Revisiting Robustness in Priced Timed Games

Priced timed games are optimal-cost reachability games played between two players---the controller and the environment---by moving a token along the edges of infinite graphs of configurations of priced timed automata. The goal of the controller is to reach a given set of target locations as cheaply as possible, while the goal of the environment is the opposite. Priced timed games are known to be undecidable for timed automata with $3$ or more clocks, while they are known to be decidable for automata with $1$ clock. In an attempt to recover decidability for priced timed games Bouyer, Markey, and Sankur studied robust priced timed games where the environment has the power to slightly perturb delays proposed by the controller. Unfortunately, however, they showed that the natural problem of deciding the existence of optimal limit-strategy---optimal strategy of the controller where the perturbations tend to vanish in the limit---is undecidable with $10$ or more clocks. In this paper we revisit this problem and improve our understanding of the decidability of these games. We show that the limit-strategy problem is already undecidable for a subclass of robust priced timed games with $5$ or more clocks. On a positive side, we show the decidability of the existence of almost optimal strategies for the same subclass of one-clock robust priced timed games by adapting a classical construction by Bouyer at al. for one-clock priced timed games

Uterine low grade endometrial stromal sarcoma: a case report with review of literature

Endometrial stromal sarcomas are rare uterine tumours usually seen in perimenopausal females. We report here a case of low grade endometrial stromal sarcoma in a 45 year female with a clinical diagnosis of fibroid uterus and final histological diagnosis of low grade endometrial stromal sarcoma

Stochastic Timed Games Revisited

Stochastic timed games (STGs), introduced by Bouyer and Forejt, naturally generalize both continuous-time Markov chains and timed automata by providing a partition of the locations between those controlled by two players (Player Box and Player Diamond) with competing objectives and those governed by stochastic laws. Depending on the number of players - 2, 1, or 0 - subclasses of stochastic timed games are often classified as 2 1/2-player, 1 1/2-player, and 1/2-player games where the 1/2 symbolizes the presence of the stochastic "nature" player. For STGs with reachability objectives it is known that 1 1/2-player one-clock STGs are decidable for qualitative objectives, and that 2 1/2-player three-clock STGs are undecidable for quantitative reachability objectives. This paper further refines the gap in this decidability spectrum. We show that quantitative reachability objectives are already undecidable for 1 1/2 player four-clock STGs, and even under the time-bounded restriction for 2 1/2-player five-clock STGs. We also obtain a class of 1 1/2, 2 1/2 player STGs for which the quantitative reachability problem is decidable

Histopathology of endometrium in abnormal uterine bleeding, in correlation with thyroid profile and ultrasonography findings

Background: Abnormal uterine bleeding is the cause for many disturbances in women who are in the reproductive age group. Frequent and prolonged periods will lead to morbidity, social embarrassment, diminished quality of life and compromise of the sexual life.Methods: It is a hospital based cross sectional study conducted in the department of pathology, Andhra medical college. A total of 270 patients in the age group of 18 to 45 years were included in this study. Endometrial samples were obtained and histopathological examinations were conducted. All the clinical details and investigation reports were collected.Results: The age group of patients in this study ranged from 18 to 45 years. Maximum numbers of cases (169) were in the age group of 36 to 45 years (62.6%). Most of the patients were multipara (244 cases, 90.37%) and most common presenting complaint was heavy menstrual bleeding (198 cases, 73.3%). Majority of the patients were euthyroid (247 cases, 91.5%). Normal cyclical endometrium was found to be the commonest histopathological pattern with proliferative endometrium in 45.56% and secretory endometrium in 32.59% cases. Leiomyomas were found to be the commonest cause of abnormal uterine bleeding (15.56%). Bulky / enlarged uterus (77%) and type-IV (hyperechoic) endometrium, depicting the secretory endometrial pattern (36.66%) was the most common finding on transvaginal sonography (TVS).Conclusions: Histopathological examination is the gold standard for studying the pattern of endometrium in various causes of abnormal uterine bleeding

Role of Machine Learning in Education: Performance Tracking and Prediction of Students

Accurately predicting students’ future performance based on their ongoing academic records is crucial for effectively carrying out necessary pedagogical interventions to ensure students’ on-time and satisfactory graduation. Although there is a rich literature on predicting student performance when solving problems or studying for courses using data-driven approaches, predicting student performance in completing degrees (e.g. college programs) is much less studied and faces new challenges: (1) Students differ tremendously in terms of backgrounds and selected courses; (2) Courses are not equally informative for making accurate predictions; (3) Students’ evolving progress needs to be incorporated into the prediction. In this paper, we develop a novel machine learning method for predicting student performance in degree programs that is able to address these key challenges. The proposed method has two major features. First, a bi-layered structure comprising of multiple base predictors and a cascade of ensemble predictors is developed for making predictions based on students’ evolving performance states. Second, a data-driven approach based on latent factor models and probabilistic matrix factorization is proposed to discover course relevance, which is important for constructing efficient base predictors. Through extensive simulations on an undergraduate student dataset collected over three years at UCLA, we show that the proposed method achieves superior performance to benchmark approaches

Detection of Electricity Theft Cyber-Attacks In Renewable Distributed Generation for Future IoT-based Smart Electric Meters

Electricity theft represents a pressing problem that has brought enormous financial losses to electric utility companies worldwide. In the United States alone, $6 billion worth of electricity is stolen annually. Traditionally, electricity theft is committed in the consumption domain via physical attacks that includes line tapping or meter tampering. The smart grid paradigm opens the door to new forms of electricity theft attacks. First, electricity theft can be committed in a cyber manner. With the advanced metering infrastructure (AMI), smart meters are installed at the customers’ premises and regularly report the customers’ consumption for monitoring and billing purposes. In this context, malicious customers can launch cyber-attacks on the smart meters to manipulate the readings in a way that reduces their electricity bill. Second, the smart grid paradigm enables customers to install renewable-based distributed generation (DG) units at their premises to generate energy and sell it back to the grid operator and hence make a profit

Improved Undecidability Results for Reachability Games on Recursive Timed Automata

We study reachability games on recursive timed automata (RTA) that generalize Alur-Dill timed automata with recursive procedure invocation mechanism similar to recursive state machines. It is known that deciding the winner in reachability games on RTA is undecidable for automata with two or more clocks, while the problem is decidable for automata with only one clock. Ouaknine and Worrell recently proposed a time-bounded theory of real-time verification by claiming that restriction to bounded-time recovers decidability for several key decision problem related to real-time verification. We revisited games on recursive timed automata with time-bounded restriction in the hope of recovering decidability. However, we found that the problem still remains undecidable for recursive timed automata with three or more clocks. Using similar proof techniques we characterize a decidability frontier for a generalization of RTA to recursive stopwatch automata

Development of an IoT-Based QR Code Access Control and Payment System using Arduino and ESP8266

In this research, we present the development and implementation of an IoT-based access control and payment system utilizing QR code technology, Arduino microcontroller, and ESP8266 Wi-Fi module. The system is designed to enhance security and streamline payment processes in various applications such as parking lots, public transport, and restricted access areas. The core components include an ESP camera for QR code scanning, a Liquid Crystal Display (LCD) for user feedback, and a pair of motors to control physical barriers. Upon scanning a QR code, the system verifies its validity and either grants access or denies it based on pre-set criteria. For valid QR codes, the system deducts a specified amount from the user’s balance, displays the updated balance on the LCD, and operates the motors to allow entry. Invalid QR codes trigger an audio alert via a buzzer. The system communicates transaction data to a remote server using the ESP8266 module, ensuring real-time logging and monitoring. The project highlights the integration of hardware components with software modules to achieve a robust and efficient access control solution. By leveraging IoT technologies, the system offers improved security, real-time data processing, and automated transaction handling. This research contributes to the field of IoT-based automation by demonstrating a practical application in access management and payment systems, providing a scalable and versatile solution for modern access control challenges