Relationships between System Loading and Cycle Time in a Residential Construction Production System

Production home building possesses characteristics similar to manufacturing processes, such as the construction of more or less similar houses repeatedly and a growing demand for mass customization of homes. As a result of these similarities, larger homebuilders often attempt to view their production system as an assembly line process. However, the management tools generally utilized by these home builders are those used in other sectors of the construction industry, such as critical path method scheduling, cost estimating, and earned value analysis. These management tools do not provide an explanation or control/prediction tools for many undesirable situations that arise during home building, such as increasing cycle time which slows delivery of product to consumers and increases project capital costs, and increasing amounts of work in process that increases capital investment and thereby decreases company financial performance. In order to bring better management tools to the residential construction in...

Even though the construction management (CM) system was introduced for the purpose of increasing the efficiency of the domestic construction industry along with the establishment of construction industry fundamental laws in December of 1996, now it is very difficult that the public institutions can judge their application of construction management methods due to the lack of clear guidelines or directions to select construction management methods when the public institutions were executing public construction projects. Therefore, this study was executed to prepare for the selection criteria which could be referred in reviewing the application of construction management ordering methods according to public institution`s competences and project characteristics. It is expected that future domestic demand of construction management will be gradually increasing both in public and private construction sectors. However under the current construction management systems, it is judged to be difficult that the construction projects that apply the construction management methods will be activated with full-scale. Therefore, it could be said that active efforts in domestic sectors are required in order that the construction management systems of developed countries levels could be activated. Additionally in order to vitalize the construction management systems, it is expected that public institutions could use this study results as the review data for feasibility of construction projects for the consignment of construction management in selecting the ordering methods.

Investigation of temperature effects from LCO2 with different cycle parameters on the coal pore variation based on infrared thermal imagery and low-field nuclear magnetic resonance

Integrated processing tools are becoming increasingly prevalent in modern fabs. Integrated tools consist of several process modules connected around a central handler such that the modules can process several wafers from the same lot simultaneously. Lithography cells and vacuum cluster tools are examples of integrated processors. Simple, intuitive models of the cycle time, throughput, and wafer cost of integrated tools are introduced. The models use two measurable parameters that aggregate tool operations: the incremental cycle time is the average increase in cycle time resulting from a lot size increment of one wafer and the fixed cycle time is the portion of cycle time that is independent of lot size. One example shows how an empirical analysis of a commercial CVD cluster tool was used with the models to identify opportunities to increase tool throughput. In a second example, analytical models of the incremental and fixed cycle times are used to provide insight into the effects of tool configuration on performance. Finally, simulations of single integrated tools are used to show some limitations of the model.

In the present work, an industrial-scale experiment on ventilation air methane (VAM) utilization by a multibed thermal flow-reversal reactor (TFRR) is conducted in China. The influence of the inlet flow rate, feed methane concentration, and cycle time on the temperature distribution of the bed and heat recovery efficiency are investigated. The methane conversion in the studied cases exceeds 97%. The results show that the methane concentration during self-maintained operation of the TFRR without heat recovery should not be less than 0.22 vol % when the inlet flow rate is 103,000 Nm3/h and the cycle time is 300 s. As the inlet flow rate decreases, the lower concentration limit of automatic thermal maintenance increases. The peak temperature of the bed approaches the inlet side as the feed methane concentration increases and the cycle time decreases. The heat recovery efficiency increases linearly with increasing inlet flow rate, rises parabolically with an increasing feed methane concentration, and decreases weakly with increasing cycle time.

Phenotypic relationships between maternal energy metabolism and lamb body weight development during lactation for pure- and crossbred sheep populations in low and high input production systems

Production systems literature usually attributes throughput losses to two reasons: unreliable equipment and random part processing time (also referred to as machine cycle time). In practice, however, one more reason for throughput losses is observed: cycle overrun. The specificity of cycle overrun is that not all parts may require more time than allotted by a fixed cycle time and, if the overrun does occur, its duration is coupled with the part processing time: typically, it is a fraction or a small multiple of the cycle time. This paper is indented to develop methods for analysis and improvement of production systems with unreliable machines and cycle overrun. Specifically, it introduces a mathematical model of an unreliable machine with cycle overrun, develops its simplified version, explores the efficacy of machines' improvability by reducing either downtime or cycle overrun, and discusses the issue of bottleneck identification. These results are obtained under the exponential assumption on machine reliability and overruns and then extended to the non-exponential case. Finally, the methods developed are illustrated by a case study based on an automotive transmission case machining line.

This chapter explores manufacturing in the smart city, and presents a framework that integrates distributed manufacturing with smart city technologies (such as big data and the industrial Internet of Things (IIoT)). This framework aims to explore the interplay of smart city technology with production organization and design. The following are the interplay of smart city technologies with four production system characteristics: network design, manufacturing, distribution, and service. The chapter builds on the post-Fordist and Toyota Production System (TPS) production system paradigms to focus on the development of the smart city production system. This is identified in the matrix and has been characterized by flexible and low scale production runs. There are low levels of inventory as the point of production is located close to consumption points and within city boundaries (local production).

Most forest harvesting operations are performed using two or more forestry machines in combination; in the typical forest production system in steep terrain in Japan, there are four production processes: felling, yarding, processing, and forwarding. It is essential to evaluate the overall productivity of such combined production systems, but the calculation method that indicates the productivity has not been fully established. In this study, we built simulation models of serial, parallel, and sequential production systems by using system dynamics to evaluate their productivity regarding the combined machine productivity (CMP) and combined labor productivity (CLP) indices. Comparing the three types of forest harvesting systems in Japan, the parallel production system had the highest CMP, while the serial production system had the highest CLP; the sequential production system lay between the serial and parallel production systems in terms of CMP and CLP. The overall productivity of Japanese forest production systems was lower than that of Central Europe, where processor tower yarders (PTYs) are used. Thus, the CLP of Japanese forest production systems was improved by 12.8 to 26.5% by incorporating the concept of a PTY, and it can be further improved by eliminating the forwarding process.

Although still in its early stages for the average manufacturing firm, the adoption of digital technologies has arrived in production systems. In response to these changes, firms are transforming their production systems and processes to accommodate this trend towards digitalization, constituting Industry 4.0. To make change effective, manufacturing firms are implementing advance production technologies and complement these with the necessary organizational changes in the production processes. Building on the premises of diffusion of innovation theory, the resource-based view and socio-technical systems theory, the present study examines whether the relation between the implementation of digital technologies and flexibility- and quality-enhancing organizational practices have a direct and moderating effect on the operational efficiency of manufacturing firms. The data come from a questionnaire-survey among 502 Spanish and Dutch organizations that responded to the European Manufacturing Survey in 2015 and 2018. Using a concatenated and multi-country dataset, the results reveal that both digitalization and organizational practices affect operational efficiency positively, but the impacts are mostly on different efficiencies, i.e. digitalization results in more efficiency regarding quality aspects (scrap rate, quality complaints), while organizational practices impact lead time and not-on-time-delivery efficiencies, and quality complaints. Both technologies and flexibility- and quality-enhancing organizational practices are seemingly needed, and sometimes even complement each other, but they do not provide synergy effects in combination. Last, early adoption of the digital technologies can help to further improve operational efficiencies.

The integration of on-product diffraction-based focus (DBF) capability into the majority of immersion lithography layers in leading edge logic manufacturing has enabled new applications targeted towards improving cycle time and yield. A CD-based detection method is the process of record (POR) for excursion detection. The drawback of this method is increased cycle time and limited sampling due to CD-SEM metrology capacity constraints. The DBFbased method allows the addition of focus metrology samples to the existing overlay measurements on the integrated metrology (IM) system. The result enables the addition of measured focus to the SPC system, allowing a faster excursion detection method. For focus targeting, the current method involves using a dedicated focus-exposure matrix (FEM) on all scanners, resulting in lengthy analysis times and uncertainty in the best focus. The DBF method allows the measurement to occur on the IM system, on a regular production wafer, and at the same time as the exposure. This results in a cycle time gain as well as a less subjective determination of best focus. A third application aims to use the novel onproduct focus metrology data in order to apply per-exposure focus corrections to the scanner. These corrections are particularly effective at the edge of the wafer, where systematic layer-dependent effects can be removed using DBFbased scanner feedback. This paper will discuss the development of a methodology to accomplish each of these applications in a high-volume production environment. The new focus metrology method, sampling schemes, feedback mechanisms and analysis methods lead to improved focus control, as well as earlier detection of failures.

General structure and characteristics of quick response production system

The standard documents of the American Institute of Architects and the Associated General Contractors of America for construction management projects imply processes and operational procedures that have become customary if not standard since publication in 1975. Adjustments must be made to accommodate the particular form and variation of construction management specifically required by the contract. However, construction management firms have a tendency to customize processes and procedures for their own convenience. This is especially true on projects where a firm is contractually assigned other service responsibilities such as design, contracting, or construction. When a CM process and its procedures exactly match the intent of the project delivery system, owners are positioned to gain from the use of the system. When convenience intervenes, the system cannot function effectively, and the owner may experience negative results. This paper argues that convenient customizing of the CM process and its procedures, especially customizing that mitigates the checks and balances specifically built into the construction management system and implied by established CM practice, represents a detrimental divergence from the fundamental reasons CM is. selected for use by owners on their projects.

The aim of this paper is to present a study that deals with the problem of oversized boulders in a mine production system. This work was performed to study and analyze the disturbances caused by oversized boulders and estimate their impact on the production system at the LKAB Kiruna Iron Ore Mine, Kiruna (KIOM). The results from this study show that by elimination of oversized boulders from the production process, the production capacity and system utilization of a mine like KIOM can be considerably improved.

Industry has undertaken mass production and consumed resources to optimize only economic efficiency. Most products are discarded or disposed at the end of their lifetimes. Therefore, most companies should design and manage their production system for sustainability. One of the most important factors to develop a sustainable production system is the environmental aspect. Environmentally conscious operations management makes some contributions to sustainable development goals (SDGs) #9 and #12. This chapter deals with production and quality management systems for SDGs. Firstly, representative operations management systems such as inventory management and total quality management (TQM) are introduced. These systems are useful to control the production processes efficiently. Secondly, we explain the Just-in-Time (JIT) production system which is based on the two key concepts, JIT and JIDOKA. Some advantages of the JIT production system include its simplicity in production scheduling, reduced burden on operators, ease of identification of parts by the two kinds of kanbans attached to the containers, and substantial reduction in the process work. Finally, we consider environmentally conscious manufacturing and describe a closed loop supply chain which includes activities necessary to acquire end-of-life products from customers to recover value.