What are the factors associated with sanitation and hygiene behaviours, an investigation in Giong Trom district, Ben Tre province in the Mekong river Delta region of Vietnam?

Poor sanitation and hygiene are still one of the pressing challenges in the developing world with not only serious health and but also non-health consequences. Diarrheal diseases, for example, are preventable by handwashing and hygienic latrine, still kill more than 4500 children every day, more than that of measles, malaria and HIV combined. Its non-health consequences include welfare loss, dignity, economic and financial losses...Vietnam had a rural sanitation coverage of only 65% despite the great amount of investment (mainly in hardware provision) in rural sanitation and hygiene over the last 25 years. Behaviour change interventions, therefore, are necessary if the country is to achieve Universal Sanitation and good hygiene by 2030 as it committed. Consequently, an understanding of the population’s sanitation and hygiene behavioural determinants is required in order to design efficient and effective intervention programs. This thesis is based on the RANAS model using data surveyed in Giong Trom district, Ben Tre Province (of the provinces with lowest rural sanitation coverage in Vietnam). It has 3 objectives: to identify behavioural determinants and factors associated to a range of sanitation and hygiene behaviours; to identify, measure and compare to health and non-health impact associated with different sanitation conditions; to propose and recommend evidence-backed interventions aimed at improving rural sanitation and hygiene. Having employed the logistic and multiple linear regression analysis, the thesis found the key factors associated with the following sanitation and hygiene behaviours: • Hygienic latrine ownership: Source of income, poverty certificate possession, instrumental beliefs, perceived cost. • Unhygienic latrine ownership (while already having hygienic latrine ownership): Location, disgust, user preference, personal norm. • Hygienic latrine regular use: Gender, vulnerability perception, Instrumental beliefs, user preference, descriptive norm. • Handwashing with soap: Knowledge, user preference, disgust, volitional self-efficacy. • Forgetting handwashing with soap: Gender, knowledge, user preference, disgust, descriptive norm, injunctive norm, volitional self-efficacy, motivational self-efficacy. In addition, the thesis didn't find clear cut evidence on the health impact of different sanitation conditions due to the fact that it isn't possible to attribute any diseases solely to poor sanitation. However, it found strong evidence that poor sanitation conditions had significant negative welfare impact on the households. Finally, it demonstrated how a recent intervention program -the WASOBA project- was successful in Ben Tre in increasing hygienic latrine ownership because it addressed directly the key determinant factors identified by this thesis

Incidences between points and generalized spheres over finite fields and related problems

Let $\mathbb{F}_q$ be a finite field of $q$ elements where $q$ is a large odd prime power and $Q =a_1 x_1^{c_1}+...+a_dx_d^{c_d}\in \mathbb{F}_q[x_1,...,x_d]$, where $2\le c_i\le N$, $\gcd(c_i,q)=1$, and $a_i\in \mathbb{F}_q$ for all $1\le i\le d$. A $Q$-sphere is a set of the form $\lbrace x\in \mathbb{F}_q^d | Q(x-b)=r\rbrace$, where $b\in \mathbb{F}_q^d, r\in \mathbb{F}_q$. We prove bounds on the number of incidences between a point set $\mathcal{P}$ and a $Q$-sphere set $\mathcal{S}$, denoted by $I(\mathcal{P},\mathcal{S})$, as the following. $$| I(\mathcal{P},\mathcal{S})-\frac{|\mathcal{P}||\mathcal{S}|}{q}|\le q^{d/2}\sqrt{|\mathcal{P}||\mathcal{S}|}.$$ We prove this estimate by studying the spectra of directed graphs. We also give a version of this estimate over finite rings $\mathbb{Z}_q$ where $q$ is an odd integer. As a consequence of the above bounds, we give an estimate for the pinned distance problem. In Sections $4$ and $5$, we prove a bound on the number of incidences between a random point set and a random $Q$-sphere set in $\mathbb{F}_q^d$. We also study the finite field analogues of some combinatorial geometry problems, namely, the number of generalized isosceles triangles, and the existence of a large subset without repeated generalized distances.Comment: to appear in Forum Mat

Development of Multi-Robotic Arm System for Sorting System Using Computer Vision

This paper develops a multi-robotic arm system and a stereo vision system to sort objects in the right position according to size and shape attributes. The robotic arm system consists of one master and three slave robots associated with three conveyor belts. Each robotic arm is controlled by a robot controller based on a microcontroller. A master controller is used for the vision system and communicating with slave robotic arms using the Modbus RTU protocol through an RS485 serial interface. The stereo vision system is built to determine the 3D coordinates of the object. Instead of rebuilding the entire disparity map, which is computationally expensive, the centroids of the objects in the two images are calculated to determine the depth value. After that, we can calculate the 3D coordinates of the object by using the formula of the pinhole camera model. Objects are picked up and placed on a conveyor branch according to their shape. The conveyor transports the object to the location of the slave robot. Based on the size attribute that the slave robot receives from the master, the object is picked and placed in the right position. Experiment results reveal the effectiveness of the system. The system can be used in industrial processes to reduce the required time and improve the performance of the production line

A Critique of Chen's "The 2-MAXSAT Problem Can Be Solved in Polynomial Time"

In this paper, we examine Yangjun Chen's technical report titled ``The 2-MAXSAT Problem Can Be Solved in Polynomial Time'' [Che23], which revises and expands upon their conference paper of the same name [Che22]. Chen's paper purports to build a polynomial-time algorithm for the ${\rm NP}$-complete problem 2-MAXSAT by converting a 2-CNF formula into a graph that is then searched. We show through multiple counterexamples that Chen's proposed algorithms contain flaws, and we find that the structures they create lack properly formalized definitions. Furthermore, we elaborate on how the author fails to prove the correctness of their algorithms and how they make overgeneralizations in their time analysis of their proposed solution. Due to these issues, we conclude that Chen's technical report [Che23] and conference paper [Che22] both fail to provide a proof that ${\rm P}={\rm NP}$.Comment

AlertTrap: A Study on Object Detection in Remote Insect Trap Monitoring System Using on the Edge Deep Learning Platform

Fruit flies are one of the most harmful insect species to fruit yields. In AlertTrap, implementation of Single-Shot Multibox Detector (SSD) architecture with different state-of-the-art backbone feature extractors such as MobileNetV1 and MobileNetV2 appears to be potential solutions for the real-time detection problem. SSD-MobileNetV1 and SSD-MobileNetV2 perform well and result in AP at 0.5 of 0.957 and 1.0, respectively. You Only Look Once (YOLO) v4-tiny outperforms the SSD family with 1.0 in AP at 0.5; however, its throughput velocity is considerably slower, which shows SSD models are better candidates for real-time implementation. We also tested the models with synthetic test sets simulating expected environmental disturbances. The YOLOv4-tiny had better tolerance to these disturbances than the SSD models. The Raspberry Pi system successfully gathered environmental data and pest counts, sending them via email over 4 G. However, running the full YOLO version in real time on Raspberry Pi is not feasible, indicating the need for a lighter object detection algorithm for future research. Among model candidates, YOLOv4-tiny generally performs best, with SSD MobileNetV2 also comparable and sometimes better, especially in scenarios with synthetic disturbances. SSD models excel in processing time, enabling real-time, high-accuracy detection. TFLITE versions of SSD models also process faster than their inference graph on TPU hardware, suggesting real-time implementation on edge devices like the Google Coral Dev Board. The results demonstrate the feasibility of real-time implementation of the fruit fly detection models on edge devices with high performance. In addition, YOLOv4-tiny is shown to be the most probable candidate because YOLOv4-tiny demonstrates a robust testing performance toward citrus fruit fly detection. Nevertheless, SSD-MobileNetV2 will be the better model, considering the inference time

Optical Hall response of bilayer graphene: the manifestation of chiral hybridised states in broken mirror symmetry lattices

Understanding the mechanisms governing the optical activity of layered-stacked materials is crucial to the design of devices aimed at manipulating light at the nanoscale. Here, we show that both twisted and slid bilayer graphene are chiral systems that can deflect the polarization of linear polarized light. However, only twisted bilayer graphene supports circular dichroism. Our calculation scheme, which is based on the time-dependent Schr\"odinger equation, is particularly efficient for calculating the optical-conductivity tensor. Specifically, it allows us to show the chirality of hybridized states as the handedness-dependent bending of the trajectory of kicked Gaussian wave packets in bilayer lattices. We show that nonzero Hall conductivity is the result of the noncanceling manifestation of hybridized states in chiral lattices. We also demonstrate the continuous dependence of the conductivity tensor on the twist angle and the sliding vector.Comment: 24 pages, 6 figure