bluuebunny/crossref_metadata_2025 huggingface dataset:
Recognition of Optical Microscopy Images Based on Shape and Texture
Authors: Zhang Shu Heng , Yang Wei , Wang Lian Yun , Zhang Su
Published: September 2012

Airborne pollen is the main cause of pollen allergy, so statistic of the amount and distribution of pollen in the air is important. This paper presents a method to identify airborne pollen grains in optical microscopy images. After pollen region is segmented by thresholding, global shape descriptor and Fourier descriptor are used to extract shape features, gray level co-occurrence matrix is employed to extract texture features, and finally pollen grains are classified by a k-nearest neighborhood classifier. In the experiment with 55 cases ofPoaceae, 44 cases ofMoraceaeand 48 cases ofPinaceae, a classification rate of 82.31% can be obtained with an accuracy of 85.45%, 61.36%, and 97.91% for each family.
High-Accuracy Carrier Frequency Offset Estimation for MPSK Signals
Authors: Zhang Dong Ling , Ge Lin Dong
Published: September 2012

In this paper a high accuracy estimation algorithm of carrier frequency offset for MPSK signals in Gaussian white noise is proposed. Like the conventional practice, first the algorithm employs nonlinear processing to convert the MPSK signal to single sinusoidal signal, followed by windowed FFT, and then a method based on energy center correction is used to achieve accurate estimation. Simulation results have proved the feasibility,easiness of implementation, and the performance improvements in terms of accuracy and data length needed.
Numerical Simulation of Water Transport through Vessel Perforation Plates
Authors: Chen Qi , Xu Fang , Ai Qin Lin , Chen Jiao Liao
Published: September 2012

The structure of perforation plate had a substantial effect on the water conductivity of plant vessels. As the microscopic structure of vessel and perforation plate is highly complex, it is very difficult to numerically solve the flow equations. The effects of perforation plate structure on water flow in plant xylem vessels were studied using CFD (computational fluid dynamics) approach, the calculation results were used to estimate the effects of the perforation plate on conductance. Results showed that simple plate provided less resistance than scalariform plate. The resistance to flow through the perforation plate increased as the plate angle increased (giving same number of pores). Increasing the pore size would reduce the resistance along the modeled vessel. The results also showed that gravity had hardly effect on flow characteristics in micro vessels of plant and nearly can be neglected.
Simulation of a Single-Radio Multi-Channel Vehicular Node Structure for VANET in NS-2
Authors: Wang Jie , Wang Xin Hong , Zhang Guo Xia , Liu Fu Qiang
Published: September 2012

We propose a universal single-radio multi-channel vehicle node structure (VNS) in NS-2 for VANET simulation. VNS can support different single-radio multi-channel MAC protocols, while in this paper we implement a split-phase mode MAC as channel coordination mechanism, with a three-way handshake as channel negotiation mechanism. Simulation results in sparse, dense and moving scenarios indicate that VNS is a preferable solution for simulation of VANET.
Dynamic Characteristics Simulation for Lifting Mechanism of Dump Truck Based on Virtual Prototype
Authors: Jiang Rong Chao , Liu Da Wei , Wang Zhong Chang , Fan Wei
Published: September 2012

In order to study the dynamic characteristics of dump truck with a T-type lifting mechanism, a detailed multi-body dynamic model of a dump truck was established by using SIMPACK software. With this model, which includes front suspension, balanced rear suspension, carriage, lifting mechanism, tyre model and so on, the kinematics and dynamics of the dump truck were studied by simulation. The variation of angular velocity, angular acceleration and applied force of carriage, tension rod and cylinder with lifting angle were obtained. This study will provide scientific reference for the structural design and strength analysis of lifting mechanism.
An Application of System Dynamic Approach to Urban Sustainable Development Evaluation
Authors: Shang Hai Yang , Su Fang
Published: September 2012

Evaluation for urban sustainable development is very significant to improve the future development of urban. The analytic hierarchy process (AHP) is very popular used to evaluate the urban sustainable development, but limited to forecasting the future development. In the study, a model designed based on SD and AHP is expected to resolve this problem. And we take Zhangye city in Gansu province as an example to study the evaluation performance of the model. The result of the urban sustainable development is getting better and better towards 2020. The result shows that the development of Zhangye city is going to be good in future 10 years. The experimental results indicate the effectiveness and correctness of the proposed method.
Fracture Mechanics Analysis of Functionally Graded Material Based on Finite Element Method
Authors: He Bo , Zhang Hong Cai
Published: September 2012

In this paper, the fracture problem of functionally graded material (FGM) was studied, and the shear modulus was assumed to be an exponential function. The influences of inhomogeneous parameter, crack size and crack angle on the stress intensity factors have been analyzed by the finite element method. The results indicated that the stress intensity factors of mode I decreased with the increasing of the crack angle, the stress intensity factors of mode II increased with the increasing of the crack angle, and the crack stress intensity factor of mode I and mode II decreased with the increasing of the inhomogeneous parameters at crack tips, which was of certain directive significance for the FGM design and manufacture in the actual engineering.
Study on Dynamic Characteristics of the Hippocampal Neuron under Current Conductance's Changing
Authors: Peng Yue Ping , Zou Nan , Wu Hai Ying
Published: September 2012

The hippocampal CA1 pyramid neuron has plenty of discharge actions. In the thesis, the dynamic characteristics of the hippocampal neuron model are analyzed and discussed by the neurodynamic theory and methods. Under a certain amplitude currents stimulation, the change of (the maximum conductance of the transient sodium channel) and (the maximum conductance of the delay rectification potassium channel) can cause different dynamic characteristics of the neuron model. The transient Na+current () caused by is indispensable in the discharges formation process of the model. The model can generate the discharge process only when reaches a certain threshold. In the discharge process of the neuron model,s changing affects little and the ISIs approximate to a straight line. The delay rectification K+current () caused by isnt indispensable in the discharges formation process of the model. Buts changing affects much in the discharge process of the neuron model. Withs changing, the neuron model undergoes different dynamic bifurcation process, and has plenty of discharge patterns such as the chaos, period, and so on. This investigation is helpful to know and investigate deeply the dynamic characteristics and the bifurcation mechanism of the hippocampal neuron; and it provides a certain theory assist to investigate the neural diseases such as the Alzheimer disease by neurodynamics.
Research on Control Algorithm for an Unmanned Helicopter Based on Global Asymptotic Stability
Authors: Guo Run Xia , Chen Jiu Sheng
Published: September 2012

Taking into account the different response speed of each part of the unmanned helicopter(UMH), established a two-timescale nonlinear model which contained the flapping and rotational dynamics. To overcome the problem that a number of terms cant be accounted in the state-dependent Riccati equation (SDRE) design, we employed a nonlinear feedforward compensator that is designed to match the vehicle response to the model used in the SDRE design. We improved SDRE technique and set up a control algorithm can guarantee the global asymptotic stability of the system. Proof was given. Numerical simulation results were listed to illustrate effectiveness of the algorithm.
The Deniability Analysis for a Deniable Authentication Protocol
Authors: Wei Da Wei , Liu Wei , Zhao Xiu Feng
Published: September 2012

The notion of deniable authentication is introduced by Dwork et al., deniable authentication protocols allow a sender to authenticate a message for receiver, in a way that the receiver cannot convince a third party that such authentication ever took place. Raimondo et al. present authentication protocol λProj and deniable version Den-λProj by adding challenge-response mechanism. In this paper we prove the protocol λProj without challenge-response is deniable against malicious verifier under subset witness assumption.
Structural Studies of Nanocrystalline Thin Pd Films Electrochemically Doped with Hydrogen
Authors: Čížek Jakub , Vlček Marián , Lukáč František , Vlach Martin , Procházka I. , Brauer Gerhard , Anwand Wolfgang , Mücklich A. , Wagner Stefan , Uchida Helmut , Pundt Astrid
Published: September 2012

Hydrogen absorption in Pd causes a significant volume expansion. In free-standing bulk Pd, the hydrogen-induced volume expansion is isotropic. However, the situation becomes more complicated in thin Pd films. Contrary to bulk samples, thin films are clamped to an elastically stiff substrate, which prevents in-plane expansion. Hence, the volume expansion of a thin film is strongly anisotropic because it expands in the out-of-plane direction only. Internal stresses introduced by absorbed hydrogen may become so high that detachment of a film from the substrate is energetically favorable and buckles of various morphologies are formed. In the present work, we studied hydrogen-induced buckling in a nanocrystalline thin Pd film deposited on a sapphire substrate. Slow positron implantation spectroscopy (SPIS) was employed as a principal tool for the characterization of defects and investigation of defect interactions with hydrogen. SPIS studies were combined with X-ray diffraction and direct observations of buckling by light microscopy. It was found that buckling of thin Pd film occurs at hydrogen concentrations xH > 0.1 and is accompanied by a strong increase of dislocation density.
Improvement of Barrier Soil Properties with Fly Ash to Minimize Desiccation Shrinkage
Authors: Amadi Agapitus A.
Published: September 2012

Barrier Systems Built with Fine Grained Soils Frequently Loose their Hydraulic Integrity due to Desiccation Cracking either during Construction or Shortly Thereafter. Moreover, Typical Specifications for the Construction of Compacted Soil Liners and Covers Require that the Soil Be Compacted Wet of Optimum Water Contents to Achieve the Lowest Possible Hydraulic Conductivity, a Condition that Results in High Desiccation Shrinkage Values. however, such Soils Can Be Treated with Fly Ash to Maintain Low and Tolerable Desiccation Shrinkage Strains. in this Study, Volumetric Shrinkage Strains of Representative Fine Grained Soil Containing 0 – 20% Fly Ash by Dry Weight of Soil Compacted with the British Standard Light (BSL), West African Standard (WAS) and British Standard Heavy, (BSH) Compaction Efforts at Moisture Contents Ranging from 10 – 20% Were Evaluated. Measurements Indicate that Volumetric Shrinkage Strain Decreased with Higher Fly Ash Content and that Fly Ash Effectively Reduced the Shrinkage of Untreated Soil Prepared Wet of Optimum from 4.4 – 7.7% to Values Well below the 4% Threshold. the Measured Shrinkage Strains Were Related to Water Content and Dry Unit Weight on the Dry Unit Weight – Moulding Water Content Curve in what Is Referred to as Acceptable Zone. Data Points within the Acceptable Zone Represent Test Results with Shrinkage Strain ≤ 4% which Ensures Compaction Efficiency. this Study Therefore Established that Fly Ash Application and Appropriate Regulation of the Moulding Water Content Are Feasible Means of Reducing the Risk of Barrier Soil Damage by Shrinkage Cracks while still Realizing Very Low Hydraulic Conductivity and Adequate Strength.
Managing Hardcopy Drawings
Authors: Tjiparuro Zeundjua , Situmbeko Shadreck Mumbiana
Published: September 2012

This Paper Presents a Classification System for Managing and Indexing Hardcopy Engineering Drawings, Referred to, in this Paper, as Drawings Library Management System (DLMS), Developed for an Appropriate Technology Research Centre in Botswana. the System Is Akin to Common Library Cataloguing and Classification Systems such as the Dewey Decimal Classification (DDC), Universal Decimal Classification and Others, which, though Are Well-Known and Have Been around for many Years, Are yet to Be Exploited for the Classification and Management of Paper Drawings. in Fact, Hardcopy Drawings Appear to Be Neglected Compared to the Softcopy Type, for which Various Scholarly Articles Have Been Done on their Classification, Retrieval and Management. this Is Unfortunate as, Invariably, it Is Hardcopy/paper Drawings that Are Mostly Used in Production, Especially in Developing Countries where the Power of CAD/CAM Is yet to Be Fully Harnessed. Accordingly, the DLMS, a Model Successfully Used in a Research Centre in Botswana for over Ten Years Is Proposed.The System Was Further Analysed against and Compared to Three Main Library Classification Systems, Namely, the Dewey Decimal, the Universal Decimal and the Library of Congress Systems. Results Show that the DLMS Is a Better Classification System for Managing Hardcopy Drawings.
Modified Trend and Seasonal Time Series Analysis for Operations: A Case Study of Soft Drink Production
Authors: Godwin Harold C. , Okafor C.E.
Published: September 2012

Many Production and Business Time Series Are Non-Stationary Time Series that Contain Trend and Seasonal Variations. Seasonality Is a Periodic and Recurrent Pattern Caused by Factors such as Weather, Holidays, or Repeating Promotions. this Paper Presents a Trend and Seasonal Time Series Analysis of Soft Drink Production over the Period 2003–2010, it Is Necessary to Know the Trend in Soft Drink Production to Elicit the Reasons why Demand of Soft Drink Is Increased or Decreased at Specific Periods. the Objectives of this Paper Are (i) to Study the Trends in the Production and Productivity of a Soft Drink Bottling Company, and (ii) Analyze the Demand of the Firm with a View to Identifying Trend that Exists in the Company Using Time Series Analysis. A Software Program Was Developed Based on Applicable Methodology to Facilitate Accurate and Faster Analysis of Data. Characterization of Demand Data Using Decomposition Was Done, which Reveal the Nature of Seasonality, Cyclical Activity, Trend and Noise. on the Whole, the Results of the Decomposition Analysis Clearly Show that there Is a Remarkable Linear Trend in Demand Pattern. the Study of Seasonality Shows that the Highest Peak in Demand of the Product Occurred at 12th, 24th, 36th, 48th 60th, 72nd, 84th and 96th Months which Turn Out to Coincide with Yuletide. the Study Further Indicated a Positively Increasing Trend in the Demand Rate of Company’s Product.
Variety of Bio-Hydrocarbon Precursors for the Synthesis of Carbon Nanotubes
Authors: Azmina M. S. , Suriani Abu Bakar , Salina M. , Azira A.A. , Dalila A.R. , Asli N.A. , Rosly J. , Nor Roslan Md. , Rusop M.
Published: September 2012

In this work, we have synthesized carbon nanotubes (CNT) using different bio-hydrocarbon precursors namely palm, olive, coconut, corn and sesame oils. Prior to the synthesis process, thermogravimetric analysis (TGA) characterization was performed on the carbon precursors to facilitate the optimization procedures of CNT and reach maximum yield and higher quality CNT. The CNT arrays were deposited on a silicon substrate by thermal catalytic decomposition of the precursor using 5.33 wt% ferrocene. The synthesis was carried out at 750 °C for 60 min under argon ambient. The samples were characterized using field emission scanning electron microscopy, micro-Raman spectroscopy and TGA analysis. The difference in oil density resulted in different quality and tube diameter of CNT produced. Among all, the CNT synthesized from coconut oil can be considered as the best bio-hydrocarbon precursor for higher quality (ID/IG ~0.62) and good purity (81.95 %) CNT.
Nanocomposites of Carbonated Hydroxyapatite/Poly (4-vinyl pyridine-co-styrene): Synthesis, Characterization and its Application
Authors: Dhanalakshmi C. P. , Vijayalakshmi L. , Narayanan V.
Published: September 2012

nanocarbonated hydroxyapatite/Poly (4-vinyl pyridine-co-styrene) composites of varying composition for biomaterial applications have been synthesized. The nanocarbonated hydroxyapatite/Poly (4-vinyl pyridine-co-styrene) composite materials were characterized by XRD, FTIR, 31P NMR, TGA, DTA and FESEM. Carbonated Hydroxyapatite nanorod embedded composite was prepared using Poly (4-vinyl pyridine-co-styrene) as a matrix with different weight percentages (wt %). The results indicated that the size and crystallinity of Carbonated hydroxyapatite nanoparticles decreases with increase in Poly (4-vinyl pyridine-co-styrene) concentration in the composite. SEM confirms the presence of carbonated hydroxyapatite nanorod crystals in Poly (4-vinyl pyridine-co-styrene) matrix. nanoCarbonated hydroxyapatite/ Poly (4-vinyl pyridine-co-styrene) composites were screened for antimicrobial activity and anti inflammatory activity.
Factors Affecting Persistence of Undergraduate Students in a Fisheries and Wildlife Program: Freshmen
Authors: Wolter Bjørn H. K. , Millenbah Kelly F. , Montgomery Robert A. , Schneider James W.
Published: September 2012

A disturbing trend in student enrollment is facing many fisheries, wildlife, and other natural resources–related disciplines. Although there has been a steady increase in the number of students entering science, technology, engineering, and mathematics (STEM) fields since the 1970s, fewer students are opting to pursue natural resources degrees. The first‐year experience is critical to student persistence, so we conducted a pilot study to better understand why students entering a fisheries and wildlife program as freshmen persisted in the major. Specific findings include the importance of small class sizes, empathetic instructors, and being socially integrated into the program (i.e., creating a strong sense of community). Students appreciated courses and experiences that engaged them in hands‐on learning activities where they could apply theoretical knowledge in practical situations, further allowing them to develop personal and professional relevancy. While many students expressed discontent with pre‐requisite courses and their rigor or perceived lack of relevancy, this was not identified as a source of attrition. While the lack of full‐time, permanent employment available to natural resource graduates was perceived as a challenge, students understood this dynamic and recognized that they would likely need to secure multiple temporary positions before obtaining a permanent job. This recognition appears to be borne of a passion for the outdoors rather than a desire to develop a career. This study has the potential to inform natural resource programs on techniques to attract, retain, and educate undergraduate students.
An Analysis of Teaching Competencies of Junior Faculty with Different Levels of Graduate Teaching Assistant Experiences
Authors: Thoron Andrew C. , Myers Brian E. , Harder Amy , Stedman Nicole , Roberts T. Grady
Published: September 2012

This casual–comparative study was conducted to determine the professional development needs of teaching faculty with fewer than 6 years of university teaching experience (n = 67). Faculty were compared on the level of teaching assistantship responsibility during their graduate degree program. The purpose of this article is to provide faculty development officers with fundamental considerations for achieving quality professional development with junior faculty based on previous teaching experience. This study found professional development needs should be tailored based on teaching assistant experiences.
Graduate Student Fellowship Program Effects on Attitude and Interest toward Science of Middle School Students
Authors: Lindner James R. , Rayfield John , Briers Gary , Johnson Larry
Published: September 2012

The purpose of this study was to describe the effects of a graduate student fellowship program on middle school students’ attitude toward science and their interest in science. Using a descriptive and correlational research design, data were collected from 588 middle school students (grades 6, 7, and 8). Participants completed a pretest and a posttest questionnaire on their attitude and interest in science. Findings showed that participants overall had a positive attitude toward and a positive interest in science; neither the attitude nor the interest changed from pretest to posttest. Within grade, attitude toward science fell slightly during 6th grade but rose slightly during 8th grade. There were no differences in pretest or posttest scores by gender. Prior research suggests that during middle school, students’ attitudes toward science and interest in science drop. An implication exists that the graduate student fellowship program had a positive influence on middle school students’ attitudes and interests in science by maintaining a high interest in science and a positive attitude toward science.
Detrimental Influence of Invasive Earthworms on North American Cold‐Temperate Forest Soils
Authors: Enerson Isabel
Published: September 2012

The topic of invasive earthworms is a timely concern that goes against many preconceived notions regarding the positive benefits of all worms. In the cold‐temperate forests of North America invasive worms are threatening forest ecosystems, due to the changes they create in the soil, including decreases in C:N ratios and leaf litter, disruption of the seed bank, and changes in soil structure and nutrient cycling. These changes in turn affect the forest ecosystem by encouraging the growth of non‐native plants, inhibiting undergrowth, decreasing biodiversity, and negatively affecting species that are sensitive to change. While the potential for remediation by acidifying the soil exists, the potential repercussions of such a change has not been researched. The key to minimizing the issue of invasive earthworms is prevention. Thus, policy and education targeted at individuals who are horticulturists, fishermen, bait shops owners, and vermiculturalists, who are commonly vectors of introduction, are critical to conserving cold‐temperate forests in North America.
Soil Genesis and Development, Lesson 1: Rocks, Minerals, and Soils
Authors: McCallister Dennis , Geiss Christoph , Mamo Martha , Kettler Timothy , Ippolito James , Reuter Ronald , Morner Patricia , Soester Jody
Published: September 2012

Most soil parent materials were rocks at some time in their history. The minerals in rocks may contribute to soil fertility and other soil properties long after the original rock is gone. Consequently, it is a valuable skill to be able to identify broad categories of rock. This lesson will discuss igneous, metamorphic, and sedimentary rocks and the minerals found in them. The lesson will also provide opportunities for students to identify rocks based on given characteristics.
Price Discrimination in the Subscription Market for Economics Journals
Authors: Zheng Yuqing , Kaiser Harry M.
Published: September 2012

We examine what factors affect the degree of price discrimination for an academic journal by analyzing data on 190 of the 208 economics journals indexed in the 2008 edition of Journal Citation Reports. We find that (i) the library‐to‐individual price ratio of a for‐profit journal is 37% higher than that of a comparable nonprofit journal because the price premium of a for‐profit journal in the library market is disproportionately larger than that in the individual market, (ii) journals with higher citations per page or impact factor are more price discriminatory, and (iii) Elsevier and Wiley‐Blackwell practice the highest degree of price discrimination of all publishers.
The “Services” Explanation for Resale Price Maintenance: Deleterious Results Missed in the Economics Literature and in Legal Decisions
Authors: da Graça Tarcisio B. , Masson Robert T.
Published: September 2012

Policy discussions and a U.S. Supreme Court decision interpret retailer services induced by retail price maintenance (RPM) as enhancing consumer surplus (CS) and welfare enhancing, marginalizing dissenting opinions that use similar models but with different parameters. However, if presales services stimulate demand by providing information about a product's value, they need not raise postsale value in use. Inframarginal consumers' presales perceived value may increase, but their postsale value may be unchanged, so their supposed CS gains are ephemeral, and their actual surplus falls proportional to price increase. We show that, even adding in gains to marginal consumers, effects on CS are far more negative than conceived of in this literature. Consequently, in a rule‐of‐reason antitrust environment, if RPM is challenged without alleging collusion or exclusion, presales demand‐inducing information provision is a flimsy defense if CS is the standard and not always convincing if total surplus is the standard.
The relative importance of impacts from climate change vs. emissions change on air pollution levels in the 21st century
Authors: Hedegaard G. B. , Christensen J. H. , Brandt J.
Published: September 2012

Abstract. So far several studies have analysed the impacts of climate change on future air pollution levels. Significant changes due to impacts of climate change have been made clear. Nevertheless, these changes are not yet included in national, regional or global air pollution reduction strategies. The changes in future air pollution levels are caused by both impacts from climate change and anthropogenic emission changes and the importance of these signals needs to be quantified and compared. In this study we use the Danish Eulerian Hemispheric Model (DEHM) driven on meteorological input data from the coupled Atmosphere-Ocean General Circulation Model ECHAM5/MPI-OM and forced with the newly developed RCP4.5 emissions. The relative importance of the climate signal and the signal from changes in anthropogenic emissions on the future ozone, black carbon (BC), total particulate matter with a diameter below 2.5 μm (total PM2.5 including BC, primary organic carbon (OC), mineral dust and secondary inorganic aerosols (SIA)) and total nitrogen (including NHx + NOy) has been determined. For ozone the impacts of anthropogenic emissions dominates though a climate penalty is found in the Arctic region and the Northwestern Europe where the signal from climate change dampens the effect from the projected emission reductions of anthropogenic ozone precursors. The investigated particles are even more dominated by the impacts from emission changes. For black carbon the emission signal dominates slightly at high latitudes increasing to be up to an order of magnitude larger close to the emission sources in temperate and subtropical areas. Including all particulate matter with a diameter below 2.5 μm (total PM2.5) enhances the dominance from emissions change. In contrast, total nitrogen (NHx + NOy) in parts of the Arctic and at low latitudes is dominated by impacts of climate change.
Airborne sunphotometer PLASMA: concept, measurements, comparison of aerosol extinction vertical profile with lidar
Authors: Karol Y. , Tanré D. , Goloub P. , Vervaerde C. , Balois J. Y. , Blarel L. , Podvin T. , Mortier A. , Chaikovsky A.
Published: September 2012

Abstract. A 15-channel airborne sun tracking photometer has been developed. The instrument provides aerosol optical depths over a wide spectral range (0.34–2.25 μm) with an accuracy of ΔAOD from 0.005 to 0.01. Doing measurements at different altitudes allow us to derive the aerosol extinction vertical profile. Thanks to the wide spectral range of the instrument, information on the aerosol size distribution along the vertical is also available.
Development of a low cost robot system for autonomous measuring of spatial field distributions
Authors: Schetelig B. , Parr S. , Potthast S. , Dickmann S.
Published: September 2012

Abstract. A new kind of a modular multi-purpose robot system is developed to measure the spatial field distributions of very large as well as of small and crowded areas. The probe is automatically placed at a number of pre-defined positions where measurements are carried out. The advantages of this system are its very low influence on the measured field as well as its wide area of possible applications. In addition, the initial costs are quite low. In this paper the theory underlying the measurement principle is explained. The accuracy is analyzed and sample measurements are presented.
A context management system for a cost-efficient smart home platform
Authors: Schneider J. , Klein A. , Mannweiler C. , Schotten H. D.
Published: September 2012

Abstract. This paper presents an overview of state-of-the-art architectures for integrating wireless sensor and actuators networks into the Future Internet. Furthermore, we will address advantages and disadvantages of the different architectures. With respect to these criteria, we develop a new architecture overcoming these weaknesses. Our system, called Smart Home Context Management System, will be used for intelligent home utilities, appliances, and electronics and includes physical, logical as well as network context sources within one concept. It considers important aspects and requirements of modern context management systems for smart X applications: plug and play as well as plug and trust capabilities, scalability, extensibility, security, and adaptability. As such, it is able to control roller blinds, heating systems as well as learn, for example, the user's taste w.r.t. to home entertainment (music, videos, etc.). Moreover, Smart Grid applications and Ambient Assisted Living (AAL) functions are applicable. With respect to AAL, we included an Emergency Handling function. It assures that emergency calls (police, ambulance or fire department) are processed appropriately. Our concept is based on a centralized Context Broker architecture, enhanced by a distributed Context Broker system. The goal of this concept is to develop a simple, low-priced, multi-functional, and save architecture affordable for everybody. Individual components of the architecture are well tested. Implementation and testing of the architecture as a whole is in progress.
Automatic focus algorithms for TDI X-Ray image reconstruction
Authors: Dörr J. , Rosenbaum M. , Sauer-Greff W. , Urbansky R.
Published: September 2012

Abstract. In food industry, most products are checked by X-rays for contaminations. These X-ray machines continuously scan the product passing through. To minimize the required X-ray power, a Time, Delay and Integration (TDI) CCD-sensor is used to capture the image. While the product moves across the sensor area, the X-ray angle changes during the pass. As a countermeasure, adjusting the sensor shift speed on a single focal plane of the product can be selected. However, the changing angle result in a blurred image in dependance to the thickness of the product. This so-called ''laminographic effect'' can be compensated individually for one plane by inverse filtering. As the plane of contamination is unknown, the blurred image will be inversely filtered for different planes, but only one of these images shows the correctly focussed object. If the correct image can be found, the plane containing the contamination is identified. In this contribution we demonstrate how the correctly focussed images can be found by analyzing the images of all planes. Different characteristics for correctly and incorrectly focussed planes like sharpness, number of objects and edges are investigated by using image processing algorithms.
The influence of different PAST-based subspace trackers on DaPT parameter estimation
Authors: Lechtenberg M. , Götze J.
Published: September 2012

Abstract. In the context of parameter estimation, subspace-based methods like ESPRIT have become common. They require a subspace separation e.g. based on eigenvalue/-vector decomposition. In time-varying environments, this can be done by subspace trackers. One class of these is based on the PAST algorithm. Our non-linear parameter estimation algorithm DaPT builds on-top of the ESPRIT algorithm. Evaluation of the different variants of the PAST algorithm shows which variant of the PAST algorithm is worthwhile in the context of frequency estimation.
Application of syndrome based Turbo decoding with adaptive computational complexity in LTE downlink
Authors: Geldmacher J. , Hueske K. , Kosakowski M. , Götze J.
Published: September 2012

Abstract. This paper describes the application of an adaptive complexity decoder for the Long Term Evolution (LTE) downlink Turbo code. The proposed decoding approach is based on the block syndrome decoding principle and enables adaptive reduction of decoding effort depending on current SNR and iteration number with negligible influence on decoding performance. Numerical results in context of LTE downlink using typical mobile channels are used to demonstrate the efficiency of the approach.
Statistics of long-term ionospheric measurements
Authors: Damboldt T. , Suessmann P.
Published: September 2012

Abstract. It is shown that after elimination of the dominant influence of solar activity, the height hmF2 of the maximum ionisation of the ionosphere (which is inversely linearly related to M(3000)F2 as described for example by the Shimazaki formula) shows a marked decrease during the recent solar minimum (2005 to 2009) of about 20 km. This is in accordance with results of studies of the decreased neutral density of the lower thermosphere and the density decrease at about 400 km during the unusual recent solar minimum. It is also shown that there is a trend reversal in the height of the ionosphere hmF2 in about 1963/1964 with a negative trend from 1942 to 1963 and a positive trend from 1964 to 2005. This is in contrast to the results reported in most other publications of ionospheric long-term trends. There is no significant trend in foF2 and, particularly, none of the effects described above for hmF2 could be found in foF2.
The 8-h tide in the mesosphere and lower thermosphere over Collm (51.3° N; 13.0° E), 2004–2011
Authors: Jacobi Ch. , Fytterer T.
Published: September 2012

Abstract. The horizontal winds in the mesosphere and lower thermosphere (MLT) at heights of about 80–100 km have been measured continuously since summer 2004 using an all-sky 36.2 MHz VHF meteor radar at Collm, Germany (51.3° N, 13° E). A climatology of the 8-h solar tide has been constructed from these data. The amplitude shows a seasonal behaviour with maximum values during the equinoxes, and it is generally increasing with altitude. The largest amplitudes are measured in autumn, partly reaching values up to 15 m s−1. The phase, defined as the time of maximum eastward or northward wind, respectively, has earlier values in winter and later ones in summer. Except for summer, the phase difference between the zonal and meridional components is close to +2 h, indicating circular polarization of the tidal components. The vertical wavelengths are short in summer (~20 km) but significantly longer during the rest of the year. The terdiurnal tide is generally assumed to originate from either a terdiurnal component of solar heating or nonlinear interaction between the diurnal and semidiurnal tide. Analysing monthly means reveals positive correlation during the spring maximum, but negative correlation in autumn.
Data analysis of low frequency transmitter signals received at a midlatitude site with regard to planetary wave activity
Authors: Schmitter E. D.
Published: September 2012

Abstract. More than 2 yr of continuously recorded signal amplitude data from the MSK transmitters NRK/TFK (37.5 kHz, Iceland) and NSY (45.9 kHz, Sicily) received at (52° N 8° E) in the time range from August 2009 to September 2011 are analyzed with regard to planetary wave activity. Wavelet analysis of the day/night amplitude ratio reveals clear evidence of quasi 16 day periods mainly during winter time as well as traces of 5 and 10 day periods on both paths. The amplitude ratio is well correlated to the typical stratospheric (10 hPa) seasonal temperature profile – more clearly to be seen on the northern path. The results are in line and an extension of manifold research with regard of ionospheric absorption phenomena caused by atmospheric wave activity. Continuous monitoring of transmitters in the 40 kHz frequency range proved as an inexpensive tool for investigating mesospheric response to forcing from below.
Numerical modeling of solar wind influences on the dynamics of the high-latitude upper atmosphere
Authors: Förster M. , Prokhorov B. E. , Namgaladze A. A. , Holschneider M.
Published: September 2012

Abstract. Neutral thermospheric wind patterns at high latitudes obtained from cross-track acceleration measurements of the CHAMP satellite above both polar regions are used to deduce statistical neutral wind vorticity distributions and were analyzed in their dependence on the Interplanetary Magnetic Field (IMF). The average pattern confirms the large duskside anticyclonic vortex seen in the average wind pattern and reveals a positive (cyclonic) vorticity on the dawnside, which is almost equal in magnitude to the duskside negative one. The IMF dependence of the vorticity pattern resembles the characteristic field-aligned current (FAC) and ionospheric plasma drift pattern known from various statistical studies obtained under the same sorting conditions as, e.g., the EDI Cluster statistical drift pattern. There is evidence for hemispheric differences in the average magnitudes of the statistical patterns both for plasma drift and even more for the neutral wind vorticity. The paper aims at a better understanding of the globally interconnected complex plasma physical and electrodynamic processes of Earth's upper atmosphere by means of first-principle numerical modeling using the Upper Atmosphere Model (UAM). The simulations of, e.g., thermospheric neutral wind and mass density at high latitudes are compared with CHAMP observations for varying IMF conditions. They show an immediate response of the upper atmosphere and its high sensitivity to IMF changes in strength and orientation.
A cooperative transponder system for improved traffic safety, localizing road users in the 5 GHz band
Authors: Schaffer B. , Kalverkamp G. , Chaabane M. , Biebl E. M.
Published: September 2012

Abstract. We present a multi-user cooperative mobile transponder system which enables cars to localize pedestrians, bicyclists and other road users in order to improve traffic safety. The system operates at a center frequency of 5.768 GHz, offering the ability to test precision localization technology at frequencies close to the newly designated automotive safety related bands around 5.9 GHz. By carrying out a roundtrip time of flight measurement, the sensor can determine the distance from the onboard localization unit of a car to a road user who is equipped with an active transponder, employing the idea of a secondary radar and pulse compression. The onboard unit sends out a pseudo noise coded interrogation pulse, which is answered by one or more transponders after a short waiting time. Each transponder uses a different waiting time in order to allow for time division multiple access. We present the system setup as well as range measurement results, achieving an accuracy up to centimeters for the distance measurement and a range in the order of hundred meters. We also discuss the effect of clock drift and offset on distance accuracy for different waiting times and show how the system can be improved to further increase precision in a multiuser environment.
Entwurfskonzept einer Car2Car-Multiband-Dachantenne
Authors: Wang Y. , Reit M. , Mathis W.
Published: September 2012

Abstract. Due to the vastly increasing use of wireless services in the car, such as WiFi, Car2Car and LTE, the requirements on bandwidth and radiation pattern of the roof antenna systems become more challenging. In this work, a design concept for multi-band roof antenna systems is presented. We aim to get a higher bandwidth and an almost circular radiation pattern on the horizontal plane. Moreover, the antenna length is considered in order to fulfill the requirements set by construction ECE-regulations (ECE, 2010). The applicability of the design concept is not limited to multi-band roof antennas, it can also be used for a general wideband antenna design. For illustration of this concept, a multi-band roof antenna with a bandwidth of 780 MHz to 5.9 GHz and a near circular radiation pattern with an average gain of G = 3 dBi (at 5.9 GHz) on the horizontal plane is designed. The simulation and measurement results are presented.
Properties of axial surface waves along dielectrically coated conducting cylinders
Authors: Siart U. , Adrian S. , Eibert T.
Published: September 2012

Abstract. In this paper the fundamental properties of surface waves along conducting cylinders with and without dielectric coating are investigated for cylinder diameters in the centimeter range and frequencies in the gigahertz range and higher. Analytical results for the phase constant and attenuation versus the cylinder radius are derived and cutoff frequencies of various TE, TM, and hybrid waves are computed. The radial power distribution is computed in order to investigate the spatial extent of the wave fields.
Improved measurement surface for MEG using magnetic-dipole sources and a spherical-multipole expansion
Authors: Argin F. , Ahrens H. , Klinkenbusch L.
Published: September 2012

Abstract. The multipole representation of Magnetoencephalography (MEG) signals is known as a useful tool for distinguishing between magnetic fields arising from the brain and external disturbances. In this contribution we extend this concept and show that a closed double-layer surface with magnetometer probes is better suited to determine the corresponding multipole amplitudes αlm than a conventional single-layer surface with gradiometers and magnetometer probes. For two different source configurations we show that the αlm rapidly converge to the exact values. This proof of concept motivates to further optimize the geometry of the double-layer surface and the sensors' positions.
The exponential eigenmodes of the carbon-climate system
Authors: Raupach M. R.
Published: September 2012

Abstract. Several basic ratios describing the carbon-climate system are observed to adopt relatively steady values. Examples include the CO2 airborne fraction (the fraction of the total anthropogenic CO2 emission flux that accumulates in the atmosphere) and the ratio T/QE of warming (T) to cumulative total CO2 emissions (QE). This paper explores the reason for such near-constancy in the past, and its likely limitations in future. The contemporary carbon-climate system is often approximated as a first-order linear system, for example in response-function descriptions. All such linear systems have exponential eigenfunctions in time (an eigenfunction being one that, if applied to the system as a forcing, produces a response of the same shape). This implies that, if the carbon-climate system is idealised as a linear system (Lin) forced by exponentially growing CO2 emissions (Exp), then all ratios among fluxes and perturbation state variables are constant. Important cases are the CO2 airborne fraction (AF), the cumulative airborne fraction (CAF), other CO2 partition fractions and cumulative partition fractions into land and ocean stores, the CO2 sink uptake rate (kS, the combined land and ocean CO2 sink flux per unit excess atmospheric CO2), and the ratio T/QE. Further, the AF and the CAF are equal. The Lin and Exp idealisations apply approximately (but not exactly) to the carbon-climate system in the period from the start of industrialisation (nominally 1750) to the present, consistent with the observed near-constancy of the AF, CAF and T/QE in this period. A nonlinear carbon-climate model is used to explore how the likely future breakdown of both the Lin and Exp idealisations will cause the AF, CAF and kS to depart significantly from constancy, in ways that depend on CO2 emissions scenarios. However, T/QE remains approximately constant in typical scenarios, because of compensating interactions between emissions trajectories, carbon-cycle dynamics and non-CO2 gases. This theory assists in establishing both the basis and limits of the widely-assumed proportionality between T and QE, at about 2 K per trillion tonnes of carbon.
Ammonoid multi-extinction crises during the Late Pliensbachian – Toarcian and carbon cycle instabilities
Authors: Guex J. , Bartolini A. , Spangenberg J. , Vicente J.-C. , Schaltegger U.
Published: September 2012

Abstract. Five crises affecting ammonite evolution occurred during the Late Pliensbachian to Late Toarcian stages (Early Jurassic). The first two (Gibbosus and end-Spinatum zones) occurred during highly cold and regressive conditions which were followed by a global anoxic event generated during a supergreenhouse warm event (Levisoni subzone) concomitant with a worldwide transgressive event. The last two (Late Variabilis and Late Insigne zones) are related to regressive events. We present new carbon isotope data from Southern Peru that demonstrate that most of the major Toarcian crises affecting ammonite evolution can be correlated with the variations affecting the δ13C during that unstable period. The morphogenetic reactions of the ammonites during the five different upper Liassic critical episodes are analysed, showing how this group can be used as stress indicators.
M/G/1 Queues with Postponed Interruptions
Authors: Blanc Hans (J. P. C.)
Published: September 2012

This paper studies the effect of postponing interruptions of the service in M/G/1 queueing systems until the end of the service in progress. The waiting and sojourn times in systems with postponement are compared with those in comparable systems without post-ponement, both for the case that interruptions can only occur during busy times of the server and for the case that interruptions are also possible during idle times of the server.
A Numerical Study of the Nonlinear Reaction-Diffusion Equation with Different Type of Absorbent Term by Homotopy Analysis Method
Authors: Gupta Praveen Kumar , Verma Swati
Published: September 2012

In this paper, based on the homotopy analysis method (HAM), a new powerful algorithm is used for the solution of the nonlinear reaction-diffusion equation. The algorithm presents the procedure of constructing a set of base functions and gives the high-order deformation equation in a simple form. Different from all other analytic methods, it provides us with a simple way to adjust and control the convergence region of the solution series by introducing an auxiliary parameter h. The solutions of the problem of presence and absence of absorbent term and external force for different particular cases are presented graphically.
Dufour and Soret Effects on the Thermosolutal Instability of Rivlin– Ericksen Elastico–Viscous Fluid in Porous Medium
Authors: Chand Ramesh , Rana Gian Chand
Published: September 2012

Dufour and Soret effects on the convection in a horizontal layer of Rivlin-Ericksen elastico- viscous fluid in porous medium are considered. For the porous medium, the Darcy model is used. A linear stability analysis based upon normal mode analysis is employed to find a solution of the fluid layer confined between two free boundaries. The onset criterion for stationary and oscillatory convection has been derived analytically, and graphs have been plotted, giving various numerical values to various parameters, to depict the stability characteristics. The effects of the Dufour parameter, Soret parameter, solutal Rayleigh number, and Lewis number on stationary convection have been investigated.