Erasure-Resilient Sublinear-Time Graph Algorithms

We investigate sublinear-time algorithms that take partially erased graphs represented by adjacency lists as input. Our algorithms make degree and neighbor queries to the input graph and work with a specified fraction of adversarial erasures in adjacency entries. We focus on two computational tasks: testing if a graph is connected or ε-far from connected and estimating the average degree. For testing connectedness, we discover a threshold phenomenon: when the fraction of erasures is less than ε, this property can be tested efficiently (in time independent of the size of the graph); when the fraction of erasures is at least ε, then a number of queries linear in the size of the graph representation is required. Our erasure-resilient algorithm (for the special case with no erasures) is an improvement over the previously known algorithm for connectedness in the standard property testing model and has optimal dependence on the proximity parameter ε. For estimating the average degree, our results provide an “interpolation” between the query complexity for this computational task in the model with no erasures in two different settings: with only degree queries, investigated by Feige (SIAM J. Comput. ‘06), and with degree queries and neighbor queries, investigated by Goldreich and Ron (Random Struct. Algorithms ‘08) and Eden et al. (ICALP ‘17). We conclude with a discussion of our model and open questions raised by our work.

Difficulties in the interpretation of kinematics graphs in secondary basic education students

This research reports the findings derived from the identification of the difficulties exhibited by a group of 76 students from different grades of basic secondary education in a private educational institution with an emphasis on science education. The students were given a questionnaire presenting five situations based on the Position-Time graph associated with uniform rectilinear motion of particles. The research approach is of a quantitative nature at a descriptive level with a field design, since it was the students who filled in the instrument. It is highlighted as a finding in the opinion of the students that the subject has been seen in class, but due to the teacher’s methodology it is not fully understood by them. The results show that the students have a long list of difficulties mainly due to the lack of articulation of mathematical concepts in physical contexts, a situation that prevents them from analyzing the proposed statements, reasoning about the approaches, and improving in the process of searching for alternative solutions with clear arguments.

The analysis of the 2019 annular solar eclipse with simple instruments for developing student worksheet

The annular solar eclipse occurred when the Earth-Moon-Sun position aligned in the same line where the angular diameter of the moon is smaller than the angular diameter of the sun due to the moon is on the farthest distance with respect to the earth. The event was observed on 26 December 2019 at Siak Regency, Province of Riau, Indonesia. Based on that event observation, the sun is gradually covered by the moon until the peak event where the sun is completely covered and showing “ring of fire”. All stages of eclipse are captured as images from DSLR camera that been attached into telescope with specific filter as well as illumination determination from observation location using lux meter during the event. This study explained how to get the information from solar eclipse images available by using image-processing software namely ImageJ so it can be used as a student worksheet. The plotting of both pixel area-time graph and illumination-time graph of this study shows a similar trend. Therefore, the data acquired in this study is obtained well so it can be used as a student worksheet in the Astronomical Position lecture based on the actual phenomenon with a simple instrument for observation.

An Anthropocentric and Enhanced Predictive Approach to Smart City Management

Cities are becoming increasingly complex to manage, as they increase in size and must provide higher living standards for their populations. New technology-based solutions must be developed towards attending this growth and ensuring that it is socially sustainable. This paper puts forward the notion that these solutions must share some properties: they should be anthropocentric, holistic, horizontal, multi-dimensional, multi-modal, and predictive. We propose an architecture in which streaming data sources that characterize the city context are used to feed a real-time graph of the city’s assets and states, as well as to train predictive models that hint into near future states of the city. This allows human decision-makers and automated services to take decisions, both for the present and for the future. To achieve this, multiple data sources about a city were gradually connected to a message broker, that enables increasingly rich decision-support. Results show that it is possible to predict future states of a city, in aspects such as traffic, air pollution, and other ambient variables. The key innovative aspect of this work is that, as opposed to the majority of existing approaches which focus on a real-time view of the city, we also provide insights into the near-future state of the city, thus allowing city services to plan ahead and adapt accordingly. The main goal is to optimize decision-making by anticipating future states of the city and make decisions accordingly.

Displacement-Time Graph of a Point on a Wave Pulse

Using a linear substitution of distance by velocity and time, it is shown how a displacement-time profile of a particle on a wave pulse is graphed.

MOBILE CARDIAC TELEMETRY SYSTEM FOR ISOLATED IMMUNOSUPPRESSED PATIENTS

This article represents an experiment for a portable open-source ECG monitoring system, purposed for isolated immunosuppressed patients, with heart conditions. At the current stage of development, the proposed experimental MCT (Mobile Cardiac Telemetry) system can be wirelessly used in conjunction with a smart phone and a real-time graph streaming application, through the BLE (Bluetooth Low Energy) module of an IoT embedded platform. At the moment, the system is intended for autonomous low power consumption and short wireless proximity range suited for close monitoring of patients by themselves at home, or by the medical staff in the isolated hospital ward rooms or mobile isolation containters.

Design of a Wireless Single Arm Electrocardiograph System

Electrocardiograms (ECGs) are a method of assessment of cardiac electrical activity. It is the heart’s electrophysiological activity which occurs by the conduction of electrical impulses from the Sinoatrial (SA) node and the Atrioventricular (AV) node across the cardiac muscles and is displayed as a voltage-time graph. Conventionally, they have been acquired using a system of ten surface electrodes placed in different locations throughout the body in a 12-lead system. Single Arm ECG systems, where the ECG rhythm is obtained from only a single part of the body, replace the need for ten different electrodes to detect the heart's activity. Three pre-gelled electrodes are applied in different locations of the left arm to derive the sinus rhythm signal of a subject. An op-amp based hardware instrument has been developed for this purpose with active filters and amplifiers to perform signal conditioning. This paper demonstrates the implementation of a single arm hardware system of small size to improve portability, used as an ECG detection method and the results from various subjects taken at different gain values to improve the view of the signal, while also presenting a method to transmit the data of the signals wirelessly through an Internet-of-things (IoT) platform.