BOND-GRAPHS FOR INFORMATION SYSTEMS

Abstract

In this paper, an approach dealing with the dynamical aspect of information systems modelling is described. The main idea that governs this article is that the bond-graphs language can be applied to information systems theory. An extension of bond-graphs words is presented to cope with information exchanges. The aim of this task is to show that bond-graphs concepts can be used to model all the aspects of the information system model (static, dynamical,.).

After a brief introduction, the bond-graph language for information systems is dealt with. Particular cases and a short comparison with the Jackson software development method constitute the subject of the sections that follow, then the tools required to model the running of the information system modelled by Bond-graphs are presented. The problem is clearly presented as follows: can the energetic point of view be applied to information systems? If so, is it possible to apply the bond-graph language to those systems?     

Evaluation of Residential PV‐EV System for Supply and Demand Balance of Power System

In recent years, there has been a growing interest in ecofriendly technologies such as residential photovoltaic (PV) systems and electric vehicles (EVs). PV systems and EVs will contribute to reducing CO₂ emissions in the residential sector and the transportation sector, respectively. In spite of that, high penetration of PV systems into the power grid can cause grid voltage and frequency stability problems. Also, the growth of the EV market will create an extra electricity load (for charging the EV fleet), leading to an increase in power utility fuel costs. In this research, we proposed the usage of the PV‐EV system as a method of mitigating the impact the spread of residential PV systems and EV on the power grid. We built an PV‐EV system simulation model and investigated the PV‐EV system contribution to the balance of power supply and demand and to reducing the total cost of the household under different electricity pricing scenarios. We also evaluated the effect of uncertainty in the forecasting of load and PV output on the performance of the PV‐EV system.     

CHANGES IN THE PROFILE OF ORGANIC ACIDS IN PLAIN SET AND STIRRED YOGURTS DURING MANUFACTURE AND REFRIGERATED STORAGE1

The organic acids profile in fermented dairy foods is an indicator of the metabolic activity of added bacterial cultures. These acids act as natural preservatives and contribute to the characteristic sensory properties. This study was done to determine the effect of encapsulation on the metabolic activity of probiotic supplements, i.e. bifidobacteria, in plain yogurts. Metabolically active bifidobacteria may increase the concentration of certain organic acids, mainly acetic and propionic acids, which might lead to decreased acceptability of the product. Changes in the profiles of organic acids were determined in plain set and stirred‐type yogurts containing the starter culture and microencapsulated and nonencapsulated probiotic strains of either Bifidobacterium longumB6 or B. longum ATCC15708. Ion‐exchange high‐performance liquid chromatography was used for the separation and quantification of the organic acids. Concentrations of acetic and lactic acid increased during storage, while those of citric and uric acid remained stable. No particular pattern was observed for propionic or butyric acid, while pyruvic acid initially decreased and then increased during storage.     

Ultimate load analysis of pretensioned inverted T-beams with circular web openings

The provision of transverse openings in floor beams to facilitate the passage of utility pipes and service ducts not only results in a more systematic layout of pipes and ducts, it also translates into substantial economic savings in the construction of a multi-storey building. In this paper, ultimate load analysis of statically loaded simply supported pretensioned inverted T-beams with circular web openings is presented. Major findings relevant to ultimate load analysis of pretensioned beams with circular web openings are summarized. An attempt has been made to answer the frequently asked questions related to ultimate load analysis on multiple circular web openings. It has been shown that the analysis method for pretensioned beams with multiple large circular web openings can be further simplified without sacrificing rationality.     

尼日利亚卡它帕（树）鞣剂的潜力分析

本文分析了尼日利亚卡它帕树种的树干、树叶、果实和树皮用作皮革鞣剂的鞣性参数。实验数据表明：卡它帕树种的树皮和树叶分别含有25％和21％的鞣质。文章还提供了树皮和树干的化学分析结果及其利用途径。卡它帕树种的树此和树叶进行鞣制能得到满意的结果。