Predicting the spatial pattern of trees by airborne laser scanning

The spatial pattern of trees can be defined as a property of their location in relation to each other. In this study, the spatial pattern was summarized into three categories, regular, random, and clustered, using Ripley's L-function. The study was carried out at 79 sample plots located in a managed forest in Finland. The goal was to study how well the spatial pattern of trees can be predicted by airborne laser scanning (ALS) data. ALS-derived predictions were based upon individual tree detection (ITD), semi-individual tree detection (semi-ITD), and plot-level metrics calculated from the canopy height model, AREA. The kappa value for ITD was almost zero, which indicates no agreement. The semi-ITD and AREA methods performed better, although kappa values were only 0.34 and 0.24, respectively. It appears difficult to detect a particularly clustered spatial pattern.     

Assembling approximately optimal binary search trees efficiently using arithmetics

We introduce a new algorithm for computing an approximately optimal binary search tree with known access probabilities or weights on items. The algorithm is simple to implement and it has two contributions. First, a randomized variant of the algorithm produces a binary search tree with expected performance that improves the previous theoretical guarantees (the performance is dependent on the value of the input random variable). More precisely, if p is the probability of accessing an item, then under expectation the item is found after searching lg1/p+0.087+lg₂(1+pmax) nodes, where pmax is the maximal probability among items. The previous best bound was lg1/p+1, albeit deterministic. For the optimal tree our upper bound implies a non-constructive performance bound of H+0.087+lg₂(1+pmax), where H is the entropy on the item distribution and the previous bound was H+1. The second contribution of the algorithm is a low cost in i/o models of cost such as the cache-oblivious model, while attaining simultaneously the above bound for the produced tree.     

The role of utility models in patent filing strategies: evidence from European countries

We examine the role of utility models (UM) in patent filing strategies. With an extensive patent family data from European countries, we explore the structures and characteristics of patent families, which include UMs. A simple typology of patent families with UM members is introduced. We document that the geographical scope of most patent families with UM members is purely national, which is in line with the conventional view that the UM mechanism covers technologically and economically marginal inventions. However, the image of a UM as a signal of a minor invention is an oversimplification. Applicants exhibit a mixture of uses for the UM and there exists a subset of UM filings linked to inventions the inventive step of which meets or exceeds the threshold required for patent protection. Some UMs are members of international patent families, indicating that applicants may have some strategic motives to use UMs in international filing. The findings highlight that both types of IPR documents (UMs and patents) should be taken into account when working with data on patent families, analyzing patent filing strategies, and constructing patent-based indicators such as patenting propensities.     

Recovering gold from copper concentrate via the HydroCopper™ process

HydroCopper? technology comprises a chloride-leaching method for copper sulfide concentrates and copper production up to semi-products. As compared with the commonly used sulfate solutions, brine solutions offer aggressiveness and stability of the copper(I) ion and, consequently, a lower energy consumption in leaching. Copper(II) ions and oxygen are used as oxidants. Iron reports to the leaching residue as oxide and sulfur as elemental sulfur. Gold is dissolved and recovered in the third stage of the counter-current leaching when the redox potential reaches higher levels.     

Quantization noise upconversion effects in mixer-first direct delta-sigma receivers

In this paper, we investigate the application of the direct ΔΣ receiver (DDSR) concept in a mixer-first architecture. Specifically, we analyze the degrading effects of quantization noise (Q_n) upconversion on DDSR sensitivity, which is a major concern in mixer-first DDSR architecture. We demonstrate that with the chosen approach, the mixer-first architecture is suitable for the DDSR despite the potential challenges arising from Q_n upconversion. A systematic modeling and understanding of Q_n upconversion effects is presented, which lead to simple design guidelines. The results demonstrate that a first-order low-pass Q_n filtering is sufficient in most cases for mixer-first DDSR implementations. Based on analytical results, we design a transistor-level mixer-first DDSR by merging the functionality of N-path capacitors both as channel select and Q_n filters. Simulations performed in a 28-nm complementary metal-oxideŰsemiconductor (CMOS) process show a mere 1.5-dB degradation from maximum signal-to-noise and distortion ratio (SNDR) for the worst-case scenarios arising from Q_n upconversion effects, validating the chosen approach.     

Comparison of color vision models based on spectral color representation

Recent break‐throughs in retinal imaging have raised new questions for color vision research, and the existing color vision models should be re‐evaluated. Many color vision models are based on an assumption that there are no differences in the detection phase, neither in the spatial configuration nor in the spectral sensitivities of cells. In this article, we have run experiments with four different color vision models. This evaluation gives us more knowledge about the essential properties of the models. We show how the tested color vision models are able to replicate the behaviour of human color vision by evaluating their performance in Farnsworth‐Munsell 100‐Hue color vision test. Also, the wavelength discrimination power of each model is presented and the properties of color spaces spanned by models are examined using samples from Munsell Book of Color. Our experiments show that there are large differences in the properties of different models. © 2009 Wiley Periodicals, Inc. Col Res Appl, 34, 341–350, 2009     

SiGe LNAs for UMTS System

Three LNAs at 2 GHz frequency range have been implemented in a SiGe Bipolar process targeted for a universal mobile telecommunications system. The LNAs are operating in two gain modes and they include a power-down mode. Both on-wafer and packaged LNAs were measured. Noise figure below 2 dB with IIP3 of 1 dBm and gain exceeding 15 dB has been achieved. LNAs work from a 2.7–5.5 V power supply. A figure of merit method is used to compare this work to other published LNAs.     

Energy-efficient control strategy for variable speed-driven parallel pumping systems

The article aims to find a solution for the energy efficiency improvements in variable speed-controlled parallel pumping systems with lesser initial data and without additional flow metering and start-up measurements. This paper introduces a new control strategy for variable speed-controlled parallel pumps based on flow rate estimation and pump operation analysis utilizing variable speed drives. The energy-saving potential of the new control strategy is studied with simulations and laboratory measurements. The energy consumption of the parallel pumps using the new control strategy is compared with the traditional rotational speed control strategy of parallel pumps. The benefit of the new control strategy is the opportunity to operate variable speed-controlled parallel pumps in a region which suggests improved energy efficiency and lower risk of mechanical failure of the controlled pumps compared with traditional control. The article concludes by discussing the implications of the findings for different applications and varying system conditions.     

Increasing trends of total organic carbon concentrations in small forest lakes in Finland from 1987 to 2003

Trends in total organic carbon (TOC) concentrations over the period 1987-2003 were studied in 13 small forest lakes. Recovery from acidification (reduced SO(4) deposition) and long-term changes in runoff as potential drivers for the trends were examined. The results showed that TOC concentrations have increased throughout Finland. Ten of the 13 lakes showed a significant increasing TOC trend (p<0.05), and included both clear water and humic lakes. The largest annual increase in TOC occurred in lakes with the largest average concentrations. The magnitude of the TOC trends were not significantly related to the proportion of peat soils in the catchment but the catchment size was an important predictor. Decreasing SO(4) deposition and improved acid-base status in soil due to the recovery from acidification implied an increased mobilisation of organic acids and TOC. There was little evidence that the long-term increasing trend in TOC concentrations was related to long-term changes in runoff. However, large seasonal and inter-annual fluctuations in runoff did appear to affect TOC concentrations for a number of years.     

Relationship between perceived problem‐solving skills and academic performance of novice learners in introductory programming courses

Past research has shown that student problem‐solving skills may be used to determine student final exam performance. This study reports on the relationship between student perceived problem‐solving skills 1 1 Henceforth, for brevity, we drop the word “perceived” in “student perceived problem‐solving skills” and use either “student perceived problem solving” or simply “student PSS.”
and academic performance in introductory programming, in formative and summative programming assessment tasks. We found that the more effective problem solvers achieved better final exam scores. There was no significant difference in formative assessment performances between effective and poor problem solvers. It is also possible to categorize students on the basis of problem‐solving skills, in order to exploit opportunities to improve learning around constructivist learning theory. Finally, our study identified transferability skills and the study may be extended to identify the impact of problem solving transfer skills on student problem solving for programming.