Achieving Optimal Throughput and Near-Optimal Asymptotic Delay Performance in Multi-Channel Wireless Networks with Low Complexity: A Practical Greedy Scheduling Policy

In this paper, we focus on the scheduling problem in multi-channel wireless networks, e.g., the downlink of a single cell in fourth generation (4G) OFDM-based cellular networks. Our goal is to design practical scheduling policies that can achieve provably good performance in terms of both throughput and delay, at a low complexity. While a class of $O(n^{2.5} \log n)$-complexity hybrid scheduling policies are recently developed to guarantee both rate-function delay optimality (in the many-channel many-user asymptotic regime) and throughput optimality (in the general non-asymptotic setting), their practical complexity is typically high. To address this issue, we develop a simple greedy policy called Delay-based Server-Side-Greedy (D-SSG) with a \lower complexity $2n^2+2n$, and rigorously prove that D-SSG not only achieves throughput optimality, but also guarantees near-optimal asymptotic delay performance. Specifically, we show that the rate-function attained by D-SSG for any delay-violation threshold $b$, is no smaller than the maximum achievable rate-function by any scheduling policy for threshold $b-1$. Thus, we are able to achieve a reduction in complexity (from $O(n^{2.5} \log n)$ of the hybrid policies to $2n^2 + 2n$) with a minimal drop in the delay performance. More importantly, in practice, D-SSG generally has a substantially lower complexity than the hybrid policies that typically have a large constant factor hidden in the $O(\cdot)$ notation. Finally, we conduct numerical simulations to validate our theoretical results in various scenarios. The simulation results show that D-SSG not only guarantees a near-optimal rate-function, but also empirically is virtually indistinguishable from delay-optimal policies.Comment: Accepted for publication by the IEEE/ACM Transactions on Networking, February 2014. A preliminary version of this work was presented at IEEE INFOCOM 2013, Turin, Italy, April 201

Budget-Feasible Mechanism Design for Non-Monotone Submodular Objectives: Offline and Online

The framework of budget-feasible mechanism design studies procurement auctions where the auctioneer (buyer) aims to maximize his valuation function subject to a hard budget constraint. We study the problem of designing truthful mechanisms that have good approximation guarantees and never pay the participating agents (sellers) more than the budget. We focus on the case of general (non-monotone) submodular valuation functions and derive the first truthful, budget-feasible and $O(1)$-approximate mechanisms that run in polynomial time in the value query model, for both offline and online auctions. Prior to our work, the only $O(1)$-approximation mechanism known for non-monotone submodular objectives required an exponential number of value queries. At the heart of our approach lies a novel greedy algorithm for non-monotone submodular maximization under a knapsack constraint. Our algorithm builds two candidate solutions simultaneously (to achieve a good approximation), yet ensures that agents cannot jump from one solution to the other (to implicitly enforce truthfulness). Ours is the first mechanism for the problem where---crucially---the agents are not ordered with respect to their marginal value per cost. This allows us to appropriately adapt these ideas to the online setting as well. To further illustrate the applicability of our approach, we also consider the case where additional feasibility constraints are present. We obtain $O(p)$-approximation mechanisms for both monotone and non-monotone submodular objectives, when the feasible solutions are independent sets of a $p$-system. With the exception of additive valuation functions, no mechanisms were known for this setting prior to our work. Finally, we provide lower bounds suggesting that, when one cares about non-trivial approximation guarantees in polynomial time, our results are asymptotically best possible.Comment: Accepted to EC 201

Circular economy : can it be an effective economic re-design?

Circular Economy recently has gained massive attention in terms of its implications across multiple industrial verticals. Various schools of thoughts like permaculture, cradle to cradle, industrial symbiosis have been associated with the Circular Economy, yet the application of circular practices is still relatively low. This research addresses the gaps between the theory and practice and analyses the reasons why there is the delay in its application. Moreover, the research also reflects on the understanding of Circular Economy with its circular business models and how those business models can tackle and address the challenges in the traditional linear production systems. Apart from this, the benefits for the key stakeholders in the economy i.e., corporations, governments and consumers have been identified and explained. Multiple case research methodology has been followed to understand the ground reality of the delay in the application of circular economy, four industrial verticals have been chosen and using a semi-structured interview process, various examples, strategies, opportunities and challenges have been understood and they form the analytical structure of the research. The research then uses the results from the case study to be interpreted by using the theory of absorptive capacity in an open innovation system and hence the results are analyzed accordingly, concluded with the understanding of technological, leadership, consumer behavior enabling factors and the monopoly played by corporations as a disabler. Moreover, the recommendations are directed towards the government enabling stricter EPR (Extended Producer Responsibility) and post occupancy evaluation regulations.A Economia Circular tem ganho recentemente grande atenção em termos das suas implicações em vários setores industriais. Várias escolas de pensamento, como a permacultura, o gradle-to-gradle, a simbiose industrial, entre outros, têm sido associadas à Economia Circular, embora a implementação de práticas circulares ainda seja relativamente baixa. Esta pesquisa aborda as lacunas entre a teoria e prática, e analisa as principais razões que têm atrasado a sua implementação. A pesquisa reflete ainda o entendimento da Economia Circular com seus modelos de negócios circulares, e como esses modelos de negócios podem enfrentar os desafios dos tradicionais sistemas de produção linear. Além disso, foram também identificados e explicados os benefícios para os principais stakeholders na economia (corporações, governos e consumidores). Foi aplicada a metodologia de pesquisa de casos múltiplos para entender a realidade do atraso na implementação da economia circular: foram escolhidos quatro setores industriais, e, usando um processo de entrevista semi-estruturada, foram analisados vários exemplos, estratégias, oportunidades e desafios, que formam a estrutura analítica da pesquisa. A pesquisa usou os resultados do estudo de caso, interpretando-os com base na teoria da capacidade absortiva num sistema de inovação aberta. De seguida, os resultados foram analisados adequadamente, e concluídos com a compreensão de fatores tecnológicos, de liderança, de comportamento do consumidor e do monopólio pelas corporações como uma barreira. Além disso, as recomendações foram direcionadas para o Governo, permitindo uma aplicação mais rigorosa do EPR (Extended Producer Responsibility) e regulamentos de avaliação pós-ocupação

Colposcopic evaluation of unhealthy cervix and its correlation with pap smear and cervical biopsy

Background: Carcinoma cervix is the second most common gynecological malignancy amongst Indian women aged 25-44 years after carcinoma breast. But it is preventable as it has a long pre-invasive phase. Various methods are available for screening the cervical cancer which can detect disease in early stages of pre-invasive phase. Present study has been conducted to see the correlation of colposcopy, histopathology and Pap smear. This study aimed to screen women with PAP smear and colposcopy who have abnormal symptoms and to compare and correlate colposcopy and cytology with histopathology. Further, this study aimed to evaluate the sensitivity and specificity of colposcopy versus pap smear in the early detection of dysplasias. Methods: This study was conducted in the department of obstetrics and gynecology at AMCH, Shahbad from 1st January 2021 to 31st December 2022. This was a prospective clinical study on 200 randomly selected women who fulfilled selection criteria. They underwent Pap smear, colposcopy and cervical biopsy according to the criteria after informed consent. Results: This study showed that colposcopy had high sensitivity (82%) and a low specificity (81%) when compared to Pap smear. In the present study, the accuracy of colposcopic impression was found to be 82%. Conclusions: CIN lesions and early invasive cancers should be diagnosed in an earlier stage for instituting appropriate management. Colposcopy is definitely more sensitive and accurate than pap smear. By combining pap smear with colposcopy, we can maximise the sensitivity and specificity of cancer cervix screening

Morphological changes in placenta in cases of oligohydramnios

Background: There are gross and microscopic changes in placenta and umbilical cord in complicated pregnancies. The objective of this study was to study pathological (gross and microscopic) changes in placenta, membrane and umbilical cord in cases with oligohydramnios and to study relationship between changes in placenta, membranes and umbilical cord with severity of oligohydramnios.Methods: A total of 50 patients were selected and their placentas were collected after delivery and sent to pathology department in 10 % formalin for histopathological examination. Patients were divided into three groups and the results were compared. Statistical calculations were performed using the SPSS 16.0. In order to detect differences between subjects students t-test was used for continuous variables, while, for categorical variables, the X2 test was used. A p-value of less than 0.05 was considered statistically significant.Results: Atotal of 50 patients were studied for a period of one year and following observations were made, discoid shape placenta in 45 (90.0%), oval in 5 (10.0%), central attachment of umbilical cord in 16 cases (32.0%), eccentric in 33 (66.0%), marginal in 1 (2.0%) case following variables were compared and p value detected, placental maximum diameter (p <0.0001),placental minimum diameters (p = 0.041), mean of cord length (p <0.0001) placental weight (p = 0.273), placental thickness (p = 0.253), acute chorioamnionitis (p <0.0001), chronic chorioamnionitis (p<0.0001), focal squamous metaplasia (p <0.0001), bacterial colonies in subamnion (p <0.0001), meconium staining (p <0.0001), amnion nodosum (p < 0.0001), intra amniotic haemorrhage (p = 0.090), membranous deciduitis with chorioamnionitis (p = 0.081), focal haematoma (p = 0.010), acute inflammatory infiltrate in Wharton’s jelly (p = 0.012), single umbilical artery (p =0.010), intervillous fibrin deposition (p <0.0001), calcification (p<0.0001), chorangiosis (p <0.0001), syncytial knots (p <0.0001), avascular villi (p = 0.011), villous edema (p = 0.090) and infarct (p = 0.090).Conclusions: There are alterations in placental morphology associated with oligohydramnios hence placenta should be examined, which may be useful in predicting perinatal morbidity and mortality

Comparative evaluation of laparoscopic hysterectomy and non-descent vaginal hysterectomy in women with benign gynaecological disease

Background: Hysterectomy is one of the most frequently performed gynaecological operative procedure all over world, second most to caesarean section in United States. The aim of study was to compare the intraoperative and postoperative complications in patients undergoing non-descent vaginal hysterectomy (NDVH) and Laparoscopic hysterectomy (LH) for benign gynaecological disease.Methods: The prospective one-year study was conducted on 156 patients who required hysterectomy for benign gynaecological conditions. After applying inclusion and exclusion criteria, 75 patients assigned to Group A (NDVH) and 75 to Group B (LH) and both groups were compared.Results: On comparing the two groups there was statistically significant decrease in the duration of surgery (p<0.01, t = 11.65), pain score (p<0.01, t = 2.75) and blood transfusion requirement (p = 0.03, χ2 = 4.80) in group A, while blood loss (p = 0.73, t = 0.33), uterine volume (p = 0.15, t = 1.43), time taken to ambulate (p = 0.06 , t = 0.21), duration of hospital stay (p = 0.07, t = 1.80), conversion to laparotomy (p = 0.13, χ2 = 2.56), febrile morbidity (p = 0.27, χ2 = 1.34), infection (p = 0.42, χ2 = 1.11) and visceral injury was found statistically insignificant.Conclusions: Vaginal hysterectomy is an easier technique with shorter duration of surgery and with minimal infrastructure required and for fixed uterus or huge adnexal mass laparoscopic hysterectomy (LH) should be preferred