Adaptive Lock-Free Data Structures in Haskell: A General Method for Concurrent Implementation Swapping

A key part of implementing high-level languages is providing built-in and default data structures. Yet selecting good defaults is hard. A mutable data structure's workload is not known in advance, and it may shift over its lifetime - e.g., between read-heavy and write-heavy, or from heavy contention by multiple threads to single-threaded or low-frequency use. One idea is to switch implementations adaptively, but it is nontrivial to switch the implementation of a concurrent data structure at runtime. Performing the transition requires a concurrent snapshot of data structure contents, which normally demands special engineering in the data structure's design. However, in this paper we identify and formalize an relevant property of lock-free algorithms. Namely, lock-freedom is sufficient to guarantee that freezing memory locations in an arbitrary order will result in a valid snapshot. Several functional languages have data structures that freeze and thaw, transitioning between mutable and immutable, such as Haskell vectors and Clojure transients, but these enable only single-threaded writers. We generalize this approach to augment an arbitrary lock-free data structure with the ability to gradually freeze and optionally transition to a new representation. This augmentation doesn't require changing the algorithm or code for the data structure, only replacing its datatype for mutable references with a freezable variant. In this paper, we present an algorithm for lifting plain to adaptive data and prove that the resulting hybrid data structure is itself lock-free, linearizable, and simulates the original. We also perform an empirical case study in the context of heating up and cooling down concurrent maps.Comment: To be published in ACM SIGPLAN Haskell Symposium 201

Software Quality Assurance-Challenges in Launch Vehicle Projects

Launch vehicle projects now depend on software, more than ever before, to ensure safetyand efficiency. Such critical software syfiems, which can lead to injury, destruction or loss ofvital equipment, human lives, and damage to environment, must be developed and verified withhigh level of quality and reliability. An overview of current quality practices pursued in launchvehicle projects is presented in this paper. These practices have played a vital role in the successfullaunch vehicle missions of Indian Space Research Organisation. As complexity of softwareincreases, the activity that gets affected is nothing but, software quality assurance (SQA). TheSQA team is facing a lot of challenges in current practices. This paper brings out such challengesin different phases of software life cycle. A set of key points to some techniques and tools, thatcould contribute to meet the software quality 'assurance challenges in launch vehicle projects,are also discussed

Complexity in Technology Choices and Market Access for Pigeon Pea Growers in Semi-Arid Tropics of India

India, being the largest producer, consumer and importer of pulses, its demand and supply influences global pulses sector significantly. For several years, there has been consistent import of different types of pulse-grains by India, despite having the largest area under cultivation and their total production. This paper focuses mainly on the production of pigeon pea, second most produced and consumed pulse after chickpea. There has been a major shift in the pigeon pea production in the country. The study is an attempt to examine the adoption of modern variety and other production practices in the highest pigeon pea producing state of India viz. Maharashtra. The marketing behaviour of the pigeon pea growers is also the focus area of this study. The pigeon pea production in India varied dramatically over the last five decades, in terms of its spread, productivity and its importance as an intercrop. At the farmers’ level, there is a need for proper intervention in cropping patterns through new and improved crop varieties, information dissemination to farmers, mechanization and service support in reducing operational costs of farmers so as to increase the profitability from pigeon pea cultivation. The lot size and conveniences in terms of distance and time flexibility are some of the major influencers to decide about the marketing destination for the pigeon pea growers in the region

Reinstatement and Lectotypification of Memecylon deccanense (Melastomataceae): An Endemic Species of the Western Ghats, India.

As part of the ex-situ conservation of the wild ornamental plants at JNTBGRI, several species of Memecylon were collected and introduced from the Western Ghats. While working on the taxonomy of the collected plants, it was found that a well defined species Memecylon deccanense C.B.Clarke  has been reduced recently to the synonym of M.heyneanum Benth. ex Wight & Arn. A detailed study by relevant literature, live and herbarium specimens, and type specimens housed at different herbaria, it is reinstated as a distinct species and a lectotype is designated here. Relevant photographs and images of type specimens of M.deccanense and M.heyneanum also provided to facilitate its easy identification

Truncated Access to Institutional Agricultural Credit as a Major Constraint for Rural Transformation: Insights from Longitudinal Village Studies

The study has examined the trend of formal credit growth and its influence on rural transformation in terms of accelerating growth in household income levels. It has also identified the factors influencing the access to formal agricultural credit in the study regions, viz. eastern and semi-arid tropics (SAT) of India. The longitudinal household level data of about 1200 households in three states each in these two regions have been analysed for the period 2010 to 2013. The study has observed that the poor access to formal credit has compelled these households to take loan from informal sources who sometimes charge interest @ 60 to 120 per cent per annum, threatening the livelihoods of these smallholders and poor households. During the study period of three years (2010 - 2013), no change in situation was visible in these villages and the access to formal sources of agricultural credit seems to remain truncated. The main reasons for this disturbing trend is the lack of institutional framework to provide cheap and subsidized credit to these marginal and landless households, who take land on lease for cultivation. The Tobit model has been fitted to determine the accessibility to formal agricultural credit in these regions. The study has highlighted the need of building a strong and inclusive financial infrastructure to provide necessary credit support to the smallholder farmers in the eastern and SAT regions for bringing a rapid rural transformation

Smart Agriculture Land Crop Protection Intrusion Detection Using Artificial Intelligence

Human-wildlife conflict is the term used to describe when human activity results in a negative outcome for people, their resources, wild animals, or their habitat. Human population growth encroaches on wildlife habitat, resulting in a decrease in resources. In particular habitats, there are numerous forms of human and domesticated animal death or injury as a result of conflict. Farmers and the animals that invade farmland suffer greatly as a result. Our project’s primary objective is to lessen human-animal conflict and loss. The embedded system and image processing technique are utilized in the project. Python is used to perform image processing techniques like segmentation, statistical and feature extraction using expectation maximization, and classification using CNN. The classification is used to determine whether the land is empty or if animals are present. A buzzer sound is produced, a light electric current is passed to the fence, and a message alerting the farmer to the animal’s entry into the farmland is transmitted. This prevents the animal from entering the field and enables the landowner to take the necessary steps to get the animal back to the forest. The result is serially sent to the controller broad from the control board

Refinement Reflection:Complete Verification with SMT

We introduce Refinement Reflection, a new framework for building SMT-based deductive verifiers. The key idea is to reflect the code implementing a user-defined function into the function's (output) refinement type. As a consequence, at uses of the function, the function definition is instantiated in the SMT logic in a precise fashion that permits decidable verification. Reflection allows the user to write equational proofs of programs just by writing other programs using pattern-matching and recursion to perform case-splitting and induction. Thus, via the propositions-as-types principle, we show that reflection permits the specification of arbitrary functional correctness properties. Finally, we introduce a proof-search algorithm called Proof by Logical Evaluation that uses techniques from model checking and abstract interpretation, to completely automate equational reasoning. We have implemented reflection in Liquid Haskell and used it to verify that the widely used instances of the Monoid, Applicative, Functor, and Monad typeclasses actually satisfy key algebraic laws required to make the clients safe, and have used reflection to build the first library that actually verifies assumptions about associativity and ordering that are crucial for safe deterministic parallelism.Comment: 29 pages plus appendices, to appear in POPL 2018. arXiv admin note: text overlap with arXiv:1610.0464

Farmer Producer Organization in Andhra Pradesh: A Scoping Study. Rythu Kosam Project. Research Report IDC-16.

The declining profitability and rising risk associated with agriculture and allied its activities is being considered some of the major challenges in improving the livelihoods of the rural population in India. Mainly small and marginal farmers constitute the largest group of cultivators (about 85%) in Indian agriculture; having smaller than or about two hectares of operational holdings. The vulnerability to these households is largely attributed to lower scale of operation, lack of information, poor access to cheaper credit, weak participation in the consumers’ markets and consequently, exploitation by intermediaries in procuring inputs and marketing of their produce. A variety of approaches have emerged over the years to address these problems. Agricultural cooperatives, formed under the Co-operative Credit Societies Act, 1904, have long been the dominant form of farmer collectives; however, the experience with cooperatives point to many limitations, except few successful exceptions in the field of dairy farming. In recent years, collectivization of producers, especially small and marginal farmers, into producer organizations has emerged as one of the most effective pathways to address the many challenges of agriculture. Hence, on the recommendations of a high-power committee, the Government of India introduced the Companies (Amendment) Act 2002, which paved the way to Producer Companies (PCs)..

Psychosocial Assessment of Candidates for Transplantation (PACT) Score Identifies High Risk Patients in Pediatric Renal Transplantation

Background: Currently, there is no standardized approach for determining psychosocial readiness in pediatric transplantation. We examined the utility of the Psychosocial Assessment of Candidates for Transplantation (PACT) to identify pediatric kidney transplant recipients at risk for adverse clinical outcomes.Methods: Kidney transplant patients <21-years-old transplanted at Duke University Medical Center between 2005 and 2015 underwent psychosocial assessment by a social worker with either PACT or unstructured interview, which were used to determine transplant candidacy. PACT assessed candidates on a scale of 0 (poor candidate) to 4 (excellent candidate) in areas of social support, psychological health, lifestyle factors, and understanding. Demographics and clinical outcomes were analyzed by presence or absence of PACT and further characterized by high (≥3) and low (≤2) scores.Results: Of 54 pediatric patients, 25 (46.3%) patients underwent pre-transplant evaluation utilizing PACT, while 29 (53.7%) were not evaluated with PACT. Patients assessed with PACT had a significantly lower percentage of acute rejection (16.0 vs. 55.2%, p = 0.007). After adjusting for HLA mismatch, a pre-transplant PACT score was persistently associated with lower odds of acute rejection (Odds Ratio 0.119, 95% Confidence Interval 0.027–0.52, p = 0.005). In PACT subsection analysis, the lack of family availability (OR 0.08, 95% CI 0.01–0.97, p = 0.047) and risk for psychopathology (OR 0.34, 95% CI 0.13–0.87, p = 0.025) were associated with a low PACT score and post-transplant non-adherence.Conclusions: Our study highlights the importance of standardized psychosocial assessments and the potential use of PACT in risk stratifying pre-transplant candidates

Facilitating Adolescent Well-Being: A Review of the Challenges and Opportunities and the Beneficial Roles of Parents, Schools, Neighborhoods, and Policymakers

Adolescents face exceptional challenges and opportunities that may have a lifelong impact on their consumption and personal and societal well-being. Parents, community members (schools and neighborhoods), and policymakers play major roles in shaping adolescents and influencing their engagement in consumption behaviors that are either developmentally problematic (e.g., drug use and unhealthy eating) or developmentally constructive (e.g., academic pursuits and extracurricular activities). In this article, we discuss two main topics: (a) the challenges and opportunities that characterize adolescence, based primarily on research in epidemiology and neuroscience, and (b) the ways that parents, community members, and policymakers can facilitate positive adolescent development, based on research from many disciplines including marketing, psychology, sociology, communications, public health, and education. Our goal is to summarize the latest scientific findings that can be used by various stakeholders to help adolescents navigate this turbulent period and become well-adjusted, thriving adults