassing conventional production know-how and economies of scale. Brand new solutions for enterprise IT, such as three-dimensional (3D) computer-aided design (CAD) systems, enterprise resource planning systems, and product lifecycle management systems have been adopted and customized to shipyards and contribute to productivity enhancement. As part of IT convergence in the shipbuilding industry, we examine the adoption of business process management (BPM) for the ship hull production design process. Ship hull production design, a process-based task, requires the most man-hours among all ship design processes and is directly coupled with ship production; thus, improvements in this task can contribute hugely toward enhancing productivity. First, we explain the concept of the executable model, which is an essential condition for executing defined processes in a business process management system (BPMS). In addition, we analyze the hull production design task and use this as the basis of a process to build executable BPM models. Thus, we present detailed implementations and the expected effects for the BPM execution of the hull production design process. The executable BPM model of the hull production design process is implemented using Bonita Open-Solution 5.5, a representative open-source BPMS. 相似文献
439.
In this paper, we propose a precise and reliable positioning method for solving common problems, such as a navigation satellite’s signal occlusion in an urban canyon and the positioning error due to a limited number of visible navigation satellites. This is an integrated system of the navigation satellites system and a vision system. In general, the navigation satellite positioning system has a fatal weakness in that it can not calculate a position coordinate when its signal is occluded by some obstacle. For this reason, positioning by using the navigation satellites system can not be used for a variety of applications. Therefore, we propose as a method to integrate both the navigation satellites system and the vision system. Some target objects that have accurate position coordinates, for example, in an outdoor shaded area like an urban canyon, are installed into the vision system. When the vision system recognizes a target object it loads the accurate coordinate of that target object. Then, it measures the distance by using the disparity from the camera sensor to the target object. These distance and object coordinate data are used for positioning with the navigation satellites system’s data. This integrated system can be used for the positioning solution where the user is in unfavorable conditions. This paper shows that the algorithm of integrated system and the numerical test performed. The results indicate that the reliable and stable positioning can be obtained by introducing the vision system to the satellite navigation system. 相似文献
440.
N. Kim H. Lohse-Busch A. Rousseau 《International Journal of Automotive Technology》2014,15(2):263-271
Owing to ever more stringent regulations and customers’ expectations, auto manufacturers have been considering numerous technology options to improve vehicle fuel economy. One of these is transmission technology, which has been shown to be one of the most cost-effective technologies. Over the past few years, transmissions have significantly evolved and have impacted both performance and fuel efficiency. As one of the advanced tranmissions, the dual clutch transmission (DCT) is the first automatic transmission to provide better efficiency than manual transmissions. DCTs provide reduced shift shocks and better driver comfort in addition to higher top speeds and torques. In this paper, a model and shifting controller for the DCT are developed in the vehicle systems context using Autonomie, a model-based vehicle simulation tool. Finally, the Autonomie DCT model and control strategy are validated using vehicle test data from Argonne’s Advanced Powertrain Research Facility. 相似文献