UML Class Diagram or Entity Relationship Diagram : An Object Relational Impedance Mismatch

It is now nearly 30 years since Peter Chen’s watershed paper “The Entity-Relationship Model –towards a Unified View of Data”. [1] The entity relationship model and variations and extensions to ithave been taught in colleges and universities for many years. In his original paper Peter Chen looked at converting his new ER model to the then existing data structure diagrams for the Network model. In recent years there has been a tendency to use a Unified Modelling Language (UML) class diagram forconceptual modeling for relational databases, and several popular course text books use UMLnotation to some degree [2] [3]. However Object and Relational technology are based on different paradigms. In the paper we argue that the UML class diagram is more of a logical model (implementation specific). ER Diagrams on theother hand, are at a conceptual level of database design dealing with the main items and their relationships and not with implementation specific detail. UML focuses on OOAD (Object Oriented Analysis and Design) and is navigational and program dependent whereas the relational model is set based and exhibits data independence. The ER model provides a well-established set of mapping rules for mapping to a relational model. In this paper we look specifically at the areas which can cause problems for the novice databasedesigner due to this conceptual mismatch of two different paradigms. Firstly, transferring the mapping of a weak entity from an Entity Relationship model to UML and secondly the representation of structural constraints between objects. We look at the mixture of notations which students mistakenly use when modeling. This is often the result of different notations being used on different courses throughout their degree. Several of the popular text books at the moment use either a variation of ER,UML, or both for teaching database modeling. At the moment if a student picks up a text book they could be faced with either; one of the many ER variations, UML, UML and a variation of ER both covered separately, or UML and ER merged together. We regard this problem as a conceptual impedance mismatch. This problem is documented in [21] who have produced a catalogue of impedance mismatch problems between object-relational and relational paradigms. We regard the problems of using UML class diagrams for relational database design as a conceptual impedance mismatch as the Entity Relationship model does not have the structures in the model to deal with Object Oriented concepts Keywords: EERD, UML Class Diagram, Relational Database Design, Structural Constraints, relational and object database impedance mismatch. The ER model was originally put forward by Chen [1] and subsequently extensions have been added to add further semantics to the original model; mainly the concepts of specialisation, generalisation and aggregation. In this paper we refer to an Entity-Relationship model (ER) as the basic model and an extended or enhanced entity-relationship model (EER) as a model which includes the extra concepts. The ER and EER models are also often used to aid communication between the designer and the user at the requirements analysis stage. In this paper when we use the term “conceptual model” we mean a model that is not implementation specific.ISBN: 978-84-616-3847-5 3594Peer reviewe

The Use of UML Class Diagrams To Teach Database Modelling and Database Design

It is now nearly 30 years since Peter Chen’s watershed paper “The Entity-Relationship Model – towards a Unified View of Data”. [1] The entity relationship model and variations and extensions to it have been taught in colleges and universities for many years. In his original paper Peter Chen looked at converting his new ER model to the then existing data structure diagrams for the Network model. In recent years there has been a tendency to use a Unified Modelling Language (UML) class diagram for conceptual modelling for relational databases, and several popular course text books use UML notation to some degree [2] [3]. This paper looks at the usefulness of using UML class diagrams for teaching database design in undergraduate courses. In this paper we look specifically at two concepts which can cause problems for the novice database designer. Firstly transferring the concept of a weak entity from an Entity Relationship model to UML and secondly the notation for structural constraints in different diagramming notations. We also look at the mixture of notations which students mistakenly use when modelling. This is often the result of different notations being used on different courses throughout their degree. Peter Chen wrote in his original paper “The entity-relationship model can be used as a tool in the structured design of databases using the network model” today we could write “the UML class diagram can be used as a tool in the structured design of databases using the relational model”. Or can we

Cyber Harassment and Women of Pakistan: Analysis of Female Victimization

Cyber harassment refers to an unwanted aggressive behavior by misusing Information Communication Technology (ICT). Cyber harassment is a grave problem all over the world, and is growing fast with the increased use of ICTs. Women are considered the core victims of cyber harassment, although men are also not exception to it. The study analyses the situation of Pakistan regarding cyber harassment of women. To probe the situation related to cyber harassment, we analyzed 68 available cases from different sources during 2012-2018. We then matched those cases with the data of Federal Investigation Agency (FIA). The results showed that comparatively a small number of cases of cyber harassment got registered and prosecuted. Out of registered cases, most of the cases were registered in the Punjab Province. Most of the victims were between the ages of 21-30 years and were well educated. Pictures sent through Facebook and cell phones were the primary source of blackmailing and harassment. The purpose of harassment is heterogeneous which is comprised of monetary benefits, revenge, and exploitation. The study suggests awareness campaigns regarding cyber harassment among women belonging to different trades and social groups. The research also suggests campaigns in society at a massive scale to create sensitization about these issues. The study further suggests training of law enforcement agencies to make them more effective in this scenario

An experimental study on axial behaviour of recycled plastic aggregate concrete columns

Plastic production and the resultant plastic waste is increasingly challenging due to population growth and urbanization. This study focuses on plastic reuse as an aggregate in concrete to explore the recycling avenue in the construction industry. In addition, the work focused on the mechanical properties of eco-friendly concrete that uses plastic waste as a partial substitution for coarse aggregate. From this method the negative impact of plastic waste on the environment not only reduced, but it also helps avoid exploitation of natural resources for natural aggregate production. Several past works have explored the use of plastic as an aggregate in concrete; however, most works were focussed on the material level behavior. In this study, compressive behaviour of reinforced concrete columns consisting of recycled plastic aggregate concrete and exposed to axial loads is investigated. This paper provides the axial loading test results of 5 columns consisting of Recycled Plastic Aggregate Concrete (RPAC). The replacement rate in the M40 grade concrete is kept at 12%. Compressive performance of RPAC columns such as strain, failure mode, reinforcement along longitudinal direction and ties spacing are analysed. The results clearly show the potential of recycled plastic aggregates for use in columns with structural performance equivalent to that of conventional aggregate concrete

Detection of Grape Clusters in Images using Convolutional Neural Network

Convolutional Neural Networks and Deep Learning have revolutionized every field since their inception. Agriculture has also been reaping the fruits of developments in mentioned fields. Technology is being revolutionized to increase yield, save water wastage, take care of diseased weeds, and also increase the profit of farmers. Grapes are among the highest profit-yielding and important fruit related to the juice industry. Pakistan being an agricultural country, can widely benefit by cultivating and improving grapes per hectare yield. The biggest challenge in harvesting grapes to date is to detect their cluster successfully; many approaches tend to answer this problem by harvest and sort technique where the foreign objects are separated later from grapes after harvesting them using an automatic harvester. Currently available systems are trained on data that is from developed or grape-producing countries, thus showing data biases when used at any new location thus it gives rise to a need of creating a dataset from scratch to verify the results of research. Grape is available in different sizes, colors, seed sizes, and shapes which makes its detection, through simple Computer vision, even more challenging. This research addresses this issue by bringing the solution to this problem by using CNN and Neural Networks using the newly created dataset from local farms as the other research and the methods used don’t address issues faced locally by the farmers. YOLO has been selected to be trained on the locally collected dataset of grapes

Optimization of dilute acid pretreatment of water hyacinth biomass for enzymatic hydrolysis and ethanol production

The present study was conducted for the optimization of pretreatment process that was used for enzymatic hydrolysis of lignocellulosic biomass (Water Hyacinth, WH), which is a renewable resource for the production of bioethanol with decentralized availability. Response surface methodology has been employed for the optimization of temperature (oC), time (hr)and different concentrations of maleic acid (MA), sulfuric acid (SA) and phosphoric acid (PA) that seemed to be significant variables with P < 0.05. High F and R2 values and low P-value for hydrolysis yield indicated the model predictability. The pretreated biomass producing 39.96 g/l, 39.86 g/l and 37.9 g/l of reducing sugars during enzymatic hydrolysis with yield 79.93, 78.71 and 75.9 % from PA, MA and SA treated respectively. The order of catalytic effectiveness for hydrolysis yield was found to be phosphoric acid > maleic acid > sulfuric acid. Mixture of sugars was obtained during dilute acid pretreatment with glucose being the most prominent sugar while pure glucose was obtained during enzymatic hydrolysis. The resulting sugars, obtained during enzymatic hydrolysis were finally fermented to ethanol, with yield 0.484 g/g of reducing sugars which is 95 % of theoretical yield (0.51 g/g glucose) by using commercial baker’s yeast (Sacchromyces cerveasiae)

Foreign Direct Investment Lead to Exports of Pakistan: An Econometric Evidence

The objective of the study is to empirically analyze that whether foreign direct investment lead to exports of Pakistan for the period from 1972 to 2014. Econometric results are estimated using Partial Adjustment Model for long run as well short run and then some diagnostic statistics are also applied for reliability of results. Long run and short run results propose positive influence of foreign direct investment, exchange rate, trade openness, and real GDP of Pakistan while inflation is found to have inverse effect of exports of Pakistan. Further tests indicate regression model free from Autocorrelation, Heteroskedasticity, abnormality of residuals and dynamic instability problems. Keywords: Foreign Direct Investment, Real GDP, Exports, Exchange Rate, Inflation

Cough, Hemoptysis and Hair Expectoration: An Intrapulmonary Teratoma

Teratomas can be found in different organs of the body and may involve gonads, saccrococcygeal region, mediastinum and other sites. Intrathoracic teratomas always occur in mediastinum and less often arise within the lung. As teratomas mostly involve sex organs (gonads), they rarely occur as extra-gonadal tumors accounting for only 3% of all the cases and very small percentage of such tumors occur in mediastinum.We reported an interesting case of middle aged male who presented to us with symptoms of cough, hemoptysis and trichoptysis (hair expectoration).We found that patient had intrapulmonary teratoma that was initially being treated as case of pulmonary tuberculosis. He underwent surgical resection of his cavitatory lesion and diagnosis of intrapulmonary teratoma was confirmed by histopathology as well. The patient made remarkable recovery with complete disappearance of his symptoms. From Pakistan no such case has ever been reported. Although it is very unusual but in patient with cavitatory lesion, intrapulmonary teratoma should always be kept in mind as differential diagnosis