Showing papers by "Mobil published in 2008"

Using the Timing Information of Heartbeats as an Entity Identifier to Secure Body Sensor Network

Abstract: Security of the emerging body sensor network (BSN) in telemedicine applications is a crucial problem because personal medical information must be protected against flaws and misdeeds. The solution is, however, nontrivial because lightweight mechanisms have to be deployed to meet the stringent resource constraints of these networks. It has been suggested that the inherent ability of human body to transfer information is a unique and resource-saving method to secure wireless communications within a BSN. For example, physiological characteristics can be captured by individual sensors of a BSN to generate entity identifiers (EIs) for identifying nodes and even securing keying materials, i.e., by a biometric approach. This study demonstrates the performance analysis of such a biometric trait, i.e., the interpulse intervals (IPIs) of heartbeats that were calculated from electrocardiogram and photoplethysmogram of 99 subjects. Based on the characteristics of IPIs, a lightweight generation scheme of EIs is proposed. Individual randomness and group similarity of the generated EIs are then evaluated. False acceptance rate and false rejection rate are also calculated to measure the effectiveness of the proposed identification system. The results suggest that the readily available IPI information can be a good source for generating EIs among BSN nodes.

Implementation of the EOG-Based Human Computer Interface System

Abstract: Bio-based human computer interface(HCI) has attracted more and more attention of researches all over the world in recent years. In this paper, an EOG-based HCI system is introduced. It is composed of three parts: EOG amplifying and acquisition, EOG pattern recognition and control command output. Three plane electrodes are employed to detects the EOG signals, which contains the information related to the eye blinking and vertical( or horizontal ) eye movements referred to pre-designed command table. An online signal processing algorithm is designated to get the command information contained in EOG signals, and these commands could be used to control the computer or other instruments. Based on this HCI system, the remote control experiments driven by EOG are realized.

The CO2 exchange of biological soil crusts in a semiarid grass-shrubland at the northern transition zone of the Negev desert, Israel

Abstract: . Biological soil crusts (BSC) contribute significantly to the soil surface cover in many dryland ecosystems. A mixed type of BSC, which consists of cyanobacteria, mosses and cyanolichens, constitutes more than 60% of ground cover in the semiarid grass-shrub steppe at Sayeret Shaked in the northern Negev Desert, Israel. This study aimed at parameterizing the carbon sink capacity of well-developed BSC in undisturbed steppe systems. Mobile enclosures on permanent soil borne collars were used to investigate BSC-related CO2 fluxes in situ and with natural moisture supply during 10 two-day field campaigns within seven months from fall 2001 to summer 2002. Highest BSC-related CO2 deposition between –11.31 and –17.56 mmol m−2 per 15 h was found with BSC activated from rain and dew during the peak of the winter rain season. Net CO2 deposition by BSC was calculated to compensate 120%, –26%, and less than 3% of the concurrent soil CO2 efflux from November–January, February–May and November–May, respectively. Thus, BSC effectively compensated soil CO2 effluxes when CO2 uptake by vascular vegetation was probably at its low point. Nighttime respiratory emission reduced daily BSC-related CO2 deposition within the period November–January by 11–123% and on average by 27%. The analysis of CO2 fluxes and water inputs from the various sources showed that the bulk of BSC-related CO2 deposition occurs during periods with frequent rain events and subsequent condensation from water accumulated in the upper soil layers. Significant BSC activity on days without detectable atmospheric water supply emphasized the importance of high soil moisture contents as additional water source for soil-dwelling BSC, whereas activity upon dew formation at low soil water contents was not of major importance for BSC-related CO2 deposition. However, dew may still be important in attaining a pre-activated status during the transition from a long "summer" anabiosis towards the first winter rain.

Alkylaromatic lubricant fluids

Abstract: Provided are alkylaromatic compositions and processes for producing them. The alkylaromatic compositions include an aromatic moiety other than unsubstituted naphthalene; and an alkyl moiety having a carbon atom number in the range between 12 to 40, wherein said alkyl moiety is attached to said aromatic moiety such that at least 25 mol% of the benzylic carbons are quaternary. The process for producing the alkylaromatic compositions include contacting at least one an aromatic compound and a mono-olefin having a carbon atom number in the range between 12 to 40 in the presence of an acidic alkylation catalyst under alkylation conditions, wherein at least 50 mol% of the mono-olefin structure comprises a vinylidenyl structure, and thereby producing said alkylaromatic compound having at least 25 mol% of benzylic carbons that are quaternary. The alkylaromatic compositions disclosed herein are liquids that have improved thermo- and oxidative stability and pour point.

Method and system for updating media lists in portable media devices

Abstract: A method and apparatus for updating a media list or a media list collection of a portable media player device is disclosed herein. In various embodiments, the updates are generated by a proxy or a third party server, based at least in part on data gathered for media preferences for a user of the portable media play device and one or more other users of one or more portable media player devices. In various embodiments, the method is practiced respecting the access rights of the media files (if access rights are required). Other embodiments may also be described and claimed.

Frequency Offset Estimation and Training Sequence Design for MIMO OFDM

Abstract: This paper addresses carrier frequency offset (CFO) estimation and training sequence design for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems over frequency selective fading channels. By exploiting the orthogonality of the training sequences in the frequency domain, integer. CFO (ICFO) is estimated. With the uniformly spaced non-zero pilots in the training sequences and the corresponding geometric mapping, fractional CFO (FCFO) is estimated through the roots of a real polynomial. Furthermore, the condition for the training sequences to guarantee estimation identifiability is developed. Through the analysis of the correlation property of the training sequences, two types of sub-optimal training sequences generated from the Chu sequence are constructed. Simulation results verify the good performance of the CFO estimator assisted by the proposed training sequences.

A necessary and sufficient condition for determining the girth of quasi-cyclic LDPC codes

Abstract: The parity-check matrix of a quasi-cyclic low- density parity-check (QC-LDPC) code can be compactly represented by a polynomial parity-check matrix. By using this compact representation, we derive a necessary and sufficient condition for determining the girth of QC-LDPC codes in a systematic way. The new condition avoids an explicit enumeration of cycles for determining the girth of codes, and thus can be well employed to generate QC-LDPC codes with large girth.

Kinetics of Ethylene Polymerization Reactions with Chromium Oxide Catalysts

Abstract: Principal kinetic data are presented for ethylene homopolymerization and ethylene/1-hexene copolymerization reactions with two types of chromium oxide catalyst. The reaction rate of the homopolymerization reaction is first order with respect to ethylene concentration (both for gas-phase and slurry reactions); its effective activation energy is 10.2 kcal/mol (42.8 kJ/mol). The r 1 value for ethylene/1-hexene copolymerization reactions with the catalysts is ∼30, which places these catalysts in terms of efficiency of α-olefin copolymerization with ethylene between metallocene catalysts (r 1 ∼ 20) and Ti-based Ziegler-Natta catalysts (r 1 in the 80-120 range). GPC, DSC, and Crystaf data for ethylene/1-hexene copolymers of different compositions produced with the catalysts show that the reaction products have broad molecular weight and compositional distributions. A combination of kinetic data and structural data for the copolymers provided detailed information about the frequency of chain transfer reactions for several types of active centers present in the catalysts, their copolymerization efficiency, and stability.

Control of wireless connection for a portable media player

Abstract: A portable media player that provides for wireless connectivity is disclosed. In some examples, the portable media player contains a button that causes the player to search for, connect with, and disconnect from wireless networks. In some examples, the button provides indicators of the connectivity of the player, such as different colors or modes of illumination. In some examples, the functionality of the button changes depending on the connectivity of the player or characteristics of the playback or navigation of media within the player. Other embodiments are also described and claimed.

Media playing on a portable media player including shop and play remote media

Abstract: A software and/or hardware facility that enables shop and play remote media using a portable media player is disclosed. Shopping may include, but is not limited to, allowing a user to identify media and acquire (via download or stream) the media to a portable media player for free or for compensation. The facility in some embodiments, allows a user to shop for media on a network site or service using a portable media player via a wired or wireless connection. The facility in some embodiments, automatically presents a user with media available from a network site or service that is related to the context of the user's use of the portable media player, such as when a user navigates or otherwise uses the portable media player. Other embodiments are described and claimed.

Simplified Frequency Offset Estimation for MIMO OFDM Systems

Abstract: This paper addresses a simplified frequency offset estimator for multiple-input-multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) systems over frequency-selective fading channels. By exploiting the good correlation property of the training sequences, which are constructed from the Chu sequence, carrier frequency offset (CFO) estimation is obtained through factor decomposition for the derivative of the cost function with great complexity reduction. The mean square error (MSE) of the CFO estimation is derived to optimize the key parameter of the simplified estimator as well as to evaluate the estimator performance. Simulation results confirm the good performance of the training-assisted CFO estimator.

Capacity analysis of generalized distributed antenna systems using approximation distributions

Abstract: Compared to the central antenna system (CAS), the distributed antenna system (DAS) improves the communication performance greatly because of the macro-diversity and the micro-diversity. However, the channel between the mobile terminal and a remote access unit (RAU) in the DAS is a composite fading channel, which makes it be difficult to achieve a closed form expression in capacity analysis. In this paper, Patnaik?s and Pearson?s methods are employed to achieve approximation probability distribution function (PDF) of the channel, by which the ergodic capacity of the generalized DAS (GDAS) is achieved easily. Analysis and simulations show that both the two methods can achieve satisfying results of the channel capacity, which are more accurate than that of the commonly used Jensen inequality.

Laser arrangement for marking, roughing, hardening and welding the surface of a workpiece, comprises laser source, optical arrangement for focusing and direction controlling of laser beam, supporting area for the workpiece, and window

Abstract: The laser arrangement for marking, roughing, hardening and welding the surface of a workpiece, comprises a laser source, an optical arrangement for focusing and direction controlling of laser beam, a support area for the workpiece, a window (FE) permeable for laser light arranged in the support area, an extraction unit arranged above the optical arrangement and below the window, unit for the production of air flow between the optical arrangement and the window, a transparent cover for the laser light arranged between the optical arrangement and the window, and a movable cover. The laser arrangement for marking, roughing, hardening and welding the surface of a workpiece, comprises a laser source, an optical arrangement for focusing and direction controlling of laser beam, a support area for the workpiece, a window (FE) permeable for laser light, arranged in the support area, an extraction unit arranged above the optical arrangement and below the window, unit for the production of air flow between the optical arrangement and the window, a transparent cover for the laser light, arranged between the optical arrangement and the window, a movable cover, which surrounds the workpiece, and position sensors, which hold the position of the cover and which delivers sensor signals at a security supervision arrangement. The optical arrangement is arranged below the window and the workpiece is arranged over the window on the support area. The size of the window is changeable. The window is implemented as breakthrough open towards bottom through the support area and has a table arrangement out of modules variably assembled in a module. The support area is formed on a processing disk (AP) with regular reinforcement structure and is terminated on a side between the optical arrangement and the window. The gas flow is produced from the optical arrangement path directed in the direction of the window. The cover is movable relative to the window. The focus position of the focused laser beam is adjustable vertical to the support area. The position of the optical arrangement is changeable vertical to the support area. The optical arrangement is summarized in a laser head housing, which is taken from the position under the window and which is applicable as hand-operated device (HG). The movable cover is intended over the support area.

Near-Optimal Power Allocation for MIMO Systems with Partial CSI Feedback

Abstract: This paper studies the power allocation problems for a multiple-input multiple-output (MIMO) antenna system with various partial channel state information (CSI) feedback. Through the derivation of new upper bounds of the ergodic capacity for both the cases of channel mean and covariance information feedback, we devise simple closed-form power allocation solutions for the MIMO systems with two transmit antennas. These results are then extended to systems with any number of antennas at both sides. Unlike previous approaches which require computationally complex numerical optimizations over random processes, our solutions in closed-form offer a water-filling interpretation and perform nearly the same as the global optimum.

Optimized Big Bore Gas Wells For Qatar North Field

Abstract: An extensive big bore gas well drilling and completions program has been in progress since 2002 to develop the giant North Field, Offshore Qatar. This is the world’s largest non-associated gas field and contains approximately 900 Tcf of abnormally pressured natural gas producing from thick, Khuff carbonate reservoirs.

Action-based menus for a portable media device

Abstract: A software and/or hardware facility for presenting action-based menus on a portable media player. An action-based menu is a list of action options contextually displayed to a user of the portable media player that includes actions that are relevant to the particular piece of media or group of media. Each action in the action-based menu is selectable by the user, and the facility initiates an activity corresponding to a selected action. Other embodiments are disclosed and claimed.

Anordnung und Verfahren zur Beschriftung einer Oberfläche eines Substrats

Abstract: Fur die Beschriftung eines lasertransparenten Substrats mittels eines Lasertransferverfahrens wird vorgeschlagen, fur das zu transferierende Beschichtungsmaterial einen metallischen Trager zu wahlen. Vorzugsweise ist das Beschichtungsmaterial durch eine mittels Anodisieren des Tragermetalls gebildete Schicht eines Metalloxids, insbesondere eine eloxierte Aluminiumschicht auf einem Aluminiumtrager gebildet. Eine besonders hohe Abriebfestigkeit ergibt sich, wenn der Trager mit dem Beschichtungsmaterial an die zu beschriftende Substratoberflache angelegt und wahrend des Beschriftungsvorgangs angedruckt wird.

Parallel multiplexing scheduling in DAS with partial channel state information

Abstract: Transmit diversity (TD) is an efficient method to yield channel capacity in single-user multi-antenna system. In this paper, we first analyze scheduling based on TD in multi-user distributed antenna systems (DAS). We show that average throughput of the system grows with the total number of remote access units (RAUs) in DAS. However, when the total number of RAUs is constant, TD has little improvement to average throughput. Then, parallel multiplexing scheduling (PMS) is proposed based on multi-user multiplexing in spatial domain to improve average throughput of DAS. In PMS, multiple users are selected to transmit simultaneously at each slot rather than only one user occupies all channel resources in scheduling based on TD. Thus PMS achieves a better performance than scheduling based on TD does. Finally, an optimized PMS (OPMS) scheme is presented, in which all users are classified as multiple scheduling user groups (SUGs), and then parallel scheduling is implemented among the SUGs. OPMS inherits all characteristics of PMS but only partial channel state information (CSI) is fed back to base station (BS).

Study on Capacity of BLAST System with Error Propagation

Abstract: The capacity of the BLAST system is larger than that of a single antenna system, but error propagation affects the BLAST architecture capacity. The ergodic capacity is analyzed of BLAST architecture with error propagation (EP-BLAST). We find that in EP-BLAST system, the diversity orders of all symbols transmitted by different antenna are same, which are equal to the smallest diversity order of the symbol in error-free BLAST (EF-BLAST). Since it is difficult to obtain a closed-form solution of the ergodic capacity of EP-BLAST, the upper-bound of the capacity is achieved in this paper.