Source-Channel Coding under Energy, Delay and Buffer Constraints

Source-channel coding for an energy limited wireless sensor node is investigated. The sensor node observes independent Gaussian source samples with variances changing over time slots and transmits to a destination over a flat fading channel. The fading is constant during each time slot. The compressed samples are stored in a finite size data buffer and need to be delivered in at most $d$ time slots. The objective is to design optimal transmission policies, namely, optimal power and distortion allocation, over the time slots such that the average distortion at destination is minimized. In particular, optimal transmission policies with various energy constraints are studied. First, a battery operated system in which sensor node has a finite amount of energy at the beginning of transmission is investigated. Then, the impact of energy harvesting, energy cost of processing and sampling are considered. For each energy constraint, a convex optimization problem is formulated, and the properties of optimal transmission policies are identified. For the strict delay case, $d=1$, $2D$ waterfilling interpretation is provided. Numerical results are presented to illustrate the structure of the optimal transmission policy, to analyze the effect of delay constraints, data buffer size, energy harvesting, processing and sampling costs.Comment: 30 pages, 15 figures. Submitted to IEEE Transactions on Wireless Communication

Energy Harvesting Broadband Communication Systems with Processing Energy Cost

Communication over a broadband fading channel powered by an energy harvesting transmitter is studied. Assuming non-causal knowledge of energy/data arrivals and channel gains, optimal transmission schemes are identified by taking into account the energy cost of the processing circuitry as well as the transmission energy. A constant processing cost for each active sub-channel is assumed. Three different system objectives are considered: i) throughput maximization, in which the total amount of transmitted data by a deadline is maximized for a backlogged transmitter with a finite capacity battery; ii) energy maximization, in which the remaining energy in an infinite capacity battery by a deadline is maximized such that all the arriving data packets are delivered; iii) transmission completion time minimization, in which the delivery time of all the arriving data packets is minimized assuming infinite size battery. For each objective, a convex optimization problem is formulated, the properties of the optimal transmission policies are identified, and an algorithm which computes an optimal transmission policy is proposed. Finally, based on the insights gained from the offline optimizations, low-complexity online algorithms performing close to the optimal dynamic programming solution for the throughput and energy maximization problems are developed under the assumption that the energy/data arrivals and channel states are known causally at the transmitter.Comment: published in IEEE Transactions on Wireless Communication

Coupled flow and contaminant transport modeling in large watersheds

A hybrid surface/subsurface flow and transport model is developed that blends distributed parameter models with simpler lumped parameter models. The hybrid model solves the channel flow and saturated groundwater flow domains in continuous time using fully distributed physically-based formulations. This system is supplemented with the overland flow and unsaturated groundwater flow that uses lumped parameter descriptions in discrete time. In the proposed model, a one-dimensional channel flow model is dynamically coupled with a two-dimensional vertically-averaged groundwater flow model along the river bed. As an alternative to the commonly applied iterative solution technique, a so-called simultaneous solution procedure is developed to provide a better understanding to the coupled flow problem. This new methodology is based on the principle of solving the two flow domains within a single matrix structure in a simultaneous manner. In addition to the flow model, a coupled contaminant transport model is also developed to simulate the migration of contaminants between surface and subsurface domains. The contaminant transport model dynamically couples a one-dimensional channel transport model with a two-dimensional vertically-averaged groundwater transport model. The coupling is performed at the river bed interface via advective and dispersive transport mechanisms. A modified extension of the proposed simultaneous solution procedure is also implemented to solve the coupled contaminant transport problem. The dynamic coupling provides the much needed understanding for the continuity of contaminants in strongly interacting surface/subsurface systems such as a river and an unconfined aquifer. The coupled flow and transport models are applied to the lower Altamaha watershed in southern Georgia. The flow model is used to perform simulations of hydrologic and hydraulic conditions along the river and in the dynamically linked surfacial aquifer. The model predicted the flood patterns including the magnitude of peaks and their arrival times with accuracy. Under the given flow conditions, the transport model is then implemented to test alternative contaminant transport patterns both in the river and within the aquifer. It has been found that the channel network would serve as a conduit for rapid transport of contaminants within the aquifer to large distances in small time frames.Ph.D.Committee Chair: Dr. Mustafa Aral; Committee Member: Dr. Paul Work; Committee Member: Dr. Philip Roberts; Committee Member: Dr. Terry Sturm; Committee Member: Dr. Turgay Uze

Detaljna procjena "koronoidnih foramena" i pomoćnih foramena mandibule pomoću CBCT: jedinstvena anatomska varijacija

The aim of the study was to evaluate accessory foramina (AF) located on the medial aspect and to present a unique finding of ‘coronoid foramina’ (CF) along with AF on the mandible. The cone beam computed tomography images of the mandible in 979 patients were retrospectively evaluated for the presence of CF and AF. AF was found in 39 (3.98%) patients. AF located on the medial surface below and above mandibular foramen was found in 15.38% and 84.62% of patients, respectively. CF was confirmed in 20 (2.04%) patients. Mandibular AF is important for surgical procedures in the posterior region of the mandible and for mandibular nerve anesthesia. This study including CF will be useful for further studies due to the lack of literature on the issue.Cilj istraživanja bio je procijeniti pomoćne foramene (PF) smještene na medijalnom dijelu i prikazati jedinstven nalaz ‘koronoidnih foramena’ (KF) uz PF na mandibuli. Snimke mandibule u 979 pacijenata dobivene tehnikom CBCT (cone beam computed tomography) retrospektivno su procijenjene na prisutnost PF i KF. PF je nađen u 39 (3,98%) pacijenata. PF smješten na medijalnoj površini ispod i iznad mandibularnog foramena uvrđen je u 15,38% odnosno 84,62% pacijenata. KF je potvrđen u 20 (2,04%) pacijenata. Mandibularni PF je važan za kirurške zahvate u stražnjem dijelu mandibule, kao i za anesteziju mandibularnog živca. Zbog nedostatka literature o ovom pitanju, ovo istraživanje koje je obuhvatilo KF bit će korisno za buduće istraživanje u ovom području

Anatomija i mjerne vrijednosti Rosenmüllerove jame i struktura orofarinksa pomoću cone beam kompjutorizirane tomografije

The objective of this study was to assess Rosenmüller fossa (RF) anatomy and neighboring structures using cone beam computed tomography (CBCT). A total of 1000 patients were analyzed using CBCT. The reference points were based on the spina nasalis posterior (Snp) and basion. The length between RF and neighboring structures were measured.The mean distance from Snp to the posterior pharyngeal wall was 17.7 mm. The mean distance from right to left torus levatorius was 25.69 mm. The mean depth of right RF was 5.54 mm while the mean depth of left RF was 5.26 mm. RF, also described as the lateral pharyngeal recess, is a source location of nasopharyngeal carcinoma development. Its location is on the lateral pharyngeal wall posterior to the cartilaginous part of the eustachian tube, the torus tubarius. The knowledge of RF is important to diagnose and perform treatment planning of nasopharyngeal carcinoma.Cilj istraživanja bio je procijeniti anatomiju Rosenmüllerove jame (RJ) i okolnih struktura pomoću cone beam kompjutorizirane tomografije (CBCT). Ukupno je 1000 bolesnika analizirano ovom tehnikom. Referentne točke bile su spina nasalis posterior (Snp) i basion. Mjerena je duljina između RJ i okolnih struktura. Srednja udaljenost od Snp do stražnje faringealne stijenke bila je 17,7 mm. Srednja udaljenost od desnog do lijevog torusa levatoriusa bila je 25,69 mm. Srednja dubina desne i lijeve RJ bila je 5,54 mm odnosno 5,26 mm. RJ, poznata i kao lateralno udubljenje farinksa, izvorno je mjesto za razvoj nazofaringealnog karcinoma. Smještena je na lateralnoj stijenci farinksa iza hrskavičnog dijela eustahijeve cijevi, tj. torus tubarius. Poznavanje RJ važno je za dijagnosticiranje i planiranje liječenja nazofaringealnog karcinoma

Anatomija i mjerne vrijednosti Rosenmüllerove jame i struktura orofarinksa pomoću cone beam kompjutorizirane tomografije

The objective of this study was to assess Rosenmüller fossa (RF) anatomy and neighboring structures using cone beam computed tomography (CBCT). A total of 1000 patients were analyzed using CBCT. The reference points were based on the spina nasalis posterior (Snp) and basion. The length between RF and neighboring structures were measured.The mean distance from Snp to the posterior pharyngeal wall was 17.7 mm. The mean distance from right to left torus levatorius was 25.69 mm. The mean depth of right RF was 5.54 mm while the mean depth of left RF was 5.26 mm. RF, also described as the lateral pharyngeal recess, is a source location of nasopharyngeal carcinoma development. Its location is on the lateral pharyngeal wall posterior to the cartilaginous part of the eustachian tube, the torus tubarius. The knowledge of RF is important to diagnose and perform treatment planning of nasopharyngeal carcinoma.Cilj istraživanja bio je procijeniti anatomiju Rosenmüllerove jame (RJ) i okolnih struktura pomoću cone beam kompjutorizirane tomografije (CBCT). Ukupno je 1000 bolesnika analizirano ovom tehnikom. Referentne točke bile su spina nasalis posterior (Snp) i basion. Mjerena je duljina između RJ i okolnih struktura. Srednja udaljenost od Snp do stražnje faringealne stijenke bila je 17,7 mm. Srednja udaljenost od desnog do lijevog torusa levatoriusa bila je 25,69 mm. Srednja dubina desne i lijeve RJ bila je 5,54 mm odnosno 5,26 mm. RJ, poznata i kao lateralno udubljenje farinksa, izvorno je mjesto za razvoj nazofaringealnog karcinoma. Smještena je na lateralnoj stijenci farinksa iza hrskavičnog dijela eustahijeve cijevi, tj. torus tubarius. Poznavanje RJ važno je za dijagnosticiranje i planiranje liječenja nazofaringealnog karcinoma

Changes in Serum Natriuretic Peptide Levels after Percutaneous Closure of Small to Moderate Ventricular Septal Defects

Background. B-type natriuretic peptide has been shown to be a very sensitive and specific marker of heart failure. In this study, we aimed to investigate the effect of percutaneous closure of ventricular septal defects with Amplatzer septal occluders on brain natriuretic peptide levels. Methods. Between 2008 and 2011, 23 patients underwent successfully percutaneous ventricular septal defect closure in 4 cardiology centers. Brain natriuretic peptide levels were measured in nine patients (4 male, mean ages were 25.3 ± 14.3) who underwent percutaneous closure with Amplatzer occluders for membranous or muscular ventricular septal defects were enrolled in the study. Brain natriuretic peptide levels were measured one day before and one month after the closure. Patients were evaluated clinically and by echocardiography one month after the procedure. Results. Percutaneous closures of ventricular septal defects were successfully performed in all patients. There was not any significant adverse event in patients group during followup. Decrease in brain natriuretic peptide levels after closure were statistically significant (97.3 ± 78.6 versus 26.8 ± 15.6, P = 0.013). Conclusion. Brain Natriuretic Peptide levels are elevated in patients with ventricular septal defects as compared to controls. Percutaneous closure of Ventricular Septal Defect with Amplatzer occluders decreases the BNP levels

Water Quality Perspectives in a Changing World

Water is a crucial part of human life. Ever-increasing population coupled with changing life styles is constantly increasing the demand for water. Today, populations require more water with higher quality standards than before, and it is becoming more difficult to satisfy these demands without altering the balance of nature. Anthropogenic stresses and natural phenomenon are playing critical roles during the supply of sufficient quantities of water with required quality. Consequently, previously unused resources are being considered for use; advanced treatment methods are being implemented to satisfy the quality requirements, and reuse of wastewaters is becoming a significant factor in many parts of the world. While trying to satisfy this supply-demand cycle, resource managers and decision makers are facing other challenges, which, in essence, are re-defining our whole understanding for water resources management. Health concerns related to water quality are being the primary issue all around the world, and the direction of research is now shifting towards understanding the complex interactions that water quality imposes on human health