Histogram matching for the calibration of kNN stem volume estimates

The k-nearest neighbours (kNN) methods have been used successfully in many countries for the production of spatially comprehensive raster databases of forest attributes, made from the combination of National Forest Inventory (NFI) and satellite data. In Sweden, country-wide kNN estimates of forest variables have been produced to represent the forest condition in the years 2000 and 2005 by using a combination of Système Pour l'Observation de la Terre 5 (SPOT 5) satellite data and field data from the Swedish NFI. The resulting products are wall-to-wall raster maps with estimates of total stem volume, stem volume per tree species, tree height and stand age and a 25?×?25 m² pixel resolution. However, probability-based kNN stem volume estimates tend to have a suppressed variation range as large values are usually underestimated and small values are overestimated. One way to handle this problem is to calibrate the kNN stem volume estimates to the reference distribution of stem volume observations by histogram matching (HM) for a defined geographic area.

In this study, we have tested HM for the calibration of kNN total stem volume raster maps to the reference distribution captured by a forest inventory (FI) from 106 stands in Strömsjöliden, in the north of Sweden. The available field FI data set comprises 1084 circular plots, divided into a reference data set and an evaluation data set of total stem volume observations. The reference data set was used for the creation of a cumulative frequency histogram of total stem volume and the evaluation data set was used to assess the accuracy of volume estimates, before and after HM. The HM adjusted the cumulative distribution of the kNN data set to the distribution of the reference observations and resulted in a distribution of kNN estimates of total stem volume, which corresponded closely to that of the evaluation data set. The results show that the variation range of the kNN stem volume estimates can be extended by HM both on the pixel and stand levels. The extension of the range of estimates towards the range provided by the field observations allows improvement of kNN volume estimation for use in forest management planning based on stand-level analysis, given that the reference stem volume distribution can be estimated accurately, for example, using field data from NFI.     

Entity Notation: enabling knowledge representations for resource-constrained sensors

The forthcoming ambient systems will contain a large amount of sensors. Representing the data produced by these sensors in a format suitable for ambient intelligence applications would enable a large number of useful services. However, such formats tend to require processing power and communication bandwidth not available in many sensors utilizing ultra low-power microcontrollers and radio chip solutions. This paper presents a lightweight data representation, Entity Notation, to tackle this problem. Sensors with limited computation and communication capabilities can use Entity Notation to describe the data they produce. Entity Notation can be transformed into knowledge representations in a straightforward manner, and hence, the data produced by sensor nodes can be utilized with ease by any ambient intelligence system compatible with the common knowledge representations. This paper presents the design of Entity Notation, its implementations on embedded sensors and the evaluation of its performance.     

The modification of lactic acid based poly(ester-urethane) by copolymerization

Copolymers of L-lactic acid (LLA) with DL-mandelic acid (DLMA), 4-hydroxybenzoic acid, 4-acetoxybenzoic acid, DL-malic acid, or anhydrous citric acid were synthesized via direct copolycondensation in the presence of 1,4-butanediol, using stannous octoate as catalyst. The effect of the comonomer and the comonomer ratio on polycondensation and the glass transition temperature were investigated. The glass transition temperature of amorphous poly(L-lactic acid-co-DL-mandelic acid) increased linearly from 33° to 56°C as the mandelic acid composition was increased from 0 to 45 mol %. For urethane synthesis, prepolymers of LLA and DLMA were condensation polymerized with compositions of 100/0, 90/10, and 80/20 (mol % in feed). The preparation of poly(ester-urethane) (PEU) was carried out in a stirred glass reactor, using 1,6-hexamethylene diisocyanate and isophorone diisocyanate in melt. The glass transition temperature of poly(L-lactic acid-co-DL-mandelic acid-urethanes) showed a marked increase with increased mandelic acid composition. The molecular weights of these urethanes were lower than for PEU based on poly(L-lactic acid). Such a depression in the degree of polymerization is attributed to the steric hindrance of the bulky phenyl group as a side chain of mandelic acid. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1865–1872, 1997     

Prevalence and genetic diversity of Listeria monocytogenes in the tonsils of pigs

This study was set up to establish the prevalence of Listeria monocytogenes in the tonsils of sows and fattening pigs from five Finnish slaughterhouses and to evaluate the genetic similarity of L. monocytogenes strains isolated from the tonsils. A total of 271 pig tonsils (132 tonsils from fattening pigs and 139 from sows) from five different slaughterhouses in various parts of Finland were studied from June 1999 to March 2000. Overall, 14 and 4% of pig tonsils harbored L. monocytogenes and Listeria innocua, respectively. The prevalence of L. monocytogenes in tonsils of fattening pigs (22%) was significantly higher than in sows (6%). The isolates (n = 38) recovered from tonsils showed a wide genetic diversity by means of 24 different pulsed-field gel electrophoresis (PFGE) types presented by the strains. Moreover, in numerical analyses of restriction patterns, no association was found between the clustering of strains and the slaughterhouses, and strains showing a similar PFGE type were recovered from pigs of different slaughterhouses. The high prevalence of L. monocytogenes showing various PFGE types in the tonsils of pigs could indicate a potential source of contamination of pluck sets, carcasses, and the slaughterhouse environment and of subsequent processing steps.     

Raw and processed fish show identical Listeria monocytogenes genotypes with pulsed-field gel electrophoresis

A total of 257 raw fish samples at two different sites were examined for the presence of Listeria monocytogenes. The prevalence of L. monocytogenes was 4%. From 11 positive samples, nine different L. monocytogenes pulsed-field gel electrophoresis genotypes were recovered. From nine pulsotypes recovered from raw fish and 32 pulsotypes shown by 101 fish product isolates, two raw fish and fish product pulsotypes were indistinguishable from each other. Although the prevalence of L. monocytogenes in raw fish is low, the range of L. monocytogenes strains entering the processing plant in large amounts of raw material is wide. This indicates that the raw material is an important initial contamination source of L. monocytogenes in fish processing plants. This postulation is supported by the identical pulsotypes recovered from both raw and processed fish. Some L. monocytogenes strains entering a plant may thus contaminate and persist in the processing environment, causing recurrent contamination of the final products via processing machines.     

Electrodialytic removal of cadmium from wastewater sludge

This paper presents for the first time laboratory results demonstrating electrodialytic removal of Cd from wastewater sludge, which is a method originally developed for soil remediation. During the remediation a stirred suspension of wastewater sludge was exposed to an electric dc field. The liquid/solid (ml/g fresh sludge) ratio was between 1.4 and 2. Three experiments were performed where the sludge was suspended in distilled water, citric acid or HNO3. The experimental conditions were otherwise identical. The Cd removal in the three experiments was 69, 70 and 67%, respectively, thus the removal was approximately the same. Chemical extraction experiments with acidic solutions showed that 5-10 times more Cd could be extracted from decomposed sludge than from fresh sludge. It is likely that the mobilization of Cd during decomposition of the sludge contributes to the efficient removal of Cd by the electrodialytic method. Extraction experiments and electrodialytic remediation using distilled water as enhancement agent showed that 0.3% Cd could be extracted from decomposed sludge during 1 week in closed flasks, whereas 69% was removed during 2 weeks of electrodialytic remediation in a stirred solution in contact with atmospheric air. A combination of aerobic decomposition and electrodialytic treatment could be a promising method for Cd removal from wastewater sludge, and thus Cd could be removed without the addition of chemicals to the sludge.     

Signaled Step Size for Downlink Power Control of Dedicated Channels in UTRA TDD

This paper discusses downlink inner loop power control of dedicated channels in UTRA TDD. The current UTRA TDD downlink power control is similar to one in UTRA FDD mode, that comprises of closed inner loop and quality based outer loop. However, due to the time division feature and associated fexibility with asymmetry of TDD, the inner loop can not react as fast as in FDD and it is affected by rapid changes in environment. Therefore, the effect of the inner loop algorithm to the performance of UTRA TDD network is studied in this paper. Especially, the use of asymmetric step sizes for power up and power down commands is evaluated in contrast to the conventional symmetric power adjustment. Since it would be beneficial for the downlink inner loop power control to reach the target SIR as fast as possible, the power control step size based on the difference between the UE measured SIR and target SIR would be the most desirable power adjustment. Since the effectiveness of this type of an algorithm depends on available signaling bandwidth that is used, a study is carried out to find the tradeoff between the signaling bandwidth and related network performance.Janne Kurjenniemi was born in Jyväskylä, Finland, in March 1974. He received the M.Sc. in telecommunications in 2001 from the University of Jyväskylä, Jyväskyl, Finland. He is working as a Researcher at the Department of Mathematical Information Technology, University of Jyväskylä. His research interests include radio resource management for wireless communication systems.Otto-Aleksanteri Lehtinen was born in Tampere, Finland, in September 1971. He received the Master of Science in Technology in 1999 from the Helsinki University of Technology, Department of Electrical engineering (major in radio technology, minor signal processing and computer devices). His research interests include radio resource management for wireless communication systems.Tapani Ristaniemi was born in Kauhava, Finland, in 1971. He received the M.Sc. in mathematics in 1995, Ph.Lic. in applied mathematics in 1997, and Ph.D. in telecommunications in 2000 from the University of Jyväskylä, Jyväskylä, Finland. During 2001–2003 he was a professor of telecommunications at the Department of Mathematical Information Technology, University of Jyväskylä. In 2003 he joined the Institute of Communications Engineering in the Tampere University of Technology, Finland, where he has been a professor of wireless data communications. His research interests include signal processing for communications and radio resource management for wireless networks.     

Supporting visually impaired children with software agents in a multimodal learning environment

Visually impaired children have a great disadvantage in the modern society since their ability to use modern computer technology is limited due to inappropriate user interfaces. The aim of the work presented in this paper was to develop a multimodal software architecture and applications to support learning of visually impaired children. The software architecture is based on software agents, and has specific support for visual, auditory and haptic interaction. It has been used successfully with different groups of 7-8 year-old and 12 year-old visually impaired children. In this paper we discuss the enabling software technology and interaction techniques aimed to realize our goal and our experiences in the actual use of the system.     

Coupling Element-Based Dual-Antenna Structures for Mobile Terminal with Hand Effects

This paper presents a comprehensive simulation study on the performance of coupling element-based dual-antenna structures on a mobile terminal at the 2,000 MHz Universal Mobile Telecommunications System (UMTS) frequency band with varying two significant hand effects; vertical position of hand along terminal chassis, and distance between hand palm and terminal chassis. The results reveal that in uniformly distributed isotropic environment, there exists a gain imbalance between antenna elements due to hand effects and it is shown that a gain imbalance of 3.7 dB lead to a reduction of 1.9 dB in diversity gain at 99% reliability level using maximal ratio combining (MRC) technique. For a dual-antenna configuration, the impact of gain imbalance on diversity gain is more significant when only one antenna element is in close proximity to the hand, compared to when both antenna elements are in the presence of the hand. It is also shown that a dual-antenna structure with elements vertically oriented along the edges of a small 100 mm × 40 mm mobile terminal chassis achieves better performance in port-to-port isolation, gain imbalance and diversity gain compared to other studied dual-antenna configurations when the user’s hand is present.