Исследование стоимости и трудоёмкости разработки программного обеспечения для решения задачи управления запасами предприятия

The article describes the process of estimating the cost and complexity of software development for the task of inventory management of a commercial enterprise to improve the decision-making process at the stage of formation of requirements for similar software products. There are different approaches to inventory management of a commercial enterprise. The algorithms implemented in the system are based on the constraint theory tool –dynamic inventory buffer management. Inventory management according to the theory of restrictions allows to provide a high level of availability of goods with minimal inventory in the system. After analyzing the subject area of inventory management and the methodology of dynamic inventory buffer management, a list of functional and non-functional software requirements was formed, and a data model was designed. The information obtained was used to compile a list of logical files and transactions specific to a particular requirement. From the resulting list of files and transactions, it is determined which elementary data, elementary records and links to files they consist of. The information obtained was used to estimate the size of the software at non-aligned functional points. To take into account the impact of non-functional requirements on the complexity of software development, the VAF alignment factor was calculated, for which it is necessary to give a qualitative assessment of the impact of system-wide requirements on the complexity of the software. The estimation of the complexity of the development was obtained using the COCOMO II methodology, namely, using seven multipliers of the complexity for the case of the initial assessment at the stage of approval of requirements. The calculations were obtained for teams with different professional level and equipment, in the conditions of a significant tightening of the development process, a high level of certainty of risks, without a rigid schedule of work. The cost of development was calculated for several common programming languages: J2EE, C#, C++.В статье описывается процесс оценки стоимости и трудоемкости разработки программного обеспечения задачи управления запасами торгового предприятия для улучшения процесса принятия решений на этапе формирования требований к аналогичным программным продуктам. Существуют различные подходы к управлению запасами торгового предприятия. Алгоритмы, реализованные в системе основаны на инструменте теории ограничений – динамическом управлении буфером запасов. Управление запасами по теории ограничений позволяет обеспечить высокий уровень наличия товара при минимальных запасах в системе. Проанализировав предметную область управления запасами и методологию динамического управления буфером товарных запасов был сформирован список функциональных и нефункциональных требований к программного обеспечения, а также спроектирована модель данных. Полученная информация была использована для составления перечня логических файлов и транзакций, характерных для конкретного требования. Из полученного списка файлов и транзакций определено, из каких элементарных данных, элементарных записей и ссылок на файлы они состоят. Полученная информация была использована для оценки размера программного обеспечения в не выровненных функциональных точках. Для учета влияния нефункциональных требований на трудоемкость разработки программного обеспечения был посчитан фактор выравнивания VAF, для чего необходимо дать качественную оценку влияния общесистемных требований на трудоемкость программного обеспечения. Оценка трудоемкости разработки была получена с использованием методологии COCOMO II, а именно с использованием семи множителей трудоемкости для случая первичной оценки на этапе утверждения требований. Расчеты были получены для команд с разным профессиональным уровнем и оборудованием, в условиях значительного ужесточения процесса разработки, высоким уровнем определенности рисков, без жесткого графика работ. Стоимость разработки была рассчитана для нескольких распространенных языков программирования: J2EE, C#, C++

Theory of constraints (TOC) production and manufacturing performance

This paper is based on an empirical study of the relationship between Theory of Constraints (TOC) production and operational performance in manufacturing plants. The study uses a survey questionnaire to collect data from a sample of 61 European firms which have implemented the TOC approach. Analysis of variance (ANOVA) technique and regression models have been employed to test the research hypotheses. The results detect many differences and similarities in adoption of TOC practices across the countries and suggest that manufacturing managers should consider adopting some TOC practices instead of others. In particular the Drum-buffer-rope methodology, the development of a Master Production Schedule based on constraints and the use of Non-constraint resources with excess capacity are among the most important practices to enhance competitive performance of manufacturing plants

Teaching operations management using a 'pseudo'-scientific approach

The purpose of this paper is to explore a theory led approach to teaching operations and supply chain management that has emerged from the analysis of seminal operations management developments and case research. This research identified common operations construct relationships encompassing variation, uncertainty, buffering mechanisms and trade-offs which are used to provide a common basis for explaining these developments, linking established theory with current professional practice. The construct relationships are further shown to comprise three distinct but coordinated strategies that provide a useful framework for case evaluatio

Managing the trade-off implications of global supply

The cost versus response trade-off is a growing logistics issue due to many markets being increasingly characterized by demand uncertainty and shorter product life cycles. This is exacerbated further with supply increasingly moving to low cost global sources. However, the poor response implications of global supply are often not addressed or even acknowledged when undertaking such decisions. Consequently, various practical approaches to minimising, postponing or otherwise managing the impact of the demand uncertainty are often only adopted retrospectively. Even though such generic solutions are documented through case examples we lack effective tools and concepts to support the proactive identification and resolution of such trade-offs. This paper reports on case-based theory building research, involving three cases from the UK and USA used in developing a conceptual model with associated tools, in support of such a process

Unified Concept of Bottleneck

The term `bottleneck` has been extensively used in operations management literature. Management paradigms like the Theory of Constraints focus on the identification and exploitation of bottlenecks. Yet, we show that the term has not been rigorously defined. We provide a classification of bottleneck definitions available in literature and discuss several myths associated with the concept of bottleneck. The apparent diversity of definitions raises the question whether it is possible to have a single bottleneck definition which has as much applicability in high variety job shops as in mass production environments. The key to the formulation of an unified concept of bottleneck lies in relating the concept of bottleneck to the concept of shadow price of resources. We propose an universally applicable bottleneck definition based on the concept of average shadow price. We discuss the procedure for determination of bottleneck values for diverse production environments. The Law of Diminishing Returns is shown to be a sufficient but not necessary condition for the equivalence of the average and the marginal shadow price. The equivalence of these two prices is proved for several environments. Bottleneck identification is the first step in resource acquisition decisions faced by managers. The definition of bottleneck presented in the paper has the potential to not only reduce ambiguity regarding the meaning of the term but also open a new window to the formulation and analysis of a rich set of problems faced by managers.

Manufacturing Processes Management with Usage of Simulation Tools

Simulace výrobních procesů pomáhá optimalizovat výrobu, logistiku a další systémy, díky čemuž dochází ke snižování nákladů a racionalizaci vnitropodnikových procesů. Využitím diskrétní simulace programu Witness Power with Ease se v diplomové práci optimalizuje logistický tok materiálu ve společnosti Hella Autotechnik, s.r.o. Práce přibližuje metody a jednotlivé fáze tvorby modelu včetně jeho validace a navrhuje vylepšení, díky kterému by mělo dojít ke snížení nákladů na dopravní služby o 24 400 Kč měsíčně.By optimizing the logistics, production and other systems the simulation can reduce costs and rationalise business processes. By use of discrete simulation in software Witness Power with Ease is in this diploma thesis optimised logistical flow of material in the company Hella Autotechnik, s.r.o. The thesis introduces methods and particular phases of creating the model including its validation. The proposal in the diploma work suggests the improvement to lower the costs for the transportation services by 24,400 CZK per month.

A practical approach to achieving agility : a theory of constraints perspective

This article documents an action research (AR) project aimed at identifying the practical steps needed to become an agile manufacturer through a combination of the theory of constraints (TOC) and resource- based view (RBV) approaches in a small to medium enterprise (SME) in the Australian manufacturing sector. To date, lean production has been highlighted as a possible catalyst for creating an agile manufacturer, despite the evidence suggesting that lean manufacturing lacks the responsiveness and adaptability to effectively handle a rapidly changing market place and only works well in a stable environment. A more flexible system of production is required to fully encompass the agile characteristics needed to attain a competitive advantage. This research provides empirical evidence that the TOC perspective can be used as a practical approach for becoming an agile manufacturer. The study provides a workable approach for small firms to achieve ‘Agility’ in practice

Outcome evaluation of research for development work conducted in Ghana and Sri Lanka under the Resource, Recovery and Reuse (RRR) subprogram of the CGIAR Research Program on Water, Land and Ecosystems (WLE).

This is the main report of an external evaluation of the Resource Recovery and Reuse Flagship of the Water Land and Ecosystems (WLE) CGIAR Research Program. WLE commissioned the study. The Evaluators interviewed researchers and partners in two countries, Ghana and Sri Lanka, and in Ghana visited two sites. They also interviewed key international partners and analyzed a wide range of documents, reports and publications. The evaluation was focused on understanding how and in what ways the research and other activities carried out by IWMI and supported by WLE contributed to the outcomes. In essence, the purpose was to understand the specific impact pathways from research to outputs and outcomes

Integrating a Procurement Management Process into Critical Chain Project Management (CCPM): A Case-Study on Oil and Gas Projects, the Piping Process

Engineering, Procurement, and Construction (EPC) of oil and gas megaprojects often experience cost overruns due to substantial schedule delays. One of the greatest causes of these overruns is the mismanagement of the project schedule, with the piping works (prefabrication and installation) occupying a majority of that schedule. As such, an effective methodology for scheduling, planning, and controlling of piping activities is essential for project success. To meet this need, this study used the Critical Chain Project Management (CCPM) to develop a piping construction delay prevention methodology, incorporating material procurement processes for EPC megaprojects. Recent studies indicate that the traditional scheduling method used on oil and gas mega projects has critical limitations regarding resource scarcity, calculation of activity duration, and dealing with uncertainties. To overcome these limitations, the Theory of Constraints-based CCPM was proposed and implemented to provide schedule buffers management. Nonexistent in literature, and of critical importance, is this paper's focus on the resource buffer, representing material uncertainty and management. Furthermore, this paper presents a step-by-step process and flow chart for project, construction, and material managers to effectively manage a resource buffer through the CCPM process. This study extends the knowledge of traditional resource buffers in CCPM to improve material and procurement management, thus avoiding the shortage of piping materials and minimizing delays. The resultant process was validated by both deterministic and probabilistic schedule analysis through two case studies of a crude pump unit and propylene compressor installation at a Middle Eastern Refinery Plant Installation. The results show that the CCPM method effectively handles uncertainty, reducing the duration of piping works construction by about a 35% when compared to the traditional method. Furthermore, the results show that, in not considering material uncertainty (resource buffers), projects schedules have the potential for approximately a 5% schedule growth with the accompanying delay charges. The findings have far-reaching applications for both oil and gas and other sectors. This CCPM case-study exemplifies that the material management method represents an opportunity for industry to administrate pipeline installation projects more effectively, eliminate project duration extension, develop schedule-based risk mitigation measures pre-construction, and enable project teams to efficiently manage limited human and material resources.111sciessciscopu

Critical chain construction with multi-resource constraints based on portfolio technology in South-to-North Water Diversion Project

AbstractRecently, the critical chain study has become a hot issue in the project management research field. The construction of the critical chain with multi-resource constraints is a new research subject. According to the system analysis theory and project portfolio theory, this paper discusses the creation of project portfolios based on the similarity principle and gives the definition of priority in multi-resource allocation based on quantitative analysis. A model with multi-resource constraints, which can be applied to the critical chain construction of the A-bid section in the South-to-North Water Diversion Project, was proposed. Contrast analysis with the comprehensive treatment construction method and aggressive treatment construction method was carried out. This paper also makes suggestions for further research directions and subjects, which will be useful in improving the theories in relevant research fields