The importance of access to information and knowledge coordination on quality and economic benefits obtained from Six Sigma

Wireless Networks - This paper presents a structural equation model that relates knowledge coordination with access to information in the process of implementing Six Sigma and their impact on the...     

Construction of baselines for VoIP traffic management on open MANs

In the last century, owing to the constant evolution of technologies telecommunication networks have become increasingly robust, being able to support multiple services. These services are part of the heterogeneous network traffic that can be carried through the Internet. Many of these services, including VoIP, are latency sensitive. In other words, this means that their quality depends directly on the network quality of service. Since users tend to become more sensitive with the instability and unavailability of the network, it is important to improve traffic management. A particular type of data that could be used to improve VoIP traffic management is the Internet Protocol Detail Record (IPDR). IPDRs are tickets created by all VoIP call attempts which contain a group of information related to the call history. Because of its full range of information, IPDRs can be used to create VoIP traffic baselines. This paper presents the development of baselines based on IPDRs to support VoIP traffic management in open‐access Metropolitan Area Networks (MAN). Copyright © 2013 John Wiley & Sons, Ltd.     

Radiation Pattern of Wearable Antennas: A Statistical Analysis of the Influence of the Human Body

This paper explores a statistical approach for modelling antennas?? behaviour in the vicinity of the human body. The statistics of radiation patterns, i.e., average and standard deviation, have been calculated for Uniform and Rayleigh distance Distributions of the antenna to the body. The coupling between the body and the antenna, and the reduction of antenna efficiency, lead to a distortion of the radiation pattern, which depends on the distance as well as on the location on the body. A patch antenna operating at 2.45?GHz, on the head, chest, arm, and leg was simulated in computer simulation technology (CST), using a voxel model. Results show that the relative change of the average radiation pattern for an antenna located on the chest can reach 24?%. The study was complemented with measurements, showing that, in the area of interest for on-body communications, an average difference between CST and measurements of 0.9?dB is found which can be considered very good.     

Reducing leakage power with BTB access prediction

This paper investigates three architectural methods to reduce the leakage power dissipated by the BTB data array. The first method (called here window) periodically places the entire BTB data array into drowsy mode. A drowsy entry is woken up by the first access in the time interval and remains active for the remainder of the interval (window). There is an associated performance loss which is related to the size of the window, since there is a delay when a specific line must be woken up. The second method, awake line buffer (ALB), limits the number of active BTB entries to a predetermined maximum. While this reduces power dissipation it comes with a performance penalty that is relative to the size of the buffer. ALB, however, reduces the power dissipation of the data array more than the window method. The third method, 2-level ALB (2L-ALB), uses a two level buffer with the identical number of combined entries as the previous method. This method exploits the fact that many branches operate numerous times in a fixed sequence. By predicting the next BTB access, 2L-ALB achieves further reduction in leakage power without incurring any further performance loss, compared to the ALB method.     

Adaptive filtering of evoked potentials with radial-basis-function neural network prefilter

Evoked potentials (EPs) are time-varying signals typically buried in relatively large background noise. To extract the EP more effectively from noise, we had previously developed an approach using an adaptive signal enhancer (ASE) (Chen et al., 1995). ASE requires a proper reference input signal for its optimal performance. Ensemble- and moving window-averages were formerly used with good results. In this paper, we present a new method to provide even more effective reference inputs for the ASE. Specifically, a Gaussian radial basis function neural network (RBFNN) was used to preprocess raw EP signals before serving as the reference input. Since the RBFNN has built-in nonlinear activation functions that enable it to closely fit any function mapping, the output of RBFNN can effectively track the signal variations of EP. Results confirmed the superior performance of ASE with RBFNN over the previous method.     

Dye‐Doped Polyhedral Oligomeric Silsesquioxane (POSS)‐Modified Polymeric Matrices for Highly Efficient and Photostable Solid‐State Lasers

Here, the design, synthesis, and characterization of laser nanomaterials based on dye‐doped methyl methacrylate (MMA) crosslinked with octa(propyl‐methacrylate) polyhedral oligomeric silsesquioxane (8MMAPOSS) is reported in relation to their composition and structure. The influence of the silicon content on the laser action of the dye pyrromethene 567 (PM567) is analyzed in a systematic way by increasing the weight proportion of POSS from 1 to 50%. The influence of the inorganic network structure is studied by replacing the 8MMAPOSS comonomer by both the monofunctionalized heptaisobutyl‐methacryl‐POSS (1MMAPOSS), which defines the nanostructured linear network with the POSS cages appearing as pendant groups of the polymeric chains, and also by a new 8‐hydrogenated POSS incorporated as additive to the polymeric matrices. The new materials exhibit enhanced thermal, optical, and mechanical properties with respect to the pure organic polymers. The organization of the molecular units in these nanomaterials is studied through a structural analysis by solid‐state NMR. The domain size of the dispersed phase assures a homogeneous distribution of POSS into the polymer, thus, a continuous phase corresponding to the organic matrix incorporates these nanometer‐sized POSS crosslinkers at a molecular level, in agreement with the transparency of the samples. The silicon–oxygen core framework has to be covalently bonded into the polymer backbone instead of being a simple additive and both the silica content and crosslinked degree exhibit a critical influence on the laser action.     

Optimising Channel Assignments for Private Mobile Radio Networks in the UHF 2 Band

Private mobile radio (PMR) services are widely used in business and emergency applications. Typically, these services use the UHF 2 band (450–470 MHz). In order to comply with continental practice, the provision of these services in the UK is to be realigned and a new operational assignment will be generated in 2005. However, this can only be achieved with an appropriate model and the ability to make assignments for large regional networks. The purpose of this paper is to bring our experiences of this problem to the wireless arena. We explain the model used when making assignments for UK PMR networks and identify existing techniques and theory which are appropriate for this problem. We demonstrate that improved assignments and estimates of spectral requirements for large operational services can be found.     

Compact Modules for Wireless Communication Systems in the E-Band (71–76 GHz)

The millimeter-wave spectrum above 70 GHz provides a cost-effective solution to increase the wireless communications data rates by increasing the carrier wave frequencies. We report on the development of two key components of a wireless transmission system, a high-speed photodiode (HS-PD) and a Schottky Barrier Diode (SBD). Both components operate uncooled, a key issue in the development of compact modules. On the transmitter side, an improved design of the HS-PD allows it to deliver an output RF power exceeding 0 dBm (1 mW). On the receiver side, we present the design process and achieved results on the development of a compact direct envelope detection receiver based on a quasi-optical SDB module. Different resonant (meander dipole) and broadband (Log-Spiral and Log-Periodic) planar antenna solutions are designed, matching the antenna and Schottky diode impedances at high frequency. Impedance matching at baseband is also provided by means of an impedance transition to a 50 Ohm output. From this comparison, we demonstrate the excellent performance of the broadband antennas over the entire E-band by setting up a short-range wireless link transmitting a 1 Gbps data signal.     

Efficient Non-Malleable Commitment Schemes

Non-malleability protects against man-in-the middle attacks on cryptographic protocols. Non-malleable commitment schemes, for example, assure that a commitment of a message does not help to produce a commitment of a related message. Here we present efficient constructions of such commitment schemes in the common reference string model based on standard assumptions such as RSA, factoring, or discrete logarithm. Our protocols require only three rounds and a few modular exponentiations, and provide statistical or even perfect secrecy of committed values.