Scheduling with Rate Adaptation under Incomplete Knowledge of Channel/Estimator Statistics

In time-varying wireless networks, the states of the communication channels are subject to random variations, and hence need to be estimated for efficient rate adaptation and scheduling. The estimation mechanism possesses inaccuracies that need to be tackled in a probabilistic framework. In this work, we study scheduling with rate adaptation in single-hop queueing networks under two levels of channel uncertainty: when the channel estimates are inaccurate but complete knowledge of the channel/estimator joint statistics is available at the scheduler; and when the knowledge of the joint statistics is incomplete. In the former case, we characterize the network stability region and show that a maximum-weight type scheduling policy is throughput-optimal. In the latter case, we propose a joint channel statistics learning - scheduling policy. With an associated trade-off in average packet delay and convergence time, the proposed policy has a stability region arbitrarily close to the stability region of the network under full knowledge of channel/estimator joint statistics.Comment: 48th Allerton Conference on Communication, Control, and Computing, Monticello, IL, Sept. 201

Multiuser Scheduling in a Markov-modeled Downlink using Randomly Delayed ARQ Feedback

We focus on the downlink of a cellular system, which corresponds to the bulk of the data transfer in such wireless systems. We address the problem of opportunistic multiuser scheduling under imperfect channel state information, by exploiting the memory inherent in the channel. In our setting, the channel between the base station and each user is modeled by a two-state Markov chain and the scheduled user sends back an ARQ feedback signal that arrives at the scheduler with a random delay that is i.i.d across users and time. The scheduler indirectly estimates the channel via accumulated delayed-ARQ feedback and uses this information to make scheduling decisions. We formulate a throughput maximization problem as a partially observable Markov decision process (POMDP). For the case of two users in the system, we show that a greedy policy is sum throughput optimal for any distribution on the ARQ feedback delay. For the case of more than two users, we prove that the greedy policy is suboptimal and demonstrate, via numerical studies, that it has near optimal performance. We show that the greedy policy can be implemented by a simple algorithm that does not require the statistics of the underlying Markov channel or the ARQ feedback delay, thus making it robust against errors in system parameter estimation. Establishing an equivalence between the two-user system and a genie-aided system, we obtain a simple closed form expression for the sum capacity of the Markov-modeled downlink. We further derive inner and outer bounds on the capacity region of the Markov-modeled downlink and tighten these bounds for special cases of the system parameters.Comment: Contains 22 pages, 6 figures and 8 tables; revised version including additional analytical and numerical results; work submitted, Feb 2010, to IEEE Transactions on Information Theory, revised April 2011; authors can be reached at [email protected]/[email protected]/[email protected]

Thermal optical non-linearity of nematic mesophase enhanced by gold nanoparticles – an experimental and numerical investigation

In this work the mechanisms leading to the enhancement of optical nonlinearity of nematic liquid crystalline material through localized heating by doping the liquid crystals (LCs) with gold nanoparticles (GNPs) are investigated. We present some experimental and theoretical results on the effect of voltage and nanoparticle concentration on the nonlinear response of GNP-LC suspensions. The optical nonlinearity of these systems is characterized by diffraction measurements and the second order nonlinear refractive index, n 2 , is used to compare systems with different configurations and operating conditions. A theoretical model based on heat diffusion that takes into account the intensity and finite size of the incident beam, the nanoparticle concentration dependent absorbance of GNP doped LC systems and the presence of bounding substrates is developed and validated. We use the model to discuss the possibilities of further enhancing the optical nonlinearity

Canonical horizontal visibility graphs are uniquely determined by their degree sequence

Horizontal visibility graphs (HVGs) are graphs constructed in correspondence with number sequences that have been introduced and explored recently in the context of graph-theoretical time series analysis. In most of the cases simple measures based on the degree sequence (or functionals of these such as entropies over degree and joint degree distributions) appear to be highly informative features for automatic classification and provide nontrivial information on the associated dynam- ical process, working even better than more sophisticated topological metrics. It is thus an open question why these seemingly simple measures capture so much information. Here we prove that, under suitable conditions, there exist a bijection between the adjacency matrix of an HVG and its degree sequence, and we give an explicit construction of such bijection. As a consequence, under these conditions HVGs are unigraphs and the degree sequence fully encapsulates all the information of these graphs, thereby giving a plausible reason for its apparently unreasonable effectiveness

Zastosowanie kliniczne świeżo mrożonego osocza w szpitalu referencyjnym w Indiach

Background. Increased utilization of fresh frozen plasma (FFP) over the last decade hascaused a rising trend in its unjustified usage exposing recipients to both infectious and non--infectious hazards. The aim of the study was to observe the pattern of clinical use of plasmaat a tertiary care hospital from India.Material and methods. Prospective analysis of all the requests raised for plasma was carriedout. Indicators namely homogeneity of the requisition forms, patient demographics, indicationsfor transfusion, dosage, pre-transfusion coagulation parameters and adverse events werenoted. Appropriateness was defined based on compliance to both national and internationalstandards. Data was analyzed using SPSS version 20 (IBM, USA).Results. Total nine hundred ninety eight patients (Males: 66%) received 4991 units ofplasma at an average of two episodes per patient. Majority were adults 83.6% (n = 835).Primary users were internal medicine (32%) and plastic surgery (17%) respectively. Mostcommon indication was bleeding with coagulopathy seen in 41% (411/998) patients. Averageplasma volume administered was 456.2 ± 287.4 (17 to 2800) mL per episode. Pre--transfusions INR value was available in only 63.2% (n = 1317) episodes. Overall, 56% (n= 1169) episodes were deemed appropriate. Total 0.28% plasma related adverse reactionswere seen and reported to the national hemovigilance database. Mortality in the study groupwas 7.2%.Conclusion. Existing transfusion practices for plasma use were moderately compliant withthe standards. Commonest indications for inappropriate FFP use were for low protein statesand prophylaxis without any evidence of bleeding.Wstęp. W ciągu ostatniej dekady znacznie zwiększyło się zużycie świeżo mrożonego osocza(fresh frozen plasma, FFP), co spowodowało rosnącą tendencję do nieuzasadnionego stosowaniaFFP, a tym samym narażenie pacjentów na ryzyko związane z zakażeniami i niezakaźnymi powikłaniami. Badanie przeprowadzono w celu zaobserwowania, w jaki sposób stosuje sięFFP w referencyjnym szpitalu w Indiach.Materiał i metody. Przeanalizowano w sposób prospektywny wszystkie przypadki zamówieńosocza. Stosowano jednorodne formularze zamówienia i odnotowano dane demograficznechorych, wskazania do transfuzji, dawkę, parametry krzepliwości krwi przed transfuzją orazzdarzenia niepożądane. Prawidłowe stosowanie definiowano jako zgodność z krajowymi i międzynarodowymistandardami. Do analizy danych użyto oprogramowania SPSS, wersja 20(IBM, Stany Zjednoczone).Wyniki. Ogółem 998 chorym (66% mężczyzn) podano 4991 jednostek osocza, a średnia liczbatransfuzji na pacjenta wynosiła 2. Większość stanowiły osoby dorosłe (83.6%; n = 835).Największą grupę stanowili pacjenci internistyczni (32%) i osoby poddające się zabiegom z zakresuchirurgii plastycznej (17%). Najczęstszym wskazaniem było krwawienie z koagulopatiąobserwowane u 41% (411/998) chorych. Średnia objętość podanego osocza wynosiła 456,2± 287,4 (17 do 2800) ml na transfuzję. Wartość INR przed transfuzją była dostępna tylkow 63,2% (n = 1317) epizodów. Ogółem, 56% (n = 1169) epizodów uznano za prawidłowe.W 0,28% przypadków zaobserwowano działania niepożądane i zgłoszono je do krajowej bazynadzoru hematologicznego. Odnotowano 72 przypadki zgonów (7,2% chorych).Wnioski. Stosowana praktyka dotycząca transfuzji osocza była umiarkowanie zgodna ze standardami.Najczęściej stwierdzanymi nieprawidłowościami było stosowanie FFP w przypadkuniedoborów białkowych i w ramach profilaktyki przy braku jakichkolwiek oznak krwawienia

Atmospheric cold plasma: A novel technique for microbial inactivation and quality preservation of spices and herbs

The global production of spices and herbs has increased significantly in recent decades due to growing consumer demand. However, this expansion has been accompanied by a rise in foodborne illness outbreaks associated with these products, necessitating advancements in processing methods. Atmospheric cold plasma (ACP) has emerged as a promising food treatment technique for improving product safety and extending shelf life. This paper reviews the application of ACP in spices and herbs processing, focusing on its microbial inactivation capabilities and its effects on nutritional and physico-chemical properties. While research generally supports the effectiveness of ACP, its impact varies significantly based on treatment parameters and the specific spice or herb being processed. Comprehending these variations is critical for optimizing ACP conditions to ensure the safety and quality of the final products. Further research is required to refine ACP applications tailored to different spices and herbs, providing deeper insight into its potential. The findings underscore the importance of customized processing strategies that meet safety standards while preserving the natural qualities of spices and herbs, catering to an increasingly health-conscious market. Additionally, the scalability of ACP technology for industrial applications remains an area of active investigation, as larger-scale processing introduces unique challenges. Addressing these challenges will be critical for the widespread adoption of ACP in the spice and herb industry, ensuring consistent outcomes across diverse production environments

Examining Wildfire Dynamics Using ECOSTRESS Data with Machine Learning Approaches: The Case of South-Eastern Australia\u27s Black Summer

Wildfires are increasing in risk and prevalence. The most destructive wildfires in decades in Australia occurred in 2019–2020. However, there is still a challenge in developing effective models to understand the likelihood of wildfire spread (susceptibility) and pre-fire vegetation conditions. The recent launch of NASA\u27s ECOSTRESS presents an opportunity to monitor fire dynamics with a high resolution of 70 m by measuring ecosystem stress and drought conditions preceding wildfires. We incorporated ECOSTRESS data, vegetation indices, rainfall, and topographic data as independent variables and fire events as dependent variables into machine learning algorithms applied to the historic Australian wildfires of 2019–2020. With these data, we predicted over 90% of all wildfire occurrences 1 week ahead of these wildfire events. Our models identified vegetation conditions with a 3-week time lag before wildfire events in the fourth week and predicted the probability of wildfire occurrences in the subsequent week (fifth week). ECOSTRESS water use efficiency (WUE) consistently emerged as the leading factor in all models predicting wildfires. Results suggest that the pre-fire vegetation was affected by wildfires in areas with WUE above 2 g C kg−1 H₂O at 95% probability level. Additionally, the ECOSTRESS evaporative stress index and topographic slope were identified as significant contributors in predicting wildfire susceptibility. These results indicate a significant potential for ECOSTRESS data to predict and analyze wildfires and emphasize the crucial role of drought conditions in wildfire events, as evident from ECOSTRESS data. Our approaches developed in this study and outcome can help policymakers, fire managers, and city planners assess, manage, prepare, and mitigate wildfires in the future

A case report of Hashimoto’s encephalitis in a young patient: a diagnostic challenge

Encephalopathy may arise from intrinsic neurological factors or systemic illnesses. The causes can be diverse, with many being reversible. Therefore, prompt identification of the underlying cause is essential for effective patient management. Hashimoto’s encephalopathy, also known as steroid-responsive encephalopathy with autoimmune thyroiditis (SREAT), is characterized by markedly elevated antithyroid peroxidase antibody levels, suggesting an autoimmune origin. The term SREAT reflects its remarkable responsiveness to corticosteroid therapy. Being readily reversible and its response to steroids, Hashimoto's encephalopathy should be taken into consideration when investigating cases of encephalopathies where no definite aetiology is found. Diagnosis involves ruling out other potential causes, including infections, dysglycemia, electrolyte imbalances, myxedema coma, thyroid storm, hypo- and hypercortisolism, among others. This report presents the case of a 25-year-old woman with a history of hypothyroidism who presented with altered consciousness. Following the exclusion of other potential causes, a diagnosis of Hashimoto’s encephalopathy was established, and the patient responded well to intravenous steroid treatment, showing marked clinical improvement. This highlights the importance of considering this differential in treating young hypothyroid patients presenting with altered mental status