Location Estimation via Support Vector Regression

Location estimation using the global system for mobile communication (GSM) is an emerging application that infers the location of the mobile receiver from multiple signals measurements. While geometrical and signal propagation models have been deployed to tackle this estimation problem, the terrain factors and power fluctuations have confined the accuracy of such estimation. Using support vector regression, we investigate the missing value location estimation problem by providing theoretical and empirical analysis on existing and novel kernels. A novel synthetic experiment is designed to compare the performances of different location estimation approaches. The proposed support vector regression approach shows promising performances, especially in terrains with local variations in environmental factors     

Bestimmung des Endotoxin-Gehalts in Eiprodukten mit Hilfe eines miniaturisierten chromogenen Limulus-Tests

Zusammenfassung Die Eignung eines chromogenenLimulus-Tests zur Bestimmung des Endotoxin-Gehalts in Eiprodukten wurde gepruft. Dabei zeigte die Analyse verschieden stark bakteriell belasteter Volleimassen eine deutliche Korrelation zwischen Endotoxin-Konzentration und Gesamtkeimzahl (6 x 10⁴ cfu x ng^–1 Endotoxin) Bowie der Anzahl vonEnterobacteriaceen (7x10² cfu x ng^–1 Endotoxin). Vergleichbare Ergebnisse konnten auch mit Eigelb- und Eiweilßproben erzielt werden. Der Endotoxin-Nachweis wurde durch Hitzebehandlung (65 °C, 60 min) nicht beeinflußt. Endotoxinfreies steriles Volleimaterial hatte bis zu einer Konzentration im Testansatz von 10 mg x ml^–1 keinen Einfluß auf das Mcßergebnis. Im vorliegenden Bericht wird eine miniaturisierte Version des Testverfahrens vorgestellt, die im Mikro titerplatten-System durchgeführt werden kann.

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Determination of endotoxin in egg products with a miniaturized chromogenic Limulus test

Summary A chromogenicLimulus amoebocyte lysate assay was applied to monitor endotoxin concentration in egg products. Analysis of differently contaminated whole egg probes revealed a strong correlation of endotoxin concentration to total bacterial count 6 x 10⁴ cfu x ng^–1, where cfu=colony-forming unit) as well as to number ofEnterobacteriaceae (1 ng/7 x 10² cfu). Similar relations were also found for egg white and egg yolk probes. A significant influence of heat pretreatment of egg probes (65° C, 60 min) on endotoxin detection could be excluded. Up to a concentration of 10 mg x µl^–1 endotoxin-free whole egg material did not interfere with the test system. A miniaturized version of the chromogenicLimulus test, which can be carried out in microtiter plates, is described.

     

Nachweis von Maillard-Produkten in Malzen, Bieren und Braucouleuren

Zusammenfassung Bei der Maillard-Reaktion reagieren primär reduzierende Zucker mit den freien Aminogruppen der Aminosäuren. Dabei entstehen aus Aldosen als erste stabile Zwischenprodukte die 1-Aminosäure-1-desoxy-ketosen (Amadori-Verbindungen). In Malzen konnten zehn Amadori-Verbindungen quantitativ bestimmt werden. Sie entstehen während des Darrens des Malzes. Aufgrund unterschiedlicher Darrbedingungen unterscheiden sich die Malztypen im Gehalt und im Muster dieser Substanzen. Während der Erhitzungsvorgänge beim Brauprozeß (Maischen, Würzekochung) werden die Amadori-Verbindungen etwa zur Hälfte abgebaut, dagegen sind bei der an schließenden Gärung keine Veränderungen zu beobachten. Aus dem Gehalt und dem Muster der Amadori-Verbindungen im Bier können somit Rückschlüsse auf das verwendete Malz gezogen werden. Bei der Herstellung von Braucouleuren werden Ammoniak bzw. Ammoniumverbindungen als Aminokomponenten eingesetzt. Die Couleure enthalten deshalb keine 1-Aminosäure-l-desoxy-ketosen, dafür aber Desoxyfructosazine, die bei der Reaktion von Zuckern mit Ammoniak entstehen. Diese Pyrazinderivate wurden in Braucouleuren in hohen Mengen (2–6 g/100 g) gefunden. Es wird eine Methode vorgestellt, mit der ein Zusatz von Braucouleuren zum Bier über die Bestimmung der Desoxyfructosazine eindeutig nachgewiesen werden kann.

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Detection of Maillard products in malts, beers, and brewing couleurs

During the Maillard reaction, the reducing sugars first react with the free amino groups of the amino acids. With aldoses, 1-amino-l-deoxyketoses (ketose-amino acids, Amadori compounds) are the first stable intermediates to be formed. In malts ten different Amadori compounds could be determined that formed during the kiln-drying of malt. Dependent on the kiln-drying conditions, the different types of malt contain different amounts and proportions of these compounds. During the brewing process (mashing, mash wort cooking) about half of the Amadori compounds are decomposed, whereas during fermentation no changes can be observed. Therefore the amount and composition of Amadori compounds detected in beer may indicate the type of malt used. During the production of brewing couleurs, ammonia or ammonium compounds react with sugars and deoxyfructosazines are formed. In brewing coleurs, relatively high amount of these pyrazine derivatives (2–6 g/100 g) could be found. An analytical method is described for the quantitative determination of deoxyfructosazines, indicating an addition of brewing couleur to beer.

     

Parallel Adder Design with Reduced Circuit Complexity Using Resonant Tunneling Transistors and Threshold Logic

Quantum-effect devices utilizing resonant tunneling are promising candidates for future nano-scale integration. Originating from the technological progress of semiconductor technology, circuit architectures with reduced complexity are investigated by exploiting the negative-differential resistance of resonant tunneling devices. In this paper a resonant tunneling device threshold logic family based on the Monostable-Bistable Transition Logic Element (MOBILE) is proposed and applied to different parallel adder designs, such as ripple carry and binary carry lookahead adders. The basic device is a resonant tunneling transistor (RTT) composed of a resonant tunneling diode monolithically integrated on the drain contact layer of a heterostructure field effect transistor. On the circuit level the key components are a programmable NAND/NOR logic gate, threshold logic gates, and parallel counters. The special properties of MOBILE logic gates are considered by a bit-level pipelined circuit style. Experimental results are presented for the NAND/NOR logic gate.     

Effects of fade distribution on a mobile satellite down-link and up-link performance in a frequency reuse cellular configuration

In a mobile satellite system with a frequency reuse cellular configuration, significant co-channel interference can be experienced due to the antenna side-lobe level. The signal will be subjected not only to its own fading, but also to the effect of the varying degree of fading on the co-channel interferer, and this interference will behave differently in the up and in the down-link. This paper presents a quantitative evaluation of the combined effects of fades and co-channel interference on a mobile satellite link.     

Estimation of dynamically evolving ellipsoids with applications to medical imaging

The estimation of dynamically evolving ellipsoids from noisy lower-dimensional projections is examined. In particular, this work describes a model-based approach using geometric reconstruction and recursive estimation techniques to obtain a dynamic estimate of left-ventricular ejection fraction from a gated set of planar myocardial perfusion images. The proposed approach differs from current ejection fraction estimation techniques both in the imaging modality used and in the subsequent processing which yields a dynamic ejection fraction estimate. For this work, the left ventricle is modeled as a dynamically evolving three-dimensional (3-D) ellipsoid. The left-ventricular outline observed in the myocardial perfusion images is then modeled as a dynamic, two-dimensional (2-D) ellipsoid, obtained as the projection of the former 3-D ellipsoid. This data is processed in two ways: first, as a 3-D dynamic ellipsoid reconstruction problem; second, each view is considered as a 2-D dynamic ellipse estimation problem and then the 3-D ejection fraction is obtained by combining the effective 2-D ejection fractions of each view. The approximating ellipsoids are reconstructed using a Rauch-Tung-Striebel smoothing filter, which produces an ejection fraction estimate that is more robust to noise since it is based on the entire data set; in contrast, traditional ejection fraction estimates are based only on true frames of data. Further, numerical studies of the sensitivity of this approach to unknown dynamics and projection geometry are presented, providing a rational basis for specifying system parameters. This investigation includes estimation of ejection fraction from both simulated and real data.     

Contact Doping for Vertical Organic Field‐Effect Transistors

Doping is a powerful tool to overcome contact limitations in short‐channel organic field‐effect transistors (OFETs) and has been successfully used in the past to improve the charge carrier injection in OFETs. The present study applies this familiar concept to the architecture of vertical organic field‐effect transistors (VOFETs), which are often severely limited by injection due to their very short channel lengths. The present study shows that the performance of p‐type VOFETs with pentacene as an active material can be significantly enhanced by the addition of the common p‐dopant C₆₀F₃₆ as a thin injection layer underneath the VOFET source electrode, resulting in an increase of On‐state current and On/Off ratio by one order of magnitude. The present study further investigates mixed injection layers of pentacene and the p‐dopant and finds that the improvement is less pronounced than for the pure dopant layers and depends on the concentration of dopant molecules in the injection layer. Through application of the transfer length method to equivalent OFET geometries, the present study is finally able to link the observed improvement to a decrease in transfer length and can thus conclude that this length is a crucial parameter onto which further improvement efforts have to be concentrated to realize true short‐channel VOFETs.     

Chloride and Indium‐Chloride‐Complex Inorganic Ligands for Efficient Stabilization of Nanocrystals in Solution and Doping of Nanocrystal Solids

Here, the surface functionalization of CdSe and CdSe/CdS core/shell nanocrystals (NCs) with compact chloride and indium‐chloride‐complex ligands is reported. The ligands provide not only short interparticle distances but additionally control doping and passivation of surface trap states, leading to enhanced electronic coupling in NC‐based arrays. The solids based on these NCs show an excellent electronic transport behavior after heat treatment at the relatively low temperature of 190 °C. Indeed, the indium‐chlorido‐capped 4.5 nm CdSe NC based thin‐film field‐effect transistor reaches a saturation mobility of μ = 4.1 cm² (V s)^?1 accompanied by a low hysteresis, while retaining the typical features of strongly quantum confined semiconductor NCs. The capping with chloride ions preserves the high photoluminescence quantum yield ( ≈ 66%) of CdSe/CdS core/shell NCs even when the CdS shell is relatively thin (six monolayers). The simplicity of the chemical incorporation of chlorine and indium species via solution ligand exchange, the efficient electronic passivation of the NC surface, as well as their high stability as dispersions make these materials especially attractive for wide‐area solution‐processable fabrication of NC‐based devices.