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[en] As the world’s top energy consumer, China is facing a great challenge to solve its energy supply issue. In this paper energy use from all industrial sectors in China’s economy of 2007 was explored by conducting an extended environmental input–output analysis. We compare the energy consumption embodied in the final demand for goods and services from 29 sectors with the energy demand required for the actual production process in each sector. Two different viewpoints for sectoral energy use have been presented: energy use is directly allocated to the producer entity, and energy use is reallocated to sector’s supply chain from consumption perspective. Our results show that considerable amount of energy use is embodied in the supply chain, especially for “Construction” and “Other Service Activities” sectors, which is not detected if energy use is allocated on a production basis. When further dividing embodied energy consumption into direct energy consumption and indirect energy consumption, total indirect energy consumption is much higher than that of total direct energy consumption, accounting for 80.6% of total embodied energy consumption in 2007. Our results provide a more holistic picture on sectoral energy consumption and therefore can help decision-makers make more appropriate policies. - Highlights: ► A hybrid IO-LCA model was employed to analyze China’s energy use at sectoral level. ► A case study on China’s sectoral energy consumption is done. ► Construction and service sectors are actually energy intensive from the supply chain perspectives. ► Upstream and downstream ectoral collaboration along the whole supply chain is necessary. ► Energy conservation policies should be based upon a comprehensive analysis on sectoral energy use.
[en] Energy-related CO2 emissions embodied in international trade have been widely studied by researchers using the environmental input-output analysis framework. It is well known that both sector aggregation and spatial aggregation affect the results obtained in such studies. With regard to the latter, past studies are often conducted at the national level irrespective of country or economy size. For a large economy with the needed data, studies may be conducted at different levels of spatial aggregation. We examine this problem analytically by extending the work of Su et al. ([Su, B., Huang, H.C., Ang, B.W., Zhou, P., 2010. Input-output analysis of CO2 emissions embodied in trade: The effects of sector aggregation. Energy Economics 32 (1), 166-175.]) on sector aggregation. We present a numerical example using the data of China and by dividing the country into eight regions. It is found that the results are highly dependent on spatial aggregation. Our study shows that for a large country like China it is meaningful to look into the effect of spatial aggregation. (author)
[en] A complex system of production links our greenhouse gas emissions to our consumer demands. Whilst progress may be made in improving efficiency, other changes in the production structure may easily annul global improvements. Utilising a structural decomposition analysis, a comparative-static technique of input-output analysis, over a time period of around 30 years, net greenhouse emissions are decomposed in this study into the effects, due to changes in industrial efficiency, forward linkages, inter-industry structure, backward linkages, type of final demand, cause of final demand, population affluence, population size, and mix and level of exports. Historically, significant competing forces at both the whole of economy and industrial scale have been mitigating potential improvements. Key sectors and structural influences are identified that have historically shown the greatest potential for change, and would likely have the greatest net impact. Results clearly reinforce that the current dichotomy of growth and exports are the key problems in need of address.
[en] Real-time spatial optimization - a combination of Geographical Information Science and Technology and Operations Research - is capable of generating optimized solutions to given spatial problems in real-time. The basic concepts to develop a real-time spatial optimization system are outlined in this thesis. Geographic Information Science delivers the foundations for acquiring, storing, manipulating, visualizing and analyzing spatial information. In order to develop a system that consists of several independent components the concept of Service Oriented Architectures is applied. This facilitates communication between software systems utilizing standardized services that ensure interoperability. Thus, standards in the field of Geographic Information are inevitable for real-time spatial optimization. By exploiting the ability of mobile devices to determine the own position paired with standardized services Location Based Services are created. They are of interest in order to gather real-time data from mobile devices that are of importance for the optimization process itself. To optimize a given spatial problem, the universe of discourse has to be modeled accordingly. For the problem addressed in this thesis - Wood Supply Chain management - Graph theory is used. In addition, the problem of Wood Supply Chain management can be represented by a specific mathematical problem class, the Vehicle Routing problem - specifically the Vehicle Routing Problem with Pickup and Delivery and Time Windows. To optimize this problem class, exact and approximate solution techniques exist. Exact algorithms provide optimal solutions and guarantee their optimally, whereas approximate techniques - approximation algorithms or heuristics - do not guarantee that a global optimum is found. Nevertheless, the are capable of handling large problem instances in reasonable time. For optimizing the Wood Supply Chain Adaptive Large Neighborhood Search is selected as appropriate optimization technique - which is an approximate algorithm. Spatial Decision Support Systems are software systems that are able to support a decision maker an a complex, semi-structured problem. Through the fact that Wood Supply Chain management can be regarded as a semi-structured problem, it is feasible to solve this task with the help of such a system. The decision maker is able to influence the results of a Decision Support System, either by selecting one of the system's recommendations or by the input of preferences and additional criteria. A combination of all three fields of expertise - Geographic Science and Technology, Operations Research and Spatial Decision Support Systems results in a system that is capable of providing decision support for Wood Supply Chain management by real-time spatial optimization. Hence, relevant data are collected in real-time, and optimal routes for each truck are calculated for a specified planning horizon. With the help of such a system, timber - after it is piled up in the forest - is dynamically allocated (and thus dynamically 'solid') to saw mills. Subsequently the routes of each vehicle are calculated so that the overall profit is maximized - i.e. timber sales minus haulage costs. For proving the feasibility of this concept a prototype is developed, and two test instances are created. These test instances are optimized using the prototype at hand followed by an evaluation of the obtained results. (author)
[de]Mir räumlicher Optimierung in Echtzeit, die eine Kombination von Geographic Information Science und Technology sowie Operations Research darstellt, ist es möglich räumliche Problemstellungen in Echtzeit zu optimieren. Die grundlegenden Konzepte um ein System zur Echtzeit Optimierung von räumlichen Problemen aufzubauen werden in dieser vorliegenden Arbeit behandelt. Das Fachgebiet Geographic Information Science liefert die Grundlagen zur Erfassung, Speicherung, Manipulation, Visualisierung und Analyse von geographischer Information. Um ein System zu entwickeln, welches aus mehreren unabhängigen Komponenten besteht, kann das Konzept der Service orientierten Architekturen angewandt werden. Es ermöglicht die Kommunikation zwischen Softwaresystemen mittels standardisierter Servieves, die Interoperabilität gewährleisten. Deshalb sind Standards - vor allem jene aus dem Gebiet der Geoinformation - wichtig für die Enwicklung eines räumlichen Optimierungssystems. Durch die Kombination von mobilen Endgeräten, wie PDA's oder Smartphones - die vermehrt die Möglichkeiten haben ihre Position festzustellen - sowie sowie standartisierter Services, entstehen ortsbezogene Dienste (Location Based Services). Diese Services sind für die Sammlung von Echtzeitdaten von mobilen Geräten unabdingbar, was für den Optimierungsprozess von großer Bedeutung ist. Um ein gegebenes räumliches Problem zu optimieren ist es notwendig die zu untersuchende Aufgabenstellung zu modellieren. Im Zuge dieser Arbeit wird die Logistikkette Holz durch eine spezielle mathematische Problemklasse - dem Vehicle Routing Problem - repräsentiert werden. Im Speziellen handelt es sich um das Vehicle Routing Problem mit Pickup und Delivery und Time Windows. Um diese Problemklasse zu optimieren gibt es exakte und approximative Algorithmen. Exakte Techniken garantieren die Optimalität der gefundenen Lösungen, während approximative Technike - Approximationsalgorithmen und Heuristiken - keine global beste Lösung garantieren. Trotzdem können die beiden letztgenannten Techniken mit großen Probleminstanzen umgehen. Um die Logistikkette Holz zu optimieren wurde Adaptive Large Neighborhood Search als probate Optimierungstechnik ausgewählt - was eine approximative Technik darstellt. Spatial Decision Support Systeme sind software-basierte Systeme die Entscheidungsträger bei komplexen, semi-strukturierten Problemen unterstützen. Da die Logistikkette Holz als semi-strukturiertes Problem angesehen werden kann, erscheint es sinnvoll solch eine Aufgabe mittels Spatial Decision Support Systemen zu lösen. Die Entscheidungsträger können das Ergebnis des Decision Support Systems durch die Auswahl einer Empfehlung des Systems oder durch die Eingabe von Präferenzen und weiteren Entscheidungskriterien beeinflussen. Durch die Kombinationen der drei Fachgebiete - Geographic Information Science und Technology, Operations Research und Spatial Decision Support Systemen - kann ein Systen entwickelt werden, das Entscheidungsunterstützung für die Logistikkette Holz durch räumliche Optimierung bietet. Die Daten, die für die Optimierung von Bedeutung sind, werden in Echtzeit gesammelt und in der Folge werden für einen definierten Planungshorizont optimale Routen für jeden LKW berechnet. Dadurch ist es möglich, Holz - nachdem es im Wald auf einem Polter gestapelt wurde - dynamisch Sägewerken zuzuweisen, wodurch der Verkaufsprozess eigentlich zustande kommt. Die Routen werden so berechnet, dass der globale Profit der Logistikkette maximiert wird - d.h. Erlöse aus dem Holzverkauf minus Transportkosten. Um zu zeigen, dass ein solches System funktioniert werden ein Prototyp, sowie zwei Instanzen von Testdaten erstell. Diese Testdaten werden mit dem entwickelten System optimiert und in weiterer Folge evaluiert. (author)
[en] It is generally believed that index decomposition analysis (IDA) and input-output structural decomposition analysis (SDA) [Rose, A., Casler, S., Input-output structural decomposition analysis: a critical appraisal, Economic Systems Research 1996; 8; 33-62; Dietzenbacher, E., Los, B., Structural decomposition techniques: sense and sensitivity. Economic Systems Research 1998;10; 307-323] are different approaches in energy studies; see for instance Ang et al. [Ang, B.W., Liu, F.L., Chung, H.S., A generalized Fisher index approach to energy decomposition analysis. Energy Economics 2004; 26; 757-763]. In this paper it is shown that the generalized Fisher approach, introduced in IDA by Ang et al. [Ang, B.W., Liu, F.L., Chung, H.S., A generalized Fisher index approach to energy decomposition analysis. Energy Economics 2004; 26; 757-763] for the decomposition of an aggregate change in a variable in r = 2, 3 or 4 factors is equivalent to SDA. They base their formulae on the very complicated generic formula that Shapley [Shapley, L., A value for n-person games. In: Kuhn H.W., Tucker A.W. (Eds), Contributions to the theory of games, vol. 2. Princeton University: Princeton; 1953. p. 307-317] derived for his value of n-person games, and mention that Siegel [Siegel, I.H., The generalized 'ideal' index-number formula. Journal of the American Statistical Association 1945; 40; 520-523] gave their formulae using a different route. In this paper tables are given from which the formulae of the generalized Fisher approach can easily be derived for the cases of r = 2, 3 or 4 factors. It is shown that these tables can easily be extended to cover the cases of r = 5 and r = 6 factors. (author)
[en] The indirect carbon emission embodied in the intermediate input is also an important indicator of assessing a producer’s carbon emissions. Structural analysis of indirect carbon emissions is helpful to understand the responsibilities between producers and pay efforts to key areas. The aim of this study is to analyze indirect carbon emissions embodied in intermediate input between sectors and explore the distribution structure of indirect carbon emissions flow network (namely, ICEFN). Based on the modified input-output model and complex network theory, this study constructed four directed and weighted ICEFNs with 28 sectors from 1997 to 2012. The results show that indirect carbon emissions between sectors are significantly higher than direct carbon emissions, accounting for nearly 70% of the total carbon emissions of China. Second, we analyzed the embodied carbon emission intensity (namely, ECI) of each sector. Although the ECI has been decreasing over time, the decrease has increasingly diminished, which indicates that the additional carbon emission reductions are more difficult. Third, we identified the key sectors which play different roles in the ICEFNs. Meanwhile, we studied the key paths which show more closed relationships between some sectors in ICEFNs. Finally, based on the above analysis, we made policy recommendations.
[en] Highlights: • Novel framework integrates monetary and physical changes in sequential input–output analysis. • Estimate economy-wide environmental changes as a result of combined energy policies. • Life cycle resource consumption and emission data for the U.S. economic sectors are adopted. • Ecosystem impacts could increase as a consequence of combined gasoline tax and bio-subsidy. - Abstract: A novel generic sequential input–output framework is developed to model the economy-wide changes in resource consumption and environmental emissions as a result of combined applied energy policies, e.g. taxes for non-renewables and subsidies for renewables. Many input–output analyses are based on a single period analysis. However, in the case of analyzing the effects of multiple policy interventions over time, the input–output table reflecting the state of the economy before the energy policy was introduced cannot be used for analyzing the economic effects of another policy intervention in the next time period since the monetary and physical transaction of commodities have already been affected. To show the efficacy of the proposed method, a case study is developed that introduced a gasoline tax and earmarks the revenues to subsidize biofuel production in the subsequent time period in the United States. In order to assess the change of environmental indicators after sequential policy interventions, Ecologically-based Life Cycle Analysis (ECO-LCA) inventories which include data on resource consumption, emissions, ecosystem goods and services related to the U.S. economic sectors are adopted. The environmentally extended input–output framework is ideally suited to model the interlinkages between a range for environmental indicators and detailed structural economic information at the sector level for the analysis of energy policies. The proposed framework can be utilized as a tool for leveraging the energy and environmental policy trade-off decisions which consider the impacts to resource consumption and environmental emissions. Our results show that, if a share of the gasoline tax revenue is reinvested to subsidize biofuel production, economy wide resource consumptions and emissions from the fossil fuel related supply chains will decrease. However, ecosystem goods and services such as soil erosion, water consumption for agricultural and livestock, cropland, nitrogen deposition along with the emissions such as nitrous oxide and ammonia will increase in short term as a consequence of the price drop and the increased demand for biofuels. This emphasizes the importance of focusing on a wide range of environmental outcomes and unintended side effects when introducing a specific environmental policy.
[en] An optimization problem of minimizing the output load of a junction model with multiple input and output channels is solved by the replica method. Simulation results show that for the case of extensive connectivity, the replica solution obtained by assuming a vanishing solution space is satisfactory. However, for the case of intensive connectivity, the degeneracy of the solution space causes the simulation results to deviate from the replica solution of vanishing volume. (author). Letter-to-the-editor
[en] This paper presents an adaptive fuzzy control scheme for a class of continuous-time single-input single-output nonlinear systems with unknown dynamics and disturbance. Within this scheme, the fuzzy systems are employed to approximate the unknown system's dynamics. The proposed controller is composed of a well-defined adaptive fuzzy control term that uses the adaptive fuzzy approximation errors and disturbance. Based on a Lyapunov synthesis method, it is shown that the proposed adaptive control scheme guarantees the convergence of the tracking error to zero and the global boundedness of all signals in the closed-loop system. Moreover, the proposed controller allows initialization by zero of all adjusted parameters in the fuzzy approximators, and does not require the knowledge of the lower bound of the control gain and upper bounds of the approximation errors and disturbance. Simulation results performed on an inverted pendulum system are given to point out the good performance of the developed adaptive controller. (author)