In this thesis, the problem of quantifying the Pareto optimal boundary of the achievable rate region is considered over multiple-input single-output(MISO)interference channels, where the problem boils down to solving a sequence of convex feasibility problems after certain transformations. The feasibility problem is solved by two new distributed optimal beam forming algorithms, where the first one is to parallelize the computation based on the method of alternating projections, and the second one is to localize the computation based on the method of cyclic projections. Convergence proofs are established for both algorithms.

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The cognitive radio (CR) concept is expected to be adopted along with many technologies to meet the requirements of the next generation of wireless and mobile systems, the 5G. Consequently, it is important to determine the performance of the CR systems with respect to these requirements. In this thesis, after briefly describing the 5G requirements, we present three main directions in which we aim to enhance the CR performance. The first direction is the reliability. We study the achievable rate of a multiple-input multiple-output (MIMO) relay-assisted CR under two scenarios; an unmanned aerial vehicle (UAV) one-way relaying (OWR) and a fixed two-way relaying (TWR). We propose special linear precoding schemes that enable the secondary user (SU) to take advantage of the primary-free channel eigenmodes. We study the SU rate sensitivity to the relay power, the relay gain, the UAV altitude, the number of antennas and the line of sight availability. The second direction is the scalability. We first study a multiple access channel (MAC) with multiple SUs scenario. We propose a particular linear precoding and SUs selection scheme maximizing their sum-rate. We show that the proposed scheme provides a significant sum-rate improvement as the number of SUs increases. Secondly, we expand our scalability study to cognitive cellular networks. We propose a low-complexity algorithm for base station activation/deactivation and dynamic spectrum management maximizing the profits of primary and secondary networks subject to green constraints. We show that our proposed algorithms achieve performance close to those obtained with the exhaustive search method. The third direction is the energy efficiency (EE). We present a novel power allocation scheme based on maximizing the EE of both single-input and single-output (SISO) and MIMO systems. We solve a non-convex problem and derive explicit expressions of the corresponding optimal power. When the instantaneous channel is not available, we present a simple sub-optimal power that achieves a near-optimal EE. The simulations show that the sub-optimal solution is very close to the optimal one. In the MIMO case, we show that adopting more antennas is more energy efficient.

The capacity of multiuser wireless network, unclear for many years, has always been a hot research topic. Many different operation schemes and coding techniques have been proposed to enlarge the achievable rate region. And omnidirectional relay scheme is one of them. This thesis mainly works on the achievable region of the all-source all-cast network with omnidirectional relay scheme. In order to better understand this problem, we first describe the half-duplex model on the one-dimensional and two-dimensional regular networks. And we present an optimal operation scheme for them to have the maximum achievable rate. For the one-dimensional general network, we proposed an achievable region that indicates valued improvement compared to the previous results. In the full-duplex model of the one-dimensional general network, the maximum achievable rate is presented with a simpler proof in comparison with the previous results. In this thesis, we also show some discussions on more general networks.

The capacity of multiuser wireless network, unclear for many years, has always been a hot research topic. Many different operation schemes and coding techniques have been proposed to enlarge the achievable rate region. And omnidirectional relay scheme is one of them. This thesis mainly works on the achievable region of the all-source all-cast network with omnidirectional relay scheme. In order to better understand this problem, we first describe the half-duplex model on the one-dimensional and two-dimensional regular networks. And we present an optimal operation scheme for them to have the maximum achievable rate. For the one-dimensional general network, we proposed an achievable region that indicates valued improvement compared to the previous results. In the full-duplex model of the one-dimensional general network, the maximum achievable rate is presented with a simpler proof in comparison with the previous results. In this thesis, we also show some discussions on more general networks.

No description available.

Human health risk assessments are used by environmental regulatory agencies to determine risk from Hazardous Air Pollutants (HAPs). In this study, the Human Exposure Model (HEM-3) was used to compare the cancer and non-cancer inhalation health effects of a single organic chemical manufacturing facility in Geismar, Louisiana prior to and after Maximum Achievable Control Technologies (MACT) were implemented. The results indicate significant reductions in both cancer risk and non-cancer hazards. The analysis also indicated that the equivalent cancer risk reduction could have been achieved by addressing MACT in only one production process and one single pollutant (ethylene dichloride) within that process. This demonstrates the value that these risk assessments have at evaluating emissions at the facility level, and how they could be used in the control strategy decision making process.

abstract: Cognitive radio (CR) and device-to-device (D2D) systems are two promising dynamic spectrum access schemes in wireless communication systems to provide improved quality-of-service, and efficient spectrum utilization. This dissertation shows that both CR and D2D systems benefit from properly designed cooperation scheme. In underlay CR systems, where secondary users (SUs) transmit simultaneously with primary users (PUs), reliable communication is by all means guaranteed for PUs, which likely deteriorates SUs’ performance. To overcome this issue, cooperation exclusively among SUs is achieved through multi-user diversity (MUD), where each SU is subject to an instantaneous interference constraint at the primary receiver. Therefore, the active number of SUs satisfying this constraint is random. Under different user distributions with the same mean number of SUs, the stochastic ordering of SU performance metrics including bit error rate (BER), outage probability, and ergodic capacity are made possible even without observing closed form expressions. Furthermore, a cooperation is assumed between primary and secondary networks, where those SUs exceeding the interference constraint facilitate PU’s transmission by relaying its signal. A fundamental performance trade-off between primary and secondary networks is observed, and it is illustrated that the proposed scheme outperforms non-cooperative underlay CR systems in the sense of system overall BER and sum achievable rate. Similar to conventional cellular networks, CR systems suffer from an overloaded receiver having to manage signals from a large number of users. To address this issue, D2D communications has been proposed, where direct transmission links are established between users in close proximity to offload the system traffic. Several new cooperative spectrum access policies are proposed allowing coexistence of multiple D2D pairs in order to improve the spectral efficiency. Despite the additional interference, it is shown that both the cellular user’s (CU) and the individual D2D user's achievable rates can be improved simultaneously when the number of D2D pairs is below a certain threshold, resulting in a significant multiplexing gain in the sense of D2D sum rate. This threshold is quantified for different policies using second order approximations for the average achievable rates for both the CU and the individual D2D user. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2017

Nanoscale communication is appealing domain in nanotechnology. There are many existing nanoscale communication methods. In addition to these, novel techniques can be derived depending on the naturally existing phenomena such as molecular communication. It uses molecules as an information carrier such as molecular motors, pheromones and neurotransmitters for neuro-spike communication. Among them, neuro-spike communication is a vastly unexplored area. The ultimate goal of this thesis is to accurately investigate it by obtaining a realistic physical channel model. This model can be exploited in different disciplines. Furthermore, the model can help designing novel artificial nanoscale communication paradigms. The modeled channel is analyzed regarding the error probability of detecting spikes depending on channel parameters. Moreover, channel delay is characterized and information theoretical analysis of packet release mechanism in the channel is performed. The modeled channel is extended to multi-input single output terminal. In this case, input neurons can simultaneously send information through the same synapse leading to interference. However, there is an interference repressing technique in these synapses called automatic gain control. It decreases the interference level observed on weaker signal. The first aim for this case is to define the interference channel at synapse having automatic gain control. The second aim is to analyze the achievable rate region of this channel. The analysis shows that gain control mechanism prevents the decrease in achievable rate region because of the weaker signal. Moreover, power, firing rate and number of stronger inputs do not affect the achievable rate region.

Background: Jet injectors are advantageous over needle injectors by eliminating sharps hazards. The Government Accountability Office estimates 29% preventable sharp injuries with an estimated direct cost of more than $500 million out of the CDC's reported incidence of 385,000 needle stick injuries per year among US hospital healthcare workers. Yet the forces required to set and trigger devices using spring mechanisms for medication delivery have not been explored. This laboratory experiment measured forces exerted by healthcare workers (HCWs) using a particular jet injector approved by FDA in 2011. Objectives: In order to quantify the ergonomic impact on HCWs using a needle-free injector, the first objective was to evaluate the dynamic forces required to activate the trigger injector button and the reset station for the injector, with their respective means, for each of the parameters studied. The second objective was to compare these forces to those required to use four previously analyzed retractable intramuscular syringes with needles. Finally, the third objective was to assess potential psychophysics ergonomic impact on HCWs with use of these devices to formulate future design changes and recommendations for manufacturers and HCWs, respectively. Methods: This laboratory experiment was conducted through a multi-disciplinary team approach. It included a total of 136 trials (10 validation trials, 116 experimental trials and 10 padded trials for soft tissue simulation), which were conducted using the PharmaJetTM Injector. A force gauge and a load cell were integrated into the triggering setup and reset station, correspondingly, enabling force measurements to be obtained directly from the human-machine interfaces. These force data allowed for observations of force profiles in time by the healthcare worker as researcher while preparing for and administering injections. Data collection used three software applications for force conversions and data manipulation. Data were analyzed using descriptive statistics and analytical results by using ANOVA for the trigger injector & reset station with multiple comparison tests for parametric and non-parametric distributions, respectively. Results: The descriptive results indicated an average force for triggering the injector in the 116 trials was 15.92 lbs. (70.8 N) with a range of 9.77-26.46 lbs. (43.46-117.69 N). The measured forces for the reset station ranged from 5.35-82.78 lbs. (5.35-368.22 N) with an average of 25.32 lbs. (112.62 N) (SD 12.36). Spurious findings presented with tensile forces to fill the syringes resulting in hand strain in the first metacarpal joint after repetitive pinprick motion. The analytical results showed an ANOVA for trigger injector with a parametric-normal distribution with an F (2,133) Ratio 10.0472, p- value (F) 0.0001<0.05, showing statistical significance and with a Tukey's comparison test showing a significant difference in between the means of the padded trials vs. the validation & experimental trial groups. The ANOVA for the reset station showed a Kruskal Wallis H-statistic of 0.2568, p-value (H) 0.8795>0.05 presenting NO statistical significance with a Dunn's comparison test confirming NO difference in between the medians or mean ranks of all three groups. Conclusions: Triggering the injector and resetting the station required considerable effort in comparison to activating 4 retractable intramuscular syringes with needles from our previous studies, the range of mean forces were 3.63-17 lbs (16.19-77.53 N) for those syringes with the trigger injector maximum voluntary force of 71 N being above the recommend 56.6 N.The jet injector required more force per effort than 2 (4.4x) syringes & similar to other 2 syringes (0.9x) previously tested when considering the compression forces related with the trigger injector. Additional vector forces (displacement & gripping of reset station) could increase the cumulative effort affecting different musculoskeletal components when the whole components of the procedure are taken into account. Suggestions for the manufacturer regarding design changes to facilitate HCWs' use of this device are warranted, since some of the summation forces during the 12 mini-steps could be avoided to achieve a higher efficiency. This information may be useful for health care facilities when choosing devices to protect their workers from ergonomic injuries.