As Unmanned Aircraft Systems (UAS) become more accepted into our society, law enforcement, emergency services, and commercial entities will begin taking advantage of this technology in high-population urban settings. Since these aircraft will be operating between and above the high-rise buildings that de ne most urban cores, increased position estimation accuracy will become paramount to ensure...

The Reynolds-averaged Navier-Stokes (RANS) model and revised generalized drift flux model were used to investigate the characteristics of airflow fields and PM2.5 dispersion in street canyons with a variety setting on tree crown morphologies (i.e., conical, spherical, and cylindrical), leaf area densities (LADs = 0.5, 1.5, and 2.5 m2/m3), and street canyon aspect ratios (H/W = 0.5, 1.0, and 2.0...

A new GPS positioning algorithm for vehicle tracking namely the “Minimum Range Error Algorithm” (MRERA) was proposed by E. Mok and L. Lam, to track vehicles in dense high-rise environments without the use of dead reckoning, and it can also be used for general geolocation positioning applications. With this algorithm, it is possible to identify which section of road network the mobile user is lo...

Horseshoe waterfalls are ubiquitous in natural streams, bedrock canyons, and engineering structures. Nevertheless, water flow patterns upstream of horseshoe waterfalls are poorly known and likely differ from the better studied case of a one-dimensional linear step because of flow focusing into the horseshoe. This is a significant knowledge gap because the hydraulics at waterfalls controls sedim...

Abstract Accurate positioning in urban canyons remains a challenging problem. To facilitate the research and development of reliable precise methods using multiple sensors canyons, we built multisensory dataset, UrbanNav, collected diverse, scenarios Hong Kong. The dataset provides multi-sensor data, including data from multi-frequency global navigation satellite system (GNSS) r...

Abstract. Trees provide many ecosystem services in cities such as urban heat island reduction, water runoff limitation, and carbon storage. However, the presence of trees street canyons reduces wind velocity limits pollutant dispersion. Thus, to obtain accurate simulations concentrations, aerodynamic effect should be taken into account air quality models at level. The Model Urban Network Inters...

Urban montane valleys are often characterized by periodic wintertime temperature inversions (cold air pools) that increase atmospheric particulate matter concentrations, potentially stimulating the deposition of major ions to these snow-covered ecosystems. We assessed spatial and temporal patterns of ion concentrations in snow across urban to montane gradients in Salt Lake City, Utah, USA, and ...