Operation Research

Assignment You are in a quality assurance unit at a certain University, and you are assigned a task of checking whether the institution is operating under control or not. The characteristic of interest is the progressive reports (in terms of GPA) of the students for the six semesters they take in a University. The population data are provided i) Explain how you would form the samples from the given data and what would be the sample size ii) Form a sample of 25 students using the procedures explained in (i), and use the appropriate control charts to check for in-control state iii) Interpret the results and advise the institution on a way forward

This paper deals with the transportation problem that
has fuzzy cost coefficient. In this paper the aim of work is to
introduce dual simplex method to solve transportation problem
with fuzzy objective functions. The fuzzy objective functions
have fuzzy demand and supply coefficients, which are
represented as fuzzy numbers. For this we are solving fuzzy
transportation problem by dual simplex method.

The typical problems facing garment manufacturers are long production lead time, bottlenecking, and low productivity. The most critical phase of garment manufacturing is the sewing phase, as it generally involves a number of operations or for the simple reason that it’s labor intensive. In assembly line balancing, allocation of jobs to machines is based on the objective of minimizing the workflow among the operators, reducing the throughput time as well as the work in progress and thus increasing the productivity. Sharing a job of work between several people is called division of labor. Division of labor should be balanced equally by ensuring the time spent at each station approximately the same. Each individual step in the assembly of product has to be analyzed carefully, and allocated to stations in a balanced way over the available workstations. Each operator then carries out operations properly and the work flow is synchronized. In a detailed work flow, synchronized line includes short distances between stations, low volume of work in process, precise of planning of production times, and predictable production quantity. This study deals with modeling of assembly line balancing by combining both manual line balancing techniques with computer simulation to find the optimal solution in the sewing line of Almeda textile plc so as to improve productivity. In this research arena software, is employed to model and measure the performance of the existing and proposed sewing line of the federal police trousers sewing line model. For each operation, the researchers have taken 15 sampling observations using stopwatch and recorded the result. All the collected data are statistically analyzed with arena input analyzer for statistical significance and determination of expressions to be used to the simulation modeling; SAM is also calculated for these operations to be used to the manual line balancing. An existing systems simulation model is developed and run for 160 replications by the researchers to measure the current performance of the system in terms of resource utilization, WIP, and waiting time. The existing systems average utilization is 0.53 with a line efficiency of 42%. This study has developed a new Sewing assembly line model which has increased the system utilization to 0.69 at a line efficiency of 58.42% without incurring additional cost.

Goodness of fit test is a test that has attracted researchers’ interest over the decades. This study is
on goodness of fit test for normal distribution only. The Kolmogorov-Smirnov (K-St) and Pearson’s
Chi-square (χ² test) goodness of fit test were used to determine the normality of a given data. The
result revealed that the data is normal under the two tests and that the Kolmogorov-Smirnov (K-S
test) were preferred to Pearson’s Chi-square (χ² test). The Kolmogorov-Smirnov (K-S) test of
goodness of fit is the most suitable in terms of the p-value.

The main approaches which are applied to select the logistic center are the methods of gravity center, analytic hierarchy process, similarity to ideal solution, fuzzy ranking, assessment, etc. Multiple Criteria Decision‐Making (MCDM) combines analytical and inductive knowledge, describing a domain problem, which can be fuzzy and/or incomplete. The fuzzy MCDM (FMCDM) approach can explain the problem more appropriately. The purpose of the paper is to select the most suitable site for logistic centre among a set of alternatives, to help the stakeholders with the performance evaluation in an uncertain environment, where the subjectivity and vagueness of criteria are described by triangular fuzzy numbers. The paper presents a newly‐developed ARAS‐F method to solve different problems in transport, construction, economics, technology and sustainable development.

—Mobile wallet is a payment platform that stores money as a value in a digital account on mobile device which can then be used for payments with or without the need for the use credit/debit cards. The cases of cyber-attacks are on the rise, posing threats to the confidentiality, integrity and availability of information systems including the mobile wallet transactions. Due to the adverse impacts of cyber-attacks on the mobile payment service providers and the users, as well as the risks associated with the use of information systems, performing risk management becomes imperative for business organizations. This research work focuses on the assessment of the vulnerabilities associated with mobile wallet transactions and performs an empirical risk management in order to derive the security priority level needed to ensure the security and privacy of the users of mobile wallet platforms. Based on the extensive literature review, a structured questionnaire was designed and administered to the mobile wallet users who are Paga student customers via the internet. A total number of 52 respondents participated in the research and their responses were analyzed using descriptive statistics. The results of the analysis show that mobile wallet Login details are the most important part of customer information that need to be highly protected as their compromise is likely to affect others. Also, customers' information such as Mobile Wallet Account Number, Registered Phone Number, Linked ATM Card details, and Linked ATM Card PIN among others are also plausible to attacks. Hence, different security priority levels were derived to safeguard each of the components and possible security tools and mechanisms are recommended. The study also revealed that there are vulnerabilities from the mobile wallet users end that also pose threat to the security of the payment system and customers' transaction which need to be properly addressed. This research work will enable the mobile payment service providers focus on their services and prioritize the security solutions for each user's information types or components base on the risks associated with their system and help in taking an inform security related decisions.

Coronary heart disease (CHD) is a slow deposition of fat on the inner wall of the
blood vessel (Heart Foundation). It is called cardiovascular disease and also a narrowing
blockage of the arteries and vessels that provide oxygen and nutrients to the heart. This work
focused on predicting the chances of CHD based on certain chosen risk factors. The data was
collected from the Federal Teaching Hospital Abakaliki, Nigeria for 100 randomly chosen
patients having one or more of the risk factors for the disease. There were patients at the age
from 20 to 69.These risk factors includes: smoking, alcohol intake, cholesterol level and diet.
The data was analyzed using logistic regression and applying SPSS version 20 package. It
was found that those who are exposed to the risk factors have their logistic function to be 1
which indicate present of the disease. Result also showed that the odds of CHD is 2.664
which indicate that they have 2.664 chances of dying with the disease or suffering from CHD
compared to those who are not at risk. The odds ratio of 0.555 for Alcohol means that there
are 0.555 times chances of dying or suffering CHD. The P-value for cholesterol and age
group indicates that there exists significant relationship and strong association of the two with
CHD. In conclusion, cholesterol and age predicts the occurrence of CHD more than other risk
factors.

Automobile manufacturing is one of the most important industries in the world. The Production Line (PL) is one of the main supply chain of this industry. The PL contains several shops and stations to complete the product. The number of workers is one variable at PL, the workers need time to weld the pieces to the structure of the car. The cycle times stations not equal in each station and shop. The unbalance cycle time stations create queuing and idle time. The Production Line Balancing Problem (PLBP) is one of the main focuses on research in automobile manufacturing. The problem in PLBP is the queuing and the idle time during task achievement that is an obstacle to efficient assembly line. Moreover, the unbalancing problems also include the number of workers among the stations. This study used a new method to solve these problems. The new method is the Multi-Objectives Model (MOM) combined with the Genetic Algorithm system (GAs). This approach is employed to solve the production li...

Dalam bersaing saat ini, perusahaan yang memproduksi durable product seperti produk elektronik, produk mesin atau alat berat umumnya dijual dengan pemberian garansi sebagai salah satu bentuk layanan purna jual. Garansi merupakan suatu perjanjian kontrak yang diberikan oleh produsen atau retailer terhadap pelanggan yang membeli produk tersebut berupa penggantian atau perbaikan apabila mengalami kerusakan selama masa periode garansi. Produk dengan masa garansi yang lama bisa dijadikan tolak ukur oleh konsumen bahwa produk tersebut memiliki kualitas yang baik. Pemberian garansi menimbulkan tambahan biaya bagi produsen maupun retailer, yang disebut dengan biaya garansi. Pada penelitian ini akan mengukur dampak terhadap penerapan strategi perpanjangan garansi yang diberikan oleh dua retailer yang berbeda dengan produsen yang sama selaku pemberi garansi dasar kepada pelanggan, dengan metode pengembangan model strategi garansi Bian dan Esmaili. Strategi perpanjangan garansi yang dilakukan ...