A Reinforcement Learning Framework with Region-Awareness and Shared Path Experience for Efficient Routing in Networks-on-Chip

Network-on-chip (NoC) architectures provide a scalable, high-performance, and reliable interconnect for emerging manycore systems. The routing policies used in NoCs have a significant impact on overall performance. Prior efforts have proposed reinforcement learning (RL)-based adaptive routing policies to avoid congestion and minimize latency in NoCs. The output quality of RL policies depends on selecting a representative cost function and an effective update mechanism. Unfortunately, existing RL policies for NoC routing fail to represent path contention and regional congestion in the cost function. Moreover, the experience of packet flows sharing the same route is not fully incorporated into the RL update mechanism. In this paper, we present a novel regional congestion-aware RL-based NoC routing policy called Q-RASP that is capable of sharing experience from packets using the same routes. Q-RASP improves average packet latency by up to 18.3% and reduces NoC energy consumption by up to 6.7% with minimal area overheads compared to state-of-the-art RL-based NoC routing implementations

Constructing a subgradient from directional derivatives for functions of two variables

For any scalar-valued bivariate function that is locally Lipschitz continuous and directionally differentiable, it is shown that a subgradient may always be constructed from the function's directional derivatives in the four compass directions, arranged in a so-called "compass difference". When the original function is nonconvex, the obtained subgradient is an element of Clarke's generalized gradient, but the result appears to be novel even for convex functions. The function is not required to be represented in any particular form, and no further assumptions are required, though the result is strengthened when the function is additionally L-smooth in the sense of Nesterov. For certain optimal-value functions and certain parametric solutions of differential equation systems, these new results appear to provide the only known way to compute a subgradient. These results also imply that centered finite differences will converge to a subgradient for bivariate nonsmooth functions. As a dual result, we find that any compact convex set in two dimensions contains the midpoint of its interval hull. Examples are included for illustration, and it is demonstrated that these results do not extend directly to functions of more than two variables or sets in higher dimensions.Comment: 16 pages, 2 figure

Green hydrogen production from photovoltaic power station as a road map to climate change mitigation

The increasing recognition of hydrogen as a critical element in the global net-zero transition and its clear role in decarbonizing challenging sectors coincide with the growing urgency to address climate change. Africa's favourable renewable-energy capacity, ranging from 28% to 36% for solar, has been reported by the global solar irradiance index. However, the majority of hydrogen production today relies on fossil fuels (96%), with only a small fraction (4%) being produced through water electrolysis. Even though there have been many studies on climate change mitigation with a focus on Africa, a green hydrogen production from a photovoltaic power station approach has not been reported. Also, literature with a focus on Nigeria is lacking. This study focuses on the African green hydrogen production industry, utilizing Nigeria as a case study to explore the feasibility of generating clean hydrogen vectors from a percentage of photovoltaic power output in various regions of the country through stand-alone solar grid electrification projects. Analyses of the usage and effectiveness of the produced hydrogen fuel in each region are carried out, with the highest region having an annual output of 12 247 278 kg of green hydrogen and 8 573 094 kg of ammonia and the lowest region having an output of 511 245 kg of green hydrogen and 357 871 kg of ammonia, and the expected production from the proposed usage of 50% of the power generation output of the installed 1.6-MWp and 80-kWp solar power minigrids in the regions is calculated. The analyses were repeated for the other considered regions in the country. The results showcased the enormous advantages of the electrolytic production of hydrogen and how the greener economy project can play a major role in mitigating climate change effects and overreliance on fossil fuels as the driver of the economy in many African countries

Five year evaluation of the complications observed in porcelain fused to metal (PFM) crowns placed at a university hospital

Objective: To determine the frequency of complications in crowns cemented over a 5-year period in a tertiary care hospital and also to report the survival of these crowns.Methods: The retrospective cross-sectional study was conducted at the Aga Khan University Hospital, Karachi, from March 2017 to March 2018 and comprised porcelain fused-to-metal crowns placed on the anterior or posterior teeth that were fabricated at the institutional laboratory and were placed in institutional dental clinics in the preceding 5 years. Porcelain-fused to-metal The crowns were clinically and radio-graphically evaluated in a duration of two months for presence/absence of complications. Factors associated with the failure of the crowns, their survival and the impact of covariates, like gender, flossing and bruxism, on the survival time were determined. Data was analysed using SPSS 22.Results: There were 150 crowns related to 107 patients who had a mean age of 45.0±11.4 years. The most common complication observed was open proximal contacts 9(6%) followed by de-cementation 8(5.3%), porcelain chipping 9(6%) and abutment fracture 2(1.3%). The 5-year survival rate of the crowns was 127(84.7%). The mean follow-up time was 57.2±1.0 months. Overall, year-wise survival of PFM crowns for one year till five years was 147 (98%), 144 (96%), 135 (90%), 130 (86%) and 119 (79%) respectively.Conclusions: The porcelain-fused-to-metal crowns had a high 5-year survival rate. Open proximal contacts represented the most common complication

Bibliometric study on the literature related to dental research and education published in Journal of Pakistan Medical Association

Objective: To analyse characteristics of literature related to dental research and education published in a single medical journal, The Journal of Pakistan Medical Association.Method: The bibliometric study was conducted at the Sindh Institute of Oral Health Sciences, Jinnah Sindh Medical University from March till May 2020, and comprised electronic and hand search of scientific literature relevant to dentistry published in the Journal of Pakistan Medical Association from the first issue published in 1953 till March 2020. The selected articles were analysed for year of publication, field of study, type of article, institute and country of first author, number of authors and citation count. Keyword mapping was also carried out. Data was analysed using SPSS 19.Results: Of the 159 articles identified, 117(73.6%) were contributed from Pakistan. The most common specialties were Oral and Maxillofacial Surgery and Epidemiology with 20(12.6%) articles each, followed by Operative Dentistry and Endodontics 19(11.9%). Majority of articles were Original / Research 87(54.7%). The highest number of articles were published in 2019 26(16.35%). The Aga Khan University, contributed the most publications 30(18.9%), followed by Dow University of Health Sciences, 11(6.9%). Majority of the articles were contributed by three authors 48(38.4%). The top cited article was found to have 113 citations, followed by articles with 103 and 91 citations.Conclusions: The contribution of scientific papers related to dentistry and dental education in the Journal of Pakistan Medical Association was significant. With growth of dentistry as a discipline along with a parallel increase in the publication of dental research papers, it is imperative that a dedicated indexed journal for dental research be commenced

Awareness of dentists regarding immediate management of dental avulsion : Knowledge, attitude, and practice study.

OBJECTIVE: To assess the knowledge of practising dentists regarding immediate management of dental avulsion. METHODS:The cross-sectional analytical study was conducted in various dental colleges and teaching hospitals of Karachi, Pakistan, in October-November 2016, and comprised dentists working in academic institutions / departments or as general dental practitioners for at least 1 year. The subjects were asked to fill out a self-administered questionnaire. Questions related to knowledge and practice regarding immediate management of dental avulsion was asked and then responses were categorised as good knowledge, moderate and poor knowledge. SPSS 22 was used for data analysis.. RESULTS: Of the 282 subjects, 179 (63.5%) were females and 103(36.5%) were males. The overall mean age was 28. 33±4.7 years, and 194 (68.8%) had clinical experience of less than 5 years. Of the total, 30(11%) dentists had good knowledge while 130(46%) had moderate and 122(43%) had poor knowledge. Statistically significant association of knowledge regarding tooth avulsion was observed with the specialty (p= 0.006) and qualification (p=0.001). CONCLUSIONS: The knowledge of dentists regarding immediate management of avulsion injuries was inadequate. Knowledge was significantly associated with specialty and qualification of the dentist

Radiographic evaluation of the margins of clinically acceptable metal-ceramic crowns

Objective: To radiographically evaluate the proximal marginal fit of the clinically acceptable metal-ceramic crowns. Methods: The prospective study was conducted at the dental clinics of Aga Khan University, Karachi, from July to December 2018, and comprised metal-ceramic crowns that were evaluated prior to the cementation. Clinical examinations were conducted by seating the crown on the tooth preparation and visual assessment was done using sharp explorer along the margins. Clinically acceptable crowns were then evaluated on the bite-wing radiograph. Any horizontal or vertical inaccuracy of \u3e0.5mm at the proximal margins was recorded as \u27discrepancy\u27. Data was analysed using SPSS 22. Results: Of the 230 interproximal margins of 115 crowns evaluated, 113(49.1%) sites had marginal discrepancies; 44(19.1%) horizontal discrepancies, 58(25.2%) vertical discrepancies, and 11(4.8%) having both horizontal and vertical discrepancies. Horizontal crown margin discrepancies were most associated with the mesial site of the maxillary crowns, while vertical discrepancies were commonly associated with the distal aspect of all crowns (p\u3c0.050). Conclusions: Almost half of the crowns that were considered clinically acceptable had some vertical or horizontal marginal discrepancy on radiographic evaluation

Full mouth functional and aesthetic rehabilitation of a patient affected with hypoplastic type of amelogenesis imperfecta

The management of Amelogenesis imperfecta often poses a challenge for the dentists. It not only includes aesthetic and functional rehabilitation of the patient, but also requires a positive rapport building with the patient due to psychosocial issues. The treatment plan is driven by patient demands, age, cost-affordability, severity of the disease and the presenting condition. The present case report elucidates step by step management of a 20 year-old female who presented with generalized hypersensitivity, intermittent pain associated with multiple decayed posterior teeth, poor dental aesthetics and anterior deep bite. The management consisted of endodontic treatments in all teeth, crown lengthening to gain ferrule in some teeth, provision of provisional bridges at an increased vertical dimension for six weeks followed by full mouth all ceramic crowns on all teeth. The prosthetic management aimed at reorganized occlusal scheme. There was a significant improvement in the aesthetics, deep bite, and along with correction of the vertical dimension of occlusion