Wirtschaftsingenieurwesen und Management

This research investigates a no-wait hybrid flow shop scheduling problem. Minimizing the mean tardiness is considered as the objective to develop the optimal scheduling algorithm. Characteristics of our considered problem leads to the complexity of problem. First, no-wait operations. Second, setup time of each job is separated from its processing time and depends upon its preceding job. Third, all of jobs aren’t available at the first of scheduling. In other word, each job has individual ready time. Finally, machines are not continuously available due to the preventive maintenance. An effective harmony search algorithm is used to tackle the mentioned problem. A series of computational experiments is conducted by comparing our algorithm with previous meta-heuristic algorithms like population based simulated annealing (PBSA), Adopted imperialist competitive algorithm (ICA) and hybridization of PBSA and ICA (ICA+PBSA). To achieve reliable results, Taguchi approach is used to define robust parameters’ values for our proposed algorithm. The computational results with random test problems suggest that our proposed harmony search outperforms the three foregoing algorithms.

At the present time most of Ethiopian leather manufacturing industries are facing tough competition globally due to deteri-orated quality of leather. Clearly known that poor quality results in increasing manufacturing cost. Lastly, the industry becomes unprofitable. In addition, the industries are forced to lose their customers. Sheba leather Industry PLC is one of Ethiopian leather manufacturing industry facing this problem. So, the purpose of the project is to decrease extreme trimmed and rejected leather, to introduce a system that is capable of solving the problem, to expand findings to other sections of the industry. There was a problem of trimmed and rejected skin leather at re-tanning and crust preparation section. 14,879.92 kg of trimmed skin leather and 8,164 pieces of rejected leather. The problem solving methodology approach was used during the project work to reduce both trimmed and rejected leather. Quality control 7 tools were also applied as per the nature of the steps of problem solving. The findings after completion of the implementation period the excessive trimmed leather is reduced to 8,524 kg by 42.71% improvement. The rejected leather of minimized to 5,241 pieces of leather by 35.80% improvement. In addition, systems like standard operation procedure, standardization of four basic autonomous maintenance activities, quality control process chart and operator skill analysis are introduced on potential areas. Besides, the area of the finished leather also improves by 2.2% relative to the input size of the leather. Finally, the department managers took responsibility to sustain the substantial improvements and expand these systems to hide production section of the company.

Although about half of the workforce is women, there is no country in the world where a woman earns the same as a man for doing the same job. It is estimated that it takes several decades to close the gender gap. The reported gender gap has been 34% in the US in 2014, that is, female workers made year-round only 66 cents for every dollar earned by men doing the same job. This paper aims to study whether there is any wage discrimination in The Commonwealth of The Bahamas in regards to gender and its connection to education. We will also investigate whether higher education is associated with a higher wages. In this study, we have collected the data through survey from the Bahamian people working in The Bahamas. Inferential and descriptive statistics are applied to perform the analysis.

Knitted fabrics bursting strength dependency was investigated. The investigation was by reviewing previously done and published research articles. In this investigation the dependency of bursting strengths on knit structures was identified and analyzed. Different findings of different scholars on bursting strengths of different knitted fabrics have been discussed in this review.

The economic rate of return (ERR) is a measure of the profitability of a revenue generating investment based on a single external discount rate which is the hurdle rate or the minimum attractive rate of return (MARR).

In this paper, we will highlight on the practical and reasonable interpretation of the (ERR) as a reinvestment rate of the present worth of costs. We shall give the usual mathematical definition of the (ERR) and derive an alternative, more useful, and applicable definition in terms of the benefit-cost ratio. We will also investigate the behavior of the (ERR) function in terms of the (MARR) as a variable. A relationship between the (ERR) and the internal rate of return (IRR) will be established. Finally, the applicability of the (ERR) method as an economic analysis method will be demonstrated.

The philosophy of Build-In-Reliability (BIR) or Design for Reliability (DFR) emphasizes the value of reliability prediction at a product’s conceptual design stage. Due to the lack of reliability data, reliability assessment of a new design is not usually performed at this stage. In this paper, we propose a methodology to provide the reliability insight of a new design concept. The methodology consists of three major processes: functional analysis, cognitive map and Bayesian network modeling. A case study is given to demonstrate our proposed method.

This paper presents a review of the literature on lean leadership practices. We begin with a brief review of the literature on lean origins and history, followed by a quick introduction to lean principles, building blocks, and prominent implementation frameworks in the literature, and conclude by reviewing the scarce literature on the focused subject of lean leadership in terms of tools, practices, attributes, and frameworks. A critical gap has been identified in the literature with regards to a holistic and practical leadership model for companies that are willing to make a changeover to a lean business system. This review reveals the need for a meticulously developed leadership model based on empirical evidence. It also discusses the necessity of developing new lean tools for leadership or adapting the existing lean tools to leadership tasks.

Background/objectives: Recently, convergent products are introduced in digital products. Fast assembly and new product development and dynamic product configuration are all considered in convergent product concept. The fast technology development and dynamic customer demands require a more efficient and flexible system for new product development. This paper proposes an integrated decision making model for convergent product evaluation under fuzzy environment.
Methods/statistical analysis: First the fuzzy decision matrix is formed and using fuzzy PROMETHEE the pairwise comparison is performed. Then, by fuzzy linear programming (FLP) the weights of the functions with respect to attributes pairwise matrices are obtained. Finally, the fuzzy output is transformed to crisp one employing fuzzy analytic hierarchy process (FAHP). The contribution are in developing a new fuzzy linear program, integrate it with PROMETHEE and using them in convergent product function evaluation.
Findings: The results are helpful in business plan and road map of businesses for obtaining competitive advantage and profit maximization. Some of the products are considered and customers’ views are collected to form a new product converging the requirements asked by customer’s altogether. The dynamic customer views make the system responsive to different convergent products.
Application/improvements: The applicability and the validity of the proposed method are evaluated in a case study. The case study is conducted in a pioneering digital online shopping company. The model is a decision aid for managers of the company to promote to a fast automation assembly system being able to provide product functions integrated to deliver customers’ desired products.

One of the key aspects of a project is to deliver the project on time and budget regardless of requirement, scope and time changes. Cost estimation has always been a difficult task in software development much of which is research is done on traditional cost estimation techniques but little is researched on agile methodologies.
Agile software development (ASD) provides a mechanism in reducing cost and time along with easy to handle ever-changing business environment and requirements. This study determines the impact of agile methodologies on cost estimation techniques in software development industry by focusing on different type of agile methodologies being used in software development industry. This study reveals how cost estimation at the beginning of each iteration helps company in making more easily and accurate estimate than traditional cost estimation techniques. The most common estimate technique is expert opinion a software development organization rely upon the expert in order to provide accurate estimate.
The use of agile methodologies in software development industry for cast estimation purposes is still very new concert. For this concert to be adopted on a larger scale future in-depth study on agile methodologies is required in order to measure exact impact on cost estimation.

One of the chief goals of the construction industry is to maintain a safe environment at construction sites, a goal best achieved by implementing Quality Management. Deming’s Total Quality Management (TQM) tools serve as an excellent option when it comes to efficiently using available resources to improve construction management at the site. Various accidents in the construction sites, however, may still occur, leading to loss of lives, delays and increasing project cost. Thus, an effective safety management system should be enforced to mitigate these accidents so as to reduce delay, cost and most importantly, prevent harmful accidents. A combination of TQM and Total Safety Management (TSM) ranks as one of the best available practices that establish a safe environment at the construction sites. In this paper, a survey has been designed, conducted and analyzed in order to solicit feedback from 61 engineers working in various construction companies and organizations in the UAE. Two construction processes that necessitate safety management are studied: safety of tower cranes and temporary formwork. The interrelationship between safety, quality, and reliability is also discussed along with the various causes of failure. The results of the survey reveal that the majority of the survey participants had implemented routine safety and health procedures to avoid accidents. The number of accidents, however, was still inordinately high due to top management pressurizing middle managers into completing construction goals within a designated time period.

Optimization of makespan in scheduling is a highly desirable research topic, deadlock detection and prevention is one of the fundamental issues. Supported by what learned from this class, a reinforcement learning approach is developed to unravel this optimization difficulty. By evaluating this RL model on forty classical non-buffer benchmarks and compare with other alternative algorithms, we presented a near-optimal result.

Quick advances in technology, challenges related to globalization such as increased economic warfare among developed countries, outsourcing and offshoring, and a global over qualified and multilingual workforce are increasing the competitiveness of businesses.
In order to succeed in the rapidly evolving global manufacturing landscape, companies will need to embrace a targeted approach to some of the key elements of manufacturing competitiveness, including Configuration Management.
Configuration Management has still a long way to evolve. This study reviews the current situation of the process of Configuration Management (CM) in such a competitive world. It focuses on one of the most important disciplines within CM, which is the Configuration Identification and more concretely the selection of CIs.
The contribution of this research is to explain: first, why CM has become more, rather than less, important in complex engineering in an era of globalization; and second, a review of the process to select the Configuration Items (CIs) which are key to manage the configuration of high tech engineering products. The investigation concludes by identifying the necessity of a scientific process for the CIs selection.

The chemical industrial processes with their energy-intensive production methods and unpleasant image have become “business as usual”. Polycarbonate (PC) is one example of energy intensive methods that has become one of the largest industrial processes. Moreover, a large number of hazardous chemicals are used throughout its manufacturing stages. This study is concerned with environmental aspects of PC production. It investigates life cycle based environmental performance evaluation of supercritical fluid (SCF) Application to PC production, more specifically in i) Environmental performance assessment of SFC as chlorinating alternative and ii) Environmental performance assessment of plasticizing scenario as stabilizing step in the PC production. The advantages of using SCF are tied to the cleaner aspects of the technology, minimisation of raw materials and energy demand, reduction of emissions and effluent discharge into the environment and maximisation of environmental benefits. Environmental performance of polycarbonates production by SCF was compared with that of traditional production methods. It was observed that supercritical fluid technology has an impact on the emissions reduction compared with traditional methods. This research contributes to understanding the challenges that the industry of polycarbonate production will face in the future where the chemical emissions are increased resulting from production and energy consumptions.