Considering Transmission Impairments in Wavelength Routed Networks

Abstract — We consider dynamically reconfigurable wavelength routed networks in which lightpaths carrying IP traffic are on demand established. We face the Routing and Wavelength Assignment problem considering as constraints the physical impairments that arise in all-optical wavelength routed networks. In particular, we study the impact of the physical layer when establishing a lightpath in transparent optical network. Because no signal transformation and regeneration at intermediate nodes occurs, noise and signal distortions due to non-ideal transmission devices are accumulated along the physical path, and they degrade the quality of the received signal. We propose a simple yet accurate model for the physical layer which consider both static and dynamic impairments, i.e., nonlinear effects depending on the actual wavelength/lightpath allocation. We then propose a novel algorithm to solve the RWA problem that explicitly considers the physical impairments. Simulation results show the effectiveness of our approach. Indeed, when the transmission impairments come into play, an accurate selection of paths and wavelengths which is driven by physical consideration is mandatory. I

Increasing Accessibility of a Children\u27s Summer Camp

The Americans with Disabilities Act was initially passed in 1990 with an aim of creating accessible public spaces for all individuals with disabilities and impairments. Since that time, research on accessibility for children with physical impairments has largely been focused on access to homes and schools. It is clear that a lack of accessibility impacts children with physical impairments in other environments by reducing social participation and interaction with peers. There is minimal research on accessibility of children’s extracurricular spaces, such as summer camps, despite studies showing the importance of children with physical impairments participating in social extracurricular activities. This project assessed the ADA compliance and accessibility of a children’s summer camp with a focus on determining where accessibility could be improved to facilitate participation for all children

Off-line Survivable Impairment-aware Routing and Wavelength Assignment

Physical impairments caused by noise and signal distortions affect the quality of an optical signal. The effect of physical impairments becomes more significant with an increase in distance and bit rates. In order to minimize the bit error rate (BER), an optical signal may need to be regenerated after a certai

Compensation of Physical Impairments in Multi-Carrier Communications

Among various multi-carrier transmission techniques, orthogonal frequency-division multiplexing (OFDM) is currently a popular choice in many wireless communication systems. This is mainly due to its numerous advantages, including resistance to multi-path distortions by using the cyclic prefix (CP) and a simple one-tap channel equalization, and efficient implementations based on the fast Fourier and inverse Fourier transforms. However, OFDM also has disadvantages which limit its use in some applications. First, the high out-of-band (OOB) emission in OFDM due to the inherent rectangular shaping filters poses a challenge for opportunistic and dynamic spectrum access where multiple users are sharing a limited transmission bandwidth. Second, a strict orthogonal synchronization between sub-carriers makes OFDM less attractive in low-power communication systems. Furthermore, the use of the CP in OFDM reduces the spectral efficiency and thus it may not be suitable for short-packet and low-latency transmission applications. Generalized frequency division multiplexing (GFDM) and circular filter-bank multi-carrier offset quadrature amplitude modulation (CFBMC-OQAM) have recently been considered as alternatives to OFDM for the air interface of wireless communication systems because they can overcome certain disadvantages in OFDM. Specifically, these two systems offer a flexibility in choosing the shaping filters so that the high OOB emission in OFDM can be avoided. Moreover, the strict orthogonality requirement in OFDM is relaxed in GFDM and CFBMC-OQAM which are, respectively, non-orthogonal and real-field orthogonal systems. Although a CP is also used in these two systems, the CP is added for a block of many symbols instead of only one symbol as in OFDM, which, therefore, improves the spectral efficiency. Given that the performance of a wireless communication system is affected by various physical impairments such as phase noise (PN), in-phase and quadrature (IQ) imbalance and imperfect channel estimation, this thesis proposes a number of novel signal processing algorithms to compensate for physical impairments in multi-carrier communication systems, including OFDM, GFDM and CFBMC-OQAM. The first part of the thesis examines the use of OFDM in full-duplex (FD) communication under the presence of PN, IQ imbalance and nonlinearities. FD communication is a promising technique since it can potentially double the spectral efficiency of the conventional half-duplex (HD) technique. However, the main challenge in implementing an FD wireless device is to cope with the self-interference (SI) imposed by the device's own transmission. The implementation of SI cancellation (SIC) faces many technical issues due to the physical impairments. In this part of research, an iterative algorithm is proposed in which the SI cancellation and detection of the desired signal benefit from each other. Specifically, in each iteration, the SI cancellation performs a widely linear estimation of the SI channel and compensates for the physical impairments to improve the detection performance of the desired signal. The detected desired signal is in turn removed from the received signal to improve SI channel estimation and SI cancellation in the next iteration. Results obtained show that the proposed algorithm significantly outperforms existing algorithms in SI cancellation and detection of the desired signal. In the next part of the thesis, the impact of PN and its compensation for CFBMC-OQAM systems are considered. The sources of performance degradation are first quantified. Then, a two-stage PN compensation algorithm is proposed. In the first stage, the channel frequency response and PN are estimated based on the transmission of a preamble, which is designed to minimize the channel mean squared error (MSE). In the second stage the PN compensation is performed using the estimate obtained from the first stage together with the transmitted pilot symbols. Simulation results obtained under practical scenarios show that the proposed algorithm effectively estimates the channel frequency response and compensates for the PN. The proposed algorithm is also shown to outperform an existing algorithm that implements iterative PN compensation when the PN impact is high. As a further development from the second part, the third part of the thesis considers the impacts of both PN and IQ imbalance and proposes a unified two-stage compensation algorithm for a general multi-carrier system, which can include OFDM, GFDM and CFBMC-OQAM. Specifically, in the first stage, the channel impulse response and IQ imbalance parameters are first estimated based on the transmission of a preamble. Given the estimates obtained from the first stage, in the second stage the IQ imbalance and PN are compensated in that order based on the pilot symbols for the rest of data transmission blocks. The preamble is designed such that the estimation of IQ imbalance does not depend on the channel and PN estimation errors. The proposed algorithm is then further extended to a multiple-input multiple-output (MIMO) system. For such a MIMO system, the preamble design is generalized so that the multiple IQ imbalances as well as channel impulse responses can be effectively estimated based on a single preamble block. Simulation results are presented and discussed in a variety of scenarios to show the effectiveness of the proposed algorithm

Measurement of body temperature and heart rate for the development of healthcare system using IOT platform

Health can be define as a state of complete mental, physical and social well-being and not merely the absence of disease or infirmity according to the World Health Organization (WHO) [1]. Having a healthy body is the greatest blessing of life, hence healthcare is required to maintain or improve the health since the healthcare is the maintenance or improvement of health through the diagnosis, prevention, and treatment of injury, disease, illness, and other mental and physical impairments in human beings. The novel paradigm of Internet of Things (IoT) has the potential to transform modern healthcare and improve the well-being of entire society [2]. IoT is a concept aims to connec

Role-Taking vs. cultural identity: Defining disability in an able-bodied environment

Are people with physical impairments seen as a minority group or as individuals who take on the role of being disabled only in certain circumstances? While minority group membership has a variety of social, psychological, and legal advantages, it forces people to give up some individuality and gives the disability a more permanent connotation (Berbrier, 2004; Watson, 2002). Alternately, viewing disability as a role, and attaching the label disabled in certain circumstances, allows for a broader spectrum of individual choice. However, the label assumes someone who is disabled to be less than able, thus carrying a strong stigma. Through my personal experience with a temporary disability, I examined the labels placed on people with physical impairments, both by the individual and by society in general. I conclude that the lived experiences of those with disabilities do not demonstrate that people with physical impairments self-identify as a member of the disabled community, but that they take on this label only when the environment fails to meet their needs

Fragmentary worlds: Unnatural perceptions of and responses to severe weather by people with sensory/mobility impairments.

This study is the first to investigate how people with disabilities perceive and respond to severe weather alerts. Their unfortunate experiences, underscored by the Indian Ocean monster tsunami in 2004 and hurricane Katrina in 2005 reinforced the need to further understand the manner in which people with sensory/physical impairments perceive and respond to severe weather warnings. In this dissertation I argue that people with sensory/physical impairments often demonstrate an unnatural quality to 'natural' hazards in their approach and behavior to severe weather. In order to achieve this objective I use a methodology first developed and implemented by Zimmerman and Wieder (1977), the Diary: Diary-Interview Method, to examine these unnatural personal experiences of 5 research subjects with diverse sensory and physical impairments, between the ages of 24 and 60, during the Spring and Summer months of 2005 and 2006. These experiences are then compared to the experiences of a able-bodied control group. Analysis of the data reveals that a lack of social capital suggests an unnatural hazards component when severe weather events threaten. However, participants with access to social capital exhibit a commonalty with able-bodied participants and demonstrate natural circumstances when dealing with severe weather events. Following this evidence, I conclude from the results of the research that social capital is a necessity for people with sensory and/or physical impairments, and this evidence should be accounted for when considering the theory of unnatural hazards.Key words: people with sensory/physical disabilities, natural/unnatural hazards, personal experiences

Use of an agile bridge in the development of assistive technology

Engaging with end users in the development of assistive technologies remains one of the major challenges for researchers and developers in the field of accessibility and HCI. Developing usable software systems for people with complex disabilities is problematic, software developers are wary of using user-centred design, one of the main methods by which usability can be improved, due to concerns about how best to work with adults with complex disabilities, in particular Severe Speech and Physical Impairments (SSPI) and how to involve them in research. This paper reports on how the adoption of an adapted agile approach involving the incorporation of a user advocate on the research team helped in meeting this challenge in one software project and offers suggestions for how this could be used by other development teams

A Novel Solution to the Dynamic Routing and Wavelength Assignment Problem in Transparent Optical Networks

We present an evolutionary programming algorithm for solving the dynamic routing and wavelength assignment (DRWA) problem in optical wavelength-division multiplexing (WDM) networks under wavelength continuity constraint. We assume an ideal physical channel and therefore neglect the blocking of connection requests due to the physical impairments. The problem formulation includes suitable constraints that enable the algorithm to balance the load among the individuals and thus results in a lower blocking probability and lower mean execution time than the existing bio-inspired algorithms available in the literature for the DRWA problems. Three types of wavelength assignment techniques, such as First fit, Random, and Round Robin wavelength assignment techniques have been investigated here. The ability to guarantee both low blocking probability without any wavelength converters and small delay makes the improved algorithm very attractive for current optical switching networks.Comment: 12 Pages, IJCNC Journal 201

Kinematic evaluation of physical impairments of an elite Paralympic karateka

Karate is a Japanese martial art that counts millions of practitioners worldwide and that is spreading also in Paralympic competitions, requiring accurate categories definition for disabled athletes. The aim of the study is to present kinematic data of an elite Paralympic karateka, in comparison with able-bodied athletes. The authors also aim to promote a better classification within the discipline, based on objective biomechanical evaluations of physical impairments. A male black belt Paralympic karateka (age: 36 y; body weight: 75.5 kg; height: 173 cm) with lower limbs impairments was evaluated. The athlete had been performing high level karate for 20 years before the disability took place. After the post-operative rehabilitation, he attended 3/4 sessions of para- karate training per week. He performed a standardized sequence of movements, involving a sequence of offensive and defensive techniques, (kata) from traditional Shotokan karate. Joints and body Center of Mass (CoM) kinematics were collected with an optoelectronic motion capture system and compared with those obtained in two groups of able-bodied (elite and amateurs) athletes from a previous study1. Knee angular range of motion (RoM) and peak angular velocity were obtained. Coordinates of CoM were estimated, using the Segmental Centroid Method2, along with CoM average velocity and acceleration. To assess differences between Paralympic karateka and able-bodied groups, the one-sample t-test was performed. The sequence performed by the karateka lasted more than in both able-bodied groups. CoM average velocity and acceleration decreased in comparison with elite karateka. Knees range of movement and peak angular velocity were similar to amateur but lower than elite athletes. Results show that the physical impairments negatively affected the function of lower limbs in the Paralympic athlete. Fundamental skills in karate elite performance (dynamic balance control and joint RoM and angular velocity) were reduced