| 1. |
- Gren, Åsa, et al.
(författare)
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How smart is smart growth? : Examining the environmental validation behind city compaction
- 2019
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Ingår i: Ambio. - : Springer Netherlands. - 0044-7447 .- 1654-7209. ; 48:6, s. 580-589
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Forskningsöversikt (refereegranskat)abstract
- Smart growth (SG) is widely adopted by planners and policy makers as an environmentally friendly way of building cities. In this paper, we analyze the environmental validity of the SG-approach based on a review of the scientific literature. We found a lack of proof of environmental gains, in combination with a great inconsistency in the measurements of different SG attributes. We found that a surprisingly limited number of studies have actually examined the environmental rationales behind SG, with 34% of those studies displaying negative environmental outcomes of SG. Based on the insights from the review, we propose that research within this context must first be founded in more advanced and consistent knowledge of geographic and spatial analyses. Second, it needs to a greater degree be based on a system's understanding of urban processes. Third, it needs to aim at making cities more resilient, e.g., against climate-change effects.
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| 2. |
- Ljunggren Söderman, Maria, 1967, et al.
(författare)
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Integrated Economic and Environmental Assessment of Waste Policy Instruments
- 2016
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Ingår i: Sustainability. - : MDPI AG. - 2071-1050. ; 8:5
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Tidskriftsartikel (refereegranskat)abstract
- The need for new policy instruments supporting the on-going transition from end-of-pipe waste treatment to resource management has been recognized in European policy. Instruments need to be carefully assessed before implementation to promote the desired changes and avoid problem shifting. Mathematical models may assist policy makers in such assessments. This paper presents a set of soft-linked models for assessing the economic and environmental impacts of policy instruments for both the prevention and management of waste and discusses its strengths and limitations. Consisting of (1) a macro-economic model, (2) a systems engineering model for waste management and (3) a life cycle assessment model for waste management, the set is primarily suited to assessing market-based instruments and environmental regulations. Considerable resources were needed for developing and using the set, and there are clear limits as to what can be addressed. However, if only one of the models had been used, neither the range of instruments nor the scope of impacts would have been possible to cover. Furthermore, soft-linked models allow many disciplines to contribute within one harmonized framework. Such integrated assessments may become increasingly useful for continuing the implementation of policy for sustainable governance of society's material resources.
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| 3. |
- Zhang, Chen, et al.
(författare)
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Resilient cooling strategies – A critical review and qualitative assessment
- 2021
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Ingår i: Energy and Buildings. - : Elsevier BV. - 0378-7788 .- 1872-6178. ; 251
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Tidskriftsartikel (refereegranskat)abstract
- The global effects of climate change will increase the frequency and intensity of extreme events such as heatwaves and power outages, which have consequences for buildings and their cooling systems. Buildings and their cooling systems should be designed and operated to be resilient under such events to protect occupants from potentially dangerous indoor thermal conditions. This study performed a critical review on the state-of-the-art of cooling strategies, with special attention to their performance under heatwaves and power outages. We proposed a definition of resilient cooling and described four criteria for resilience—absorptive capacity, adaptive capacity, restorative capacity, and recovery speed —and used them to qualitatively evaluate the resilience of each strategy. The literature review and qualitative analyses show that to attain resilient cooling, the four resilience criteria should be considered in the design phase of a building or during the planning of retrofits. The building and relevant cooling system characteristics should be considered simultaneously to withstand extreme events. A combination of strategies with different resilience capacities, such as a passive envelope strategy coupled with a low-energy space-cooling solution, may be needed to obtain resilient cooling. Finally, a further direction for a quantitative assessment approach has been pointed out.
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| 4. |
- Fritzin, Jonas, et al.
(författare)
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Linearity, intermodulation distortion and ACLR in outphasing amplifiers
- 2013
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Ingår i: 2013 IEEE MTT-S International Microwave Symposium Digest. - : IEEE conference proceedings. - 0149-645X. - 9781467361767 - 9781467321419
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Konferensbidrag (refereegranskat)abstract
- The distortion from amplitude and phase imbalance in outphasing amplifiers is discussed. The relation between dynamic range (DR) and suppression of distortion is shown to approximately follow a simple linear relationship depending on the DR. Approximate relations between adjacent channel leakage power ratio (ACLR) for different kinds of commonly used communication signals and two-tone intermodulation distortion are given. Relations between loss in output power and reduction of DR as functions of duty cycle in switching-based outphasing amplifiers are also given. An approximate method to evaluate the possible performance of digital pre-distortion (DPD) is also given by considering a DPD capable of correcting all distortions except amplitude imbalance. The predicted performance is compared to the performance obtained using a DPD-model found in the literature. The results show that the method is in good agreement, demonstrating that the proposed method can be used for design and evaluation of predistorted outphasing amplifiers.
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| 5. |
- Landin, Per, et al.
(författare)
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Behavioral modeling of outphasing amplifiers considering memory effects
- 2013
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Ingår i: 2013 IEEE MTT-S International Microwave Symposium Digest. - : IEEE conference proceedings. - 0149-645X. - 9781467361767
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Konferensbidrag (refereegranskat)abstract
- This paper proposes a behavioral model structure for outphasing amplifiers. The model performance is evaluated on a class-D CMOS outphasing amplifier and compared with two models found in the literature. The proposed model structure also allows the use of memory in a parallel Hammerstein-like setting. The proposed models show improvements in adjacent channel error power ratio (ACEPR) of approximately 5 dB in addition to being linear in the parameters. The lower model errors enable the use and design of improved predistorters taking frequency dependency (memory effects) in outphasing amplifiers into account.
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| 6. |
- Landin, Per N., et al.
(författare)
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Two novel memory polynomial models for modeling of RF power amplifiers
- 2015
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Ingår i: International journal of microwave and wireless technologies. - 1759-0795 .- 1759-0787. ; 7:1, s. 19-29
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Tidskriftsartikel (refereegranskat)abstract
- Two novel memory polynomial models are derived based on physical knowledge of a general power amplifier (PA). The derivations are given in detail to facilitate derivations of other model structures. The model error in terms of normalized mean square error (NMSE) and adjacent channel error power ratio (ACEPR) of the novel model structures are compared to that of established models based on the number of parameters using data measured on two different amplifiers, one high-power base-station PA and one low-power general purpose amplifier. The novel models show both lower NMSE and ACEPR for any chosen number of parameters compared to the established models. The low model errors make the novel models suitable candidates for both modeling and digital predistortion.
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| 7. |
- Jonasson, Karl, et al.
(författare)
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Time and Scale Aspects in Life Cycle Assessment of Emerging Technologies: Case Study on Alternative Transport Fuels
- 2004
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Life cycle assessments (LCAs, including well-to-wheel studies) that are to support decisions that strive to change large technical systems need to consider time- and scale-related factors that are given little attention in standard LCA procedures. We suggest that it is important to look beyond the current situation and study many possible future states, what we call stylised states, to explore general technology differences. We choose to address three issues in this report. Our case study deals with alternative fuels for transportation, and relates to a recent well-to-wheel study performed by CONCAWE, EUCAR and JRC. The methodological results, though, could be of equal importance when studying other major technologies.First, shifting time frame gives room for technical development that should affect not only the choice of performance data, but perhaps also the functional unit and the selection of technologies under study.Second, background systems such as heat and power production change over time, and we exemplify by using three different systems, mainly based on coal, natural gas and short rotation forestry, respectively. Increased production volumes may for some technologies also change the background system, which is of particular importance for technologies that are used in their own production processes. We show that for biofuels changes in background systems have consequences not only for greenhouse gas (GHG) emissions and agricultural land use for each fuel chain, but also for the ranking order of e.g. wheat ethanol and RME, in terms of GHG emissions. We use what we call a net output approach, which implies that a fraction of the produced biofuel is used for its own production. Accordingly, the functional unit used in this study is 1 MJ fuel available for other purposes than producing fuel.Finally, different types of feedstock are available in different quantities and different by-product markets vary in size. Allocation of environmental impact between product and by-products is here made through system expansion, and we study some possible markets for by-products. To give an example of by-product effects, current key markets for ethanol by-products in EU-15 correspond to an ethanol production that covers about 2 % of demand, and for RME about 3 %, that is, well below the 5.75 % EU biofuel target for 2010. Therefore, the GHG emissions and agricultural land use allocated to the fuels differ between a low and a high market penetration.Combining the results, we show that time and scale are important factors for the ranking of wheat ethanol, RME and wood methanol in terms of GHG emissions and agricultural land use, as the results are dependent on assumptions regarding background system and by-product markets. We indicate that agricultural land use results can be weighted in GHG terms in several ways, e.g. by using short rotation forestry or solar panels as a reference, an approach that would require further research.
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| 8. |
- Soltani Tehrani, Ali, 1982, et al.
(författare)
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A Comparative Analysis of the Complexity/Accuracy Tradeoff in Power Amplifier Behavioral Models
- 2010
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Ingår i: IEEE transactions on microwave theory and techniques. - 0018-9480 .- 1557-9670. ; 58:6, s. 1510-1520
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Tidskriftsartikel (refereegranskat)abstract
- A comparative study of state-of-the-art behavioral models for microwave power amplifiers (PAs) is presented in this paper. After establishing a proper definition for accuracy and complexity for PA behavioral models, a short description on various behavioral models is presented. The main focus of this paper is on the modeling accuracy as a function of computational complexity. Data is collected from measurements on two PAs-a general-purpose amplifier and a Doherty PA designed for WiMAX-for different output power levels. The models are characterized in terms of accuracy and complexity for both in-band and out-of-band error. The results show that, among the models studied, the generalized memory polynomial behavioral model has the best tradeoff for accuracy versus complexity for both PAs, and can obtain high performance at half of the computational cost of all other models analyzed.
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| 9. |
- Finnveden, Göran, et al.
(författare)
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Policy instruments towards a sustainable waste management
- 2013
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Ingår i: Sustainability. - Basel : MDPI AG. - 2071-1050. ; 5:3, s. 841-881
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this paper is to suggest and discuss policy instruments that could lead towards a more sustainable waste management. The paper is based on evaluations from a large scale multi-disciplinary Swedish research program. The evaluations focus on environmental and economic impacts as well as social acceptance. The focus is on the Swedish waste management system but the results should be relevant also for other countries. Through the assessments and lessons learned during the research program we conclude that several policy instruments can be effective and possible to implement. Particularly, we put forward the following policy instruments: “Information”; “Compulsory recycling of recyclable materials”; “Weight-based waste fee in combination with information and developed recycling systems”; “Mandatory labeling of products containing hazardous chemicals”, “Advertisements on request only and other waste minimization measures”; and “Differentiated VAT and subsidies for some services”. Compulsory recycling of recyclable materials is the policy instrument that has the largest potential for decreasing the environmental impacts with the configurations studied here. The effects of the other policy instruments studied may be more limited and they typically need to be implemented in combination in order to have more significant impacts. Furthermore, policy makers need to take into account market and international aspects when implementing new instruments. In the more long term perspective, the above set of policy instruments may also need to be complemented with more transformational policy instruments that can significantly decrease the generation of waste.
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| 10. |
- Malmqvist, Tove, et al.
(författare)
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A Swedish environmental rating tool for buildings
- 2011
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Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 36:4, s. 1893-1899
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Tidskriftsartikel (refereegranskat)abstract
- In 2003, a joint effort between the Swedish government, a number of companies in the building and construction sectors, some municipalities, insurance companies and banks set a target that by 2009, all new buildings and 30% of existing Swedish buildings should be rated using a voluntary environmental rating tool. In a major research programme finished in 2008, a tool was developed to be used in this context. The tool covers three assessment areas: Energy, Indoor environment and Material & Chemicals. These areas are split into 11 aspects with one or a few indicators. Rating criteria are specified for each indicator, stipulating requirements for a rating Gold, Silver, Bronze and Rated. Indicator results can then be aggregated to aspect, area and a single raring for building level for enhanced result communication. The tool builds on previous experiences regarding environmental building rating tools and therefore includes some special characteristics which aim to tackle some of the criticism directed towards the first generation of such tools. At the time of writing, the first buildings have received official ratings and an independent stakeholder group is promoting broader implementation of the tool. (C) 2010 Elsevier Ltd. All rights reserved.
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