Room equalization based on iterative simple complex smoothing of acoustic impulse responses

This paper presents a room equalization method based on iterative simple complex smoothing of measured acoustic impulse responses. This is useful in cases of long duration impulse responses. Corresponding time reduced impulse responses are derived which conform to perceptual principles. The smoothed impulse responses are then used to design equalization filters. Results from an audio-conferencing reverberant room using objective and subjective tests show that we can improve the measured and perceived quality of audio reproduction

Positive solutions for three-point nonlinear fractional boundary value problems

In this paper, we give sufficient conditions for the existence or the nonexistence of positive solutions of the nonlinear fractional boundary value problem \begin{gather*} D_{0^{+}}^{\alpha}u+a(t)f(u(t))=0, 0<t<1, 2<\alpha<3,\\ u(0)=u^{\prime}(0)=0, u^{\prime}(1)-\mu u^{\prime}(\eta)=\lambda, \end{gather*} where $D_{0^{+}}^{\alpha}$ is the standard Riemann-Liouville fractional differential operator of order $\alpha$, $\eta\in\left(0,1\right)$, $\mu\in\left[0,\dfrac{1}{\eta^{\alpha-2}}\right)$ are two arbitrary constants and $\lambda\in\left[ 0,\infty\right)$ is a parameter. The proof uses the Guo-Krasnosel'skii fixed point theorem and Schauder's fixed point theorem

Impacts of indoor surface finishes on bacterial viability.

Microbes in indoor environments are constantly being exposed to antimicrobial surface finishes. Many are rendered non-viable after spending extended periods of time under low-moisture, low-nutrient surface conditions, regardless of whether those surfaces have been amended with antimicrobial chemicals. However, some microorganisms remain viable even after prolonged exposure to these hostile conditions. Work with specific model pathogens makes it difficult to draw general conclusions about how chemical and physical properties of surfaces affect microbes. Here, we explore the survival of a synthetic community of non-model microorganisms isolated from built environments following exposure to three chemically and physically distinct surface finishes. Our findings demonstrated the differences in bacterial survival associated with three chemically and physically distinct materials. Alkaline clay surfaces select for an alkaliphilic bacterium, Kocuria rosea, whereas acidic mold-resistant paint favors Bacillus timonensis, a Gram-negative spore-forming bacterium that also survives on antimicrobial surfaces after 24 hours of exposure. Additionally, antibiotic-resistant Pantoea allii did not exhibit prolonged retention on antimicrobial surfaces. Our controlled microcosm experiment integrates measurement of indoor chemistry and microbiology to elucidate the complex biochemical interactions that influence the indoor microbiome

Performance of a Hybrid Wind-Grid-Load Energy System

A hybrid energy system consisting of a wind driven generator (WG) and a power utilities grid are interconnected. The hybrid energy system provides a constant power to an AC load regardless the surrounding weather conditions. The interconnection uses a controlled single phase full wave bridge rectifier. The bridge operates in the inverter mode of operation. This is done in purpose to guaranty the extraction of the real power from the wind driven generator. The extracted power is supplied to a constant AC load and any excess of power from the wind renewable energy source is injected into the power utility grid. At any pretended surrounding weather conditions, maximum extraction of power from the renewable energy source is targeted. This is done through the realization of a self-adjusted firing angle controller responsible of triggering the semiconductor elements of the controlled bridge rectifier. The performance of the proposed system has been simulated in MATLAB/SIMULINK environment and tested practically by building a laboratory prototype model. Quite satisfactory and encouraging results have been obtained

Database and database application security

This paper focuses on the emerging importance of database and application security, textbooks and other supplementary materials to teach these topics and where to place these topics in a curriculum. The paper emphasizes 1) the growing concerns of database technologies and database applications, 2) existing books and supporting materials, and 3) and Zayed University\u27s approach to teaching these topics. At Zayed, we incorporate database and database application security in two different courses. © 2009 ACM

A Quality-of-Things Model for Assessing the Internet-of-Thing’s Non-Functional Properties

The Internet of Things (IoT) is in a “desperate” need for a practical model that would help in differentiating things according to their non-functional properties. Unfortunately, despite IoT growth, such properties either lack or ill-defined resulting into ad-hoc ways of selecting similar functional things. This paper discusses how things’ non-functional properties are combined into a Quality-of-Things (QoT) model. This model includes properties that define the performance of things’ duties related to sensing, actuating, and communicating. Since the values of QoT properties might not always be available or confirmed, providers of things can tentatively define these values and submit them to an Independent Regulatory Authority (IRA) whose role is to ensure fair competition among all providers. The IRA assesses the values of non-functional properties of things prior to recommending those that could satisfy users’ needs. To evaluate the technical doability of the QoT model, a set of comprehensive experiments are conducted using real datasets. The results depict an acceptable level of the QoT estimation accuracy

Design and experimental implementation of voltage control scheme using the coefficient diagram method based PID controller for two-level boost converter with photovoltaic system

Introduction. Currently, in the solar energy systems and a variety of electrical applications, the power converters are essential part. The main challenge for similar systems is controller design. In the literature, the PID controller has proved its effectiveness in many industrial applications, but determining its parameters remains one of the challenges in control theory field. The novelty of the work resides in the design and experimental implementation of a two-level boost DC-DC converter controlled by a PID controller for photovoltaic (PV) maximum power extraction. Purpose. Analysis and control of the two-level boost topology with renewable energy source and design of the PID controller parameters using simple and accurate method. Methods. PID coefficients are optimized using Coefficient Diagram Method (CDM) in the MATLAB environment. Results. A mathematical model of a two-level boost converter with PID controller and PV energy source was developed and analyzed. The model allows to design the controller parameters of the proposed system. Practical value. A prototype steered by the proposed CDM-PID controller was tested using an Arduino embedded board. A comparison between the simulation results and the experimental one is presented. The obtained results illustrate that the experimental results match the simulation closely, and the proposed CDM-PID controller provides a fast and precise results.Вступ. В даний час перетворювачі потужності є невід’ємною частиною сонячних енергетичних систем та різних електричних пристроїв. Основною проблемою для таких систем є проектування контролера. У літературі ПІД-регулятор довів свою ефективність у багатьох промислових застосуваннях, але визначення його параметрів залишається однією з проблем у галузі теорії управління. Новизна роботи полягає у розробці та експериментальній реалізації дворівневого підвищувального перетворювача постійного струму, керованого ПІД-регулятором, для отримання максимальної потужності фотоелектричних пристроїв. Мета. Аналіз та управління дворівневою топологією підвищення з використанням відновлюваного джерела енергії та розрахунок параметрів ПІД-регулятора простим та точним методом. Методи. Коефіцієнти ПІД оптимізуються за допомогою методу діаграми коефіцієнтів (CDM) у середовищі MATLAB. Отримані результати. Розроблено та проаналізовано математичну модель дворівневого підвищувального перетворювача з ПІД-регулятором та фотоелектричним джерелом енергії. Модель дозволяє спроєктувати параметри контролера пропонованої системи. Практична цінність. Прототип, керований пропонованим контролером CDM-PID, протестували з використанням вбудованої плати Arduino. Наведено порівняння результатів моделювання з експериментальними даними. Отримані результати показують, що експериментальні результати близько відповідають моделюванню, а пропонований CDM-ПІД-регулятор забезпечує швидкі та точні результати

Bridging the gap between business processes and IoT

© 2020 ACM. This paper discusses a novel way of making business processes and Internet of Things (IoT) work together. Indeed each suffers from many limitations that the other could help address them and vice versa. On the one hand, business processes are known for capturing organizations\u27 best practices when satisfying users\u27 demands but do not have the capabilities of controlling the physical surrounding that comprises millions of devices/things. On the other hand, IoT is known for provisioning contextualized services to users thanks to millions of devices/things but does not have the capabilities of making these devices/things collaborate. The paper presents a framework to support the collaboration of business processes and IoT. This collaboration is exemplified with 2 types of processes referred as thing-Aware processes (TaP) and process-of-Things (PoT). A system illustrating the development of PoT is presented in the paper as well