Simulation of product transportation in open pit mines

A research report submitted to the Faculty of Engineering and Built Environment, University of Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Masters of Science in Engineering Johannesburg, 2015Open pit mines account for more than 60 percent of all surface mines, and haulage costs account for almost 60 percent of total operating costs for these mines. It necessitates maintaining an efficient haulage system where all fleet equipment performs effectively to achieve the mine’s objectives. Discrete event simulation supported by animation offers a powerful method for evaluating such systems. This research has developed a simulation software program using Visual Basic for Application (VBA), GPSS/H (General Purpose Simulation System), and PROOF 5 animation. Remaining within the defined assumptions and boundary conditions, the research combines the powers of three software languages to build a general-purpose, data-driven, and user-friendly simulation program. The research focuses on the study and simulation of some of the important complexities of the truck haulage system. These include uncertainty or system randomness, fleet heterogeneity, multi-loader multi-dump sites, bunching of haulers, and hauler dispatching. In the developed simulation program, the user is required to provide the inputs in the user-friendly environment of VBA. The simulation program arranges the inputs in a pre-arranged format and then sends them to GPSS/H. The simulation language generates a discrete event simulation model based on the receiving structural and operational data. After simulating the system, the model generates the simulation outputs and animation commands in separate files. VBA displays a summary of the simulation results, and PROOF 5 demonstrates the results in a 2-dimensional graphical animation along with detailed information. This research also includes three case studies based on hypothetical mines for the analysis of simulation results. It establishes comparisons between the dispatching policies of fixed allocation and variable allocation of Minimize Production Requirements (MPR), and shows that the MPR policy is more suitable to achieve the quality control objectives. The developed simulation program contributes by demonstrating the powers of simulation to analyse open pit haulage systems. It also shows how simulation can be utilized as a useful technique to answer many ‘what-if?’ questions and scenarios

Posterior Mediastinal Chondrosarcoma- A rare entity

Introduction:Chondrosarcoma is a well defined tumor of soft tissue with calcification. Extraskeletal myxoid chondrosarcoma is an unusual sarcoma of soft tissue adding only 3% to all soft tissue tumors. Majority of mediastinal foci originates from variety of tissues, the reason being their diverse embryological and anatomical approximations. Chondrosarcomas are more common in males with 2:1 male to female ratio. The exact pathology of these tumors is unclear; however recent data ensures that these tumors have multidirectional delineation. Classical histopathological features of chondrosarcoma include S-100 positivity, EMA positivity. These features of Immunohistochemical favor extra skeletal myxoid chondrosarcoma.Case Report:Recent data signifies that the tumor is known for its rare occurrence, here we have reported a unique case of 40 years old male visited Abbasi Shaheed Hospital for pre employment checkup without any symptoms. All the tests were negative except Chest X-ray PA view which revealed dense mass on lower lobe of lung. For further evaluation, CT scan of chest with contrast was ordered and eventually the mass was resected surgically. On the basis of macro and microscopic findings, histopathological tests and immunohistochemical stains, the mass was found to be chondrosarcoma with myxoid origin. This tumor has to be distinguishing among the list of different diseases like hamartoma, hydatid cyst, and neuroendocrine tumors for the differential diagnosis of the case.Conclusion: Our paper reports an extraskeletal mesenchymal chondrosarcoma originating in the posterior mediastinum with a rare presentation.Â

Demutualization of Stock Exchanges in Pakistan and its Comparison with International Scenario

This topic of research is carrying great importance for Karachi Stock Exchange as it compares the most important issue of demutualization with international case studies. In this report advantages and criticism of the demutualization in Pakistan is discussed. The process followed by the Australian Stock Exchange and Toronto Stock Exchange is highlighted so as to do a comparative study. Along with the demutualization integration of the exchanges is also discussed, as a result of which two alternatives are derived. Recommendations in the context of the implementation of the demutualization process are given and one of the suggested alternatives is given the preference for the implementation in Pakistan exchanges

HESITANCY TOWARDS ONLINE SHOPPING, A STUDY OF PAKISTANI CONSUMERS

To study the influence of Perceived cost, risk, convenience and enjoyment on online consumer purchases. Being more convenient online shopping seems painless compared to in store shopping, why consumers are still reluctant to shop online?.A sample of 220 questionnaires was filled from different departments at University of Sargodha. Respondents were asked to fill the questionnaire based on four factors (Perceived cost, Perceived risk, Perceived convenience, Perceived enjoyment), there were 2 general questions. Out of 220, 207 questionnaires were returned. One sample test is applied in this study to check the reliability of independent variables. Analysis was also done on basis of gender and their ages. The most important factor out of four, which can persuade the customer's online buying decision, is delivery cost for purchased items and it has negative relationship with dependent variable, moreover perceived risk has also negative relationship with dependent one. Perceived convenience and Perceived enjoyment has positive relationship with online shopping preference. As online shopping is easier to do but due to extra delivery cost and risk factors consumers do not adopt online shopping and these factors should be minimized to promote online shopping. Online shopping should be promoted and to gain the consumer confidence, delivery cost and risk factor should be minimized. As online shopping is easier to do as compared to offline shopping but people still reluctant to use internet for online shopping, so to promote online shopping delivery cost and risk factor should be minimized to gain consumers attraction and confidence. People want to experience online shopping but it won’t be promoted until delivery cost and perceived risk factors be reduced. A little work has been done on exploring the factors that influence the online buying decision. These factors are called situational factors and include delivery charges, risk factors, convenience factors and enjoyment factors. In Pakistan consumers are not too much affiliated to online shopping as compared to European countries and not too much researches have been done related to online shopping in Pakistan , so this research been conducted to promote online shopping

Size premium, value premium and market timing: evidence from an emerging economy

Purpose - This study aims to investigate the market timing strategy in different market conditions (i.e. up, down, normal and in-financial-crisis situation) in the emerging market of Pakistan over the period 1995 to 2015. Furthermore, this study tests the validity of the capital asset pricing model (CAPM) and Fama and French model. Design/methodology/approach - This study considers monthly stock returns of 167 firms and constructs six different portfolios on the basis of different size and book to market ratio. The Treynor and Mazuy model is used to capture the market timing strategy. Findings - The results indicate evidence of the market timing in normal market conditions. However, there is less supportive evidence of market timing in up-market, down-market and in-financial-crisis situations. This study also confirms the validity of the capital asset pricing model and Fama and French three-factor model with strong support of value premium and size premium in the stock market. Practical implications - The findings of this study are helpful to companies in estimating the cost of issuing equity more accurately. The investors can use market timing to make their investment in a more better and profitable manner. Originality/value - Unlike other previous studies, this study considers an extended period to test the validity of the capital asset pricing model and Fama and French model. In addition, this study is novel in testing the marketing timing of the firms in the context of emerging economy of Pakistan.Objetivo - Este estudio tiene como objetivo investigar la estrategia de sincronización del mercado en diferentes condiciones de mercado (es decir, situación al alza, a la baja, normal y en situación de crisis financiera) en el mercado emergente de Pakistán durante el período 1995 a 2015. Además, este estudio prueba la validez de la modelo de valoración de activos de capital (CAPM) y modelo Fama y francés. Diseño / metodología / enfoque - Este estudio considera los rendimientos mensuales de las acciones de 167 empresas y construye seis carteras diferentes sobre la base de diferentes tamaños y relaciones entre libros y mercado. El modelo de Treynor y Mazuy se utiliza para capturar la estrategia de sincronización del mercado. Recomendaciones - Los resultados indican evidencia de la sincronización del mercado en condiciones normales de mercado. Sin embargo, hay menos evidencia de apoyo de la sincronización del mercado en situaciones de mercado al alza, a la baja y en situaciones de crisis financiera. Este estudio también confirma la validez del modelo de fijación de precios de los activos de capital y el modelo de tres factores de Fama y el francés con un fuerte apoyo de la prima de valor y la prima de tamaño en el mercado de valores. Implicaciones prácticas - Los hallazgos de este estudio son útiles para que las empresas estimen con mayor precisión el costo de emisión de acciones. Los inversores pueden utilizar la sincronización del mercado para hacer su inversión de una manera mejor y más rentable. Originalidad / valor - A diferencia de otros estudios anteriores, este estudio considera un período extendido para probar la validez del modelo de valoración de activos de capital y el modelo francés y de Fama. Además, este estudio es novedoso al probar el momento de comercialización de las empresas en el contexto de la economía emergente de Pakistán

An Empirical Analysis of the Linder

This paper presents empirical evidence in support of the Linder theory of international trade for three of the South Asian countries, Bangladesh, India, and Pakistan. This finding implies that these countries trade more intensively with countries of other regions, which may have similar per capita income levels, as predicted by Linder in his hypothesis. The contribution of this research is threefold: first, there is new information on the Linder hypothesis by focusing on South Asian countries; second, this is one of very few analyses to capture both time-series and cross-section elements of the trade relationship by employing a panel data set; third, the empirical methodology used in this analysis corrects a major shortcoming in the existing literature by using a censored dependent variable in estimation.

SAM-SoS: A stochastic software architecture modeling and verification approach for complex System-of-Systems

A System-of-Systems (SoS) is a complex, dynamic system whose Constituent Systems (CSs) are not known precisely at design time, and the environment in which they operate is uncertain. SoS behavior is unpredictable due to underlying architectural characteristics such as autonomy and independence. Although the stochastic composition of CSs is vital to achieving SoS missions, their unknown behaviors and impact on system properties are unavoidable. Moreover, unknown conditions and volatility have significant effects on crucial Quality Attributes (QAs) such as performance, reliability and security. Hence, the structure and behavior of a SoS must be modeled and validated quantitatively to foresee any potential impact on the properties critical for achieving the missions. Current modeling approaches lack the essential syntax and semantics required to model and verify SoS behaviors at design time and cannot offer alternative design choices for better design decisions. Therefore, the majority of existing techniques fail to provide qualitative and quantitative verification of SoS architecture models. Consequently, we have proposed an approach to model and verify Non-Deterministic (ND) SoS in advance by extending the current algebraic notations for the formal models as a hybrid stochastic formalism to specify and reason architectural elements with the required semantics. A formal stochastic model is developed using a hybrid approach for architectural descriptions of SoS with behavioral constraints. Through a model-driven approach, stochastic models are then translated into PRISM using formal verification rules. The effectiveness of the approach has been tested with an end-to-end case study design of an emergency response SoS for dealing with a fire situation. Architectural analysis is conducted on the stochastic model, using various qualitative and quantitative measures for SoS missions. Experimental results reveal critical aspects of SoS architecture model that facilitate better achievement of missions and QAs with improved design, using the proposed approach