1,821 research outputs found
Why are Market Economies Politically Stable? A Theory of Capitalist Cohesion
The present paper documents that political stability is positively associated with the extent of domestic trade. In explaining this regularity, we provide a model where political cohesion is linked to the emergence of a fully functioning market economy. Without market exchange, the welfare of inherently selfish individuals will be mutually independent. As a result, political negotiations, echoing the preferences of the citizens of society, will be dog-eat-dog in nature. Whoever has greater bargaining power will be willing to make decisions that enhance the productivity of his supporters at the expense of other groups in society. If the gains from specialization become sufficiently large, however, a market economy will emerge. From being essentially non-cooperative under self-sufficiency, the political decision making process becomes cooperative in the market economy, as the welfare of individuals will be mutually interdependent due to the exchange of goods
Why are Rich Countries more Politically Cohesive?
We document empirically that rich countries are more politically cohesive than poorer countries. In order to explain this regularity, we provide a model where political cohesion is linked to the emergence of a fully functioning market economy. Without market exchange, the welfare of inherently selfish individuals will be mutually independent. As a result, political negotiations, echoing the preferences of the citizens of society, will be dog-eat-dog in nature. Whoever has greater bargaining power will be willing to make decisions that enhance the productivity of his supporters at the expense of other groups in society. If the gains from specialization become sufficiently large, however, a market economy will emerge. From being essentially non-cohesive under self-sufficiency, the political decision making process becomes cohesive in the market economy, as the welfare of individuals will be mutually interdependent due to the exchange of goods. We refer to this latter state as “capitalist cohesion”.political cohesion; economic growth
On the non-linearity of the willingness to commute
Established analysis of labour market commuting are based on random choice models and gravity type models. In these models generalised transport costs are formulated as exponential or loglinear distance-dependent functions. This paper presents empirical observations that imply that time-distances influence the commuting behaviour in a non-linear way, such that the time sensitivity is much lower for very short and long distances, whereas intermediate distance display a high time sensitivity. This is explained in a model which is parametrised and estimated. The results are important for understanding and predicting commuter behaviour. It also helps to delineate space, as in classical traditions, into local, intra-regional, and extra-regional space.
Estimation of 3D vegetation structure from waveform and discrete return airborne laser scanning data
This study presents and compares new methods to describe the 3D canopy structure with Airborne Laser Scanning (ALS) waveform data as well as ALS point data. The ALS waveform data were analyzed in three different ways; by summing the intensity of the waveforms in height intervals (a); by first normalizing the waveforms with an algorithm based on Beer-Lambert law to compensate for the shielding effect of higher vegetation layers on reflection from lower layers and then summing the intensity (b); and by deriving points from the waveforms (c). As a comparison, conventional, discrete return ALS point data from the laser scanning system were also analyzed (d). The study area was located in hemi-boreal, spruce dominated forest in the southwest of Sweden (Lat. 58° N, Long. 13° E). The vegetation volume profile was defined as the volume of all tree crowns and shrubs in 1 dm height intervals in a field plot and the total vegetation volume as the sum of the vegetation volume profile in the field plot. The total vegetation volume was estimated for 68 field plots with 12 m radius from the proportion between the amount of ALS reflections from the vegetation and the total amount of ALS reflections based on Beer-Lambert law. ALS profiles were derived from the distribution of the ALS data above the ground in 1 dm height intervals. The ALS profiles were rescaled using the estimated total vegetation volume to derive the amount of vegetation at different heights above the ground. The root mean square error (RMSE) for cross validated regression estimates of the total vegetation volume was 31.9% for ALS waveform data (a), 27.6% for normalized waveform data (b), 29.1% for point data derived from the ALS waveforms (c), and 36.5% for ALS point data from the laser scanning system (d). The correspondence between the estimated vegetation volume profiles was also best for the normalized waveform data and the point data derived from the ALS waveforms and worst for ALS point data from the laser scanning system as demonstrated by the Reynolds error index. The results suggest that ALS waveform data describe the volumetric aspects of vertical vegetation structure somewhat more accurately than ALS point data from the laser scanning system and that compensation for the shielding effect of higher vegetation layers is useful. The new methods for estimation of vegetation volume profiles from ALS data could be used in the future to derive 3D models of the vegetation structure in large areas
Species-specific forest variable estimation using non-parametric modeling of multi-spectral photogrammetric point cloud data
The recent development in software for automatic photogrammetric processing of multispectral aerial imagery, and the growing nation-wide availability of Digital Elevation Model (DEM) data, are about to revolutionize data capture for forest management planning in Scandinavia. Using only already available aerial imagery and ALS-assessed DEM data, raster estimates of the forest variables mean tree height, basal area, total stem volume, and species-specific stem volumes were produced and evaluated. The study was conducted at a coniferous hemi-boreal test site in southern Sweden (lat. 58° N, long. 13° E). Digital aerial images from the Zeiss/Intergraph Digital Mapping Camera system were used to produce 3D point-cloud data with spectral information. Metrics were calculated for 696 field plots (10 m radius) from point-cloud data and used in k-MSN to estimate forest variables. For these stands, the tree height ranged from 1.4 to 33.0 m (18.1 m mean), stem volume from 0 to 829 m3 ha-1 (249 m3 ha-1 mean) and basal area from 0 to 62.2 m2 ha-1 (26.1 m2 ha-1 mean), with mean stand size of 2.8 ha. Estimates made using digital aerial images corresponding to the standard acquisition of the Swedish National Land Survey (Lantmäteriet) showed RMSEs (in percent of the surveyed stand mean) of 7.5% for tree height, 11.4% for basal area, 13.2% for total stem volume, 90.6% for pine stem volume, 26.4 for spruce stem volume, and 72.6% for deciduous stem volume. The results imply that photogrammetric matching of digital aerial images has significant potential for operational use in forestry
Marking of roundwood : information transfer, measurements opportunities and marking methodology in the timber flow from forest to industry
Stora kvantiteter data produceras varje dag i de svenska skogarna. Allt från taxeringsdata och skördarmätt data till uppskattade data vid virkestransporter och data från inmätningen vid industrierna. En stor del av det data som samlas in under tidiga skeden i flödeskedjan når aldrig industrierna utan förblir kvar i traktbanken eller skogsbruksplanerna hos skogsägarna. Detta är till stor del information som skulle kunna användas till att optimera respektive delprocess i hela flödeskedjan och som dessutom uppskattas eller mäts flera gånger under tiden virket går genom processerna. Virket identitetsmärks på avlägget med hjälp av vältlappar i södra Sverige eller en färgad sifferstämpling i norra Sverige. Dessa två manuella märkningsmetoder innebär en del problem som främst kopplades till den mänskliga faktorn eller väderförhållanden, vilket senare skapar extraarbete för personer i följande steg i kedjan.
Syftet med studien var att undersöka potentialen för ett digitalt spårningssystem för virke genom att beskriva dagens märkningsmetoder med de kostnader och problem som de står för och kartlägga det informationsflöde som sker idag och samtidigt undersöka vilka effekter ett digitalt informationssystem skulle kunna innebär för olika funktioner inom flödeskedjan – från skog till industri.
Kvalitativa intervjuer av olika representanter från skogsbruket genomfördes för att samla in information om märkningsmetoderna och vilka effekter ett ökat informationsflöde angående virket skulle innebära för respektive process. Intervjuerna genomfördes även för att visualisera dagens informationsflöde med hjälp av processkartläggning. Även enklare kostnadsberäkningar av märkningsmetoderna utfördes med insamlad tiddata från skotarförarnas självskattning av den tid de nyttjar till märkningen för att skapa en bild av en möjlig besparingspotential.
Huvudresultatet av studien visade att mycket data registreras flera gånger under vägen från stående skog till inmätning på industrin. Som mest registrerades virkets volym vid sex olika tillfällen. Intervjuerna resulterade i att märkningen tog mellan 8–24 minuter per skift att utföra, och något kortare tid för märkning med vältlappar än med stämpling. Detta skulle generera en märkningskostnad på mellan 0,15–4,13 kr/m3fub beroende på märkningsmetod, avverkningsform och vilken timkostnad som används i beräkningarna.
Slutsatsen är att det finns potential för en digitalt sammanhållen spårning av virke på grund av efterfrågan på ökad information av virkesdata från industrierna och ett fortsatt intresse av virkets geografiska spårbarhet. Inga slutsatser kring den faktiska ekonomiska besparingspotentialen kan dras innan fler studier med noggranna tidsstudier och beräkningar av den faktiska besparingspotentialen utförs.Large amounts of data are produced every day in the Swedish forestry; from forest inventory data and harvester measured data to estimated data for timber transports and data from the measurement at the industries. A large part of the data collected during the early stages of the supply chain never reaches the receiving industries but remains in the stand register or forestry plans of the forest owners. This is information that could be used to optimize each sub-process in the entire supply chain, which is also estimated or measured several times while the timber goes through the processes. The logs are marked on the landings with marking tags in southern Sweden or a colored number stamp in northern Sweden. These two manual marking methods involve some problems that are mainly linked to the human factor or weather conditions, which later creates extra work for people in the following steps in the chain.
The purpose of the study was to investigate the potential for a digital tracking system for timber by describing current marking methods with the costs and problems they face and map the information flow that takes place today and at the same time investigate what effects a digital information system could have for the various functions within the supply chain - from forest to industry.
The qualitative interviews of various representatives from forestry were conducted to gather information about the marking methods and what effects an increased flow and quality of data about the timber would have in their respective processes and to visualize the current information flow with the help of process mapping. A simple cost calculation of the marking methods was performed with collected time data from forwarder drivers' self-assessment of the time they used for timber marking, to create a picture of a possible saving potential.
The main results of the study showed that a lot of data is registered several times along the way from standing forest to measurement at industry. At most, the volume of the timber was registered on six different occasions. The interviews resulted in the marking taking between 8–24 minutes per work shift to perform, with slightly shorter time for marking with marking tags than with stamping. This would generate a marking cost of between 0.15–4.13 SEK/m3fub depending on if its thinning or final felling, the marking method and the hourly cost used in the calculations.
The conclusion is that there is potential for digitally coherent tracking of timber due to the demand for increased information of timber data from industries and a continued interest in the geographical traceability of timber. No conclusions about the actual economic savings potential can be drawn before more studies with careful time studies and calculations of the actual savings potential are performed
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