Just-for-Me: An Adaptive Personalization System for Location-Aware Social Music Recommendation

The fast growth of online communities and increasing pop-ularity of internet-accessing smart devices have significantly changed the way people consume and share music. As an emerging technology to facilitate effective music retrieval on the move, intelligent recommendation has been recently re-ceived great attentions in recent years. While a large amount of efforts have been invested in the field, the technology is still in its infancy. One of the major reasons for this stagna-tion is due to inability of the existing approaches to compre-hensively take multiple kinds of contextual information into account. In the paper, we present a novel recommender sys-tem called Just-for-Me to facilitate effective social music rec-ommendation by considering users ’ location related contexts as well as global music popularity trends. We also develop an unified recommendation model to integrate the contex-tual factors as well as music contents simultaneously. Fur-thermore, pseudo-observations are proposed to overcome the cold-start and sparsity problems. An extensive experimental study based on different test collections demonstrates that Just-for-Me system can significantly improve the recommen-dation performance at various geo-locations

Soil Respiration in Tibetan Alpine Grasslands: Belowground Biomass and Soil Moisture, but Not Soil Temperature, Best Explain the Large-Scale Patterns

The Tibetan Plateau is an essential area to study the potential feedback effects of soils to climate change due to the rapid rise in its air temperature in the past several decades and the large amounts of soil organic carbon (SOC) stocks, particularly in the permafrost. Yet it is one of the most under-investigated regions in soil respiration (Rs) studies. Here, Rs rates were measured at 42 sites in alpine grasslands (including alpine steppes and meadows) along a transect across the Tibetan Plateau during the peak growing season of 2006 and 2007 in order to test whether: (1) belowground biomass (BGB) is most closely related to spatial variation in Rs due to high root biomass density, and (2) soil temperature significantly influences spatial pattern of Rs owing to metabolic limitation from the low temperature in cold, high-altitude ecosystems. The average daily mean Rs of the alpine grasslands at peak growing season was 3.92 µmol CO2 m−2 s−1, ranging from 0.39 to 12.88 µmol CO2 m−2 s−1, with average daily mean Rs of 2.01 and 5.49 µmol CO2 m−2 s−1 for steppes and meadows, respectively. By regression tree analysis, BGB, aboveground biomass (AGB), SOC, soil moisture (SM), and vegetation type were selected out of 15 variables examined, as the factors influencing large-scale variation in Rs. With a structural equation modelling approach, we found only BGB and SM had direct effects on Rs, while other factors indirectly affecting Rs through BGB or SM. Most (80%) of the variation in Rs could be attributed to the difference in BGB among sites. BGB and SM together accounted for the majority (82%) of spatial patterns of Rs. Our results only support the first hypothesis, suggesting that models incorporating BGB and SM can improve Rs estimation at regional scale

No depth-dependence of fine root litter decomposition in temperate beech forest soils

Aims Subsoil organic carbon (OC) tends to be older and is presumed to be more stable than topsoil OC, but the reasons for this are not yet resolved. One hypothesis is that decomposition rates decrease with increasing soil depth. We tested whether decomposition rates of beech fine root litter varied with depth for a range of soils using a litterbag experiment in German beech forest plots. Methods In three study regions (Schorfheide-Chorin, Hainich-Dün and Schwäbische-Alb), we buried 432 litterbags containing 0.5 g of standardized beech root material (fine roots with a similar chemical composition collected from 2 year old Fagus sylvatica L. saplings, root diameter<2mm) at three different soil depths (5, 20 and 35 cm). The decomposition rates as well as the changes in the carbon (C) and nitrogen (N) concentrations of the decomposing fine root litter were determined at a 6 months interval during a 2 years field experiment. Results The amount of root litter remaining after 2 years of field incubation differed between the study regions (76 ± 2 % in Schorfheide-Chorin, 85 ± 2 % in Schwäbische-Alb, and 88±2 % in Hainich-Dün) but did not vary with soil depth. Conclusions Our results indicate that the initial fine root decomposition rates are more influenced by regional scale differences in environmental conditions including climate and soil parent material, than by changes in microbial activities with soil depth. Moreover, they suggest that a similar potential to decompose new resources in the form of root litter exists in both surface and deep soils

Democratization, Quality of Institutions and Economic Growth

There are two innovations in the paper as compared to the previous literature on democracy and growth. First, we consider not only the level of democracy, but also changes in this level in the 1970s-1990s as measured by increments of Freedom House political rights indices. Second, the distinction is made between democracy and law and order (order based on legal rules); the latter is measured by the rule of law, investors' risk and corruption indices. We discuss two interconnected threshold hypotheses: (1) in countries where law and order is strong enough, democratization stimulates economic growth, whereas in countries with poor law and order democratization undermines growth; (2) if democratization occurs under the conditions of poor law and order (so that illiberal democracy emerges), then shadow economy expands, quality of governance worsens, and macroeconomic policy becomes less prudent. We adduce a number of stylized facts to support our hypotheses. However our econometric findings are mixed: we report results that support the hypotheses as well as regressions that contradict them

StreetSmart Traffic: Discovering and Disseminating Automobile Congestion Using VANET's

utomobile traffic is a major problem in developed societies. We collectively waste huge amounts of time and resources traveling through traffic congestion. Drivers choose the route that they believe will be the fastest; however traffic congestion can significantly change the duration of a trip. Significant savings of fuel and time could be achieved if traffic congestion patterns could be effectively discovered and disseminated to drivers. We propose a system that uses a standard GPS driving aid, augmented with peer-to-peer wireless communication. The proposed system uses a combination of clustering and epidemic communication to find and disseminate dynamic traffic patterns

Asset Price And Current Account Dynamics

We examine the interaction between asset market and current account in a small open economy. In an overlapping generations economy in which land and money are available assets, the interaction between the land price and current account dynamics is shown to generate a plausible (asset price) specie-flow mechanism. We apply them to a number of issues. Domestic credit policy is neutral in the long run: one unit of foreign reserve increase offsets one unit of credit reduction. Next, the association between the endowment of land and foreign asset accumulation depends on parameters of the model. Finally, we examine the dynamic adjustment s following a once-and-for-all capital inflow. When the adjustment involves running current account deficit, the recipient country's foreign reserve position is permanently lowered. Furthermore, the steady state level of national wealth is permanently reduced. [E4, F3]