scholarly journals Evaluation of the Impact of Dynamic Work Stations Versus Static Work Stations in Wood Framing Prefabrication using Hybrid Simulation

Author(s):  
Beda Barkokebas ◽  
Samer Bu Hamdan ◽  
Aladdin Alwisy ◽  
Mohamed Al-Hussein

Offsite manufacturing has introduced significant improvements in terms of both time and cost savings to the construction industry. The fabrication of modular units and construction components in factories has permitted the reshaping of the traditional stick-built process. By reallocating the majority of onsite activities to offsite facilities, onsite preparation tasks can be performed concurrently to the offsite production. The success of offsite manufacturing relies on the efficiency of the factory’s production line. Continuous workflow improves factory efficiencies by reducing or eliminating fluctuations and bottlenecks among work stations. Imbalance in the production line is a result of work station capacity errors and other conditions unique to the construction industry. Unlike other industries, construction projects are often customized and have lower repetition quantities. The variations in the modular units or components being produced poses a challenge in balancing traditional work stations along the production line due to continuous changes in complexity level, which in turn affects productivity. This research proposes the use of dynamic work stations along with traditional ones, using multi-skilled workers relocating among specific work stations in response to product complexity levels. Two approaches are evaluated in order to balance the production line: (1) increase number of workers in static work stations; and (2) use dynamic work stations. A production comparison is performed using a hybrid simulation model, combining discrete-event and continuous simulation. The plotted results identify the optimum number of workers in the two stations, static versus dynamic, to meet demand. The model is validated and is found to achieve a reduction of 18.68% and 32.00% in the total production time for two different scenarios without increasing the original number of workers.

2015 ◽  
Vol 3 (2) ◽  
pp. 69-84
Author(s):  
Wadhah Amer Hatem ◽  
Samiaah M. Hassen Al-Tmeemy

     Suicide attacks, bombings, explosions became the part of daily life in Iraq. Consequently, the threat of terrorism put the Iraqi construction sector in the face of unique and unusual challenges that not seen on other countries. These challenges can have extensive impact on construction projects. This paper seeks to examine the impact of the terrorist attacks on construction industry and determine the extent to which the impact of terrorism on construction projects in terms of cost, schedule, and quality. This study adapted quantitative and qualitative approaches to collect data using questionnaire survey and interviews, as well as historical data. The study focused on projects that have been the target of terrorist strikes in Diyala governorate. A variety of statistical procedures were employed in data analysis. The results revealed the extent to which terrorist attacks impact construction projects in terms of cost, time, and quality. The results of this study will enhance the awareness of all construction parties to the impact of the terrorist attacks against construction projects. Eventually, this can develop a risk management assessment and assist contractors to properly protect projects and buildings to minimize injuries and fatalities in the event of terrorism.


Author(s):  
V.V. Verna

The article provides a rationale for methodological approaches to assessing the effectiveness of outsourcing in organizations of the construction industry using the example of outsourcing schemes to perform personnel functions. The conditional example shows the impact of the use of outsourcing on reducing the costs of a construction organization. The main prerequisites for the use of outsourcing in the activities of enterprises in the construction industry are identified, methodological approaches to assessing the cost-effectiveness of personnel outsourcing in the construction industry enterprises are substantiated.


2019 ◽  
Vol 11 (3) ◽  
pp. 926 ◽  
Author(s):  
Gui Ye ◽  
Yuhe Wang ◽  
Yuxin Zhang ◽  
Liming Wang ◽  
Houli Xie ◽  
...  

Total factor productivity (TFP) is of critical importance to the sustainable development of construction industry. This paper presents an analysis on the impact of migrant workers on TFP in Chinese construction sector. Interestingly, Solow Residual Approach is applied to conduct the analysis through comparing two scenarios, namely the scenario without considering migrant workers (Scenario A) and the scenario with including migrant workers (Scenario B). The data are collected from the China Statistical Yearbook on Construction and Chinese Annual Report on Migrant Workers for the period of 2008–2015. The results indicate that migrant workers have a significant impact on TFP, during the surveyed period they improved TFP by 10.42% in total and promoted the annual average TFP growth by 0.96%. Hence, it can be seen that the impact of migrant workers on TFP is very significant, whilst the main reason for such impact is believed to be the improvement of migrant workers’ quality obtained mainly throughout learning by doing.


2021 ◽  
Vol 13 (7) ◽  
pp. 3591
Author(s):  
Marija Mosurović Ružičić ◽  
Mirjana Miletić ◽  
Marina Dobrota

Influences from the modern business environment indicate the need for the incorporation of sustainability concepts from an innovation system perspective. In the presented research, we emphasize the energy efficiency concept within the frame of sustainability and innovation. The aim of this research was to underline and explore the relationships between innovation, energy efficiency, and sustainability in the construction industry. To answer the research questions, a questionnaire was created to explore the impact of the energy efficiency certification process on the innovation behavior of construction industry enterprises in Serbia. The results show that energy efficiency has supported innovation, and that there exists a relationship between sustainability and innovativeness in the construction industry. Applying energy efficiency passports has influenced the co-operation of enterprises in the construction sector and other actors in the national innovation system in Serbia. The innovation concept demonstrates that enterprises in the construction industry should be observed as a part of the wider picture—the national innovation system. In turn, the specific context of a particular national innovation system should be seen within the wider picture of national innovation systems of Central and Eastern European Countries (CEECs).


2021 ◽  
pp. 0734242X2098206
Author(s):  
Haijun Bi ◽  
Huabing Zhu ◽  
Jialin Zhan ◽  
Lei Zu ◽  
Yuxuan Bai ◽  
...  

Lithium iron phosphate (LFP) batteries contain metals, toxic electrolytes, organic chemicals and plastics that can lead to serious safety and environmental problems when they are improperly disposed of. The published literature on recovering spent LFP batteries mainly focuses on policy-making and conceptual design. The production line of recovering spent LFP batteries and its detailed operation are rarely reported. A set of automatic line without negative impact to the environment for recycling spent LFP batteries at industrial scale was investigated in this study. It includes crushing, pneumatic separation, sieving, and poison gas treatment processes. The optimum retaining time of materials in the crusher is 3 minutes. The release rate is the highest when the load of the impact crusher is 800 g. An air current separator (ACS) was designed to separate LFP from aluminium (Al) foil and LFP powder mixture. Movement behaviour of LFP powder and Al foil in the ACS were analysed, and the optimized operation parameter (35.46 m/s) of air current speed was obtained through theoretical analysis and experiments. The weight contents of an Al foil powder collector from vibrating screen-3 and LFP powder collector from bag-type dust collector are approximately 38.7% and 52.4%, respectively. The economic cost of full manual dismantling is higher than the recovery production line. This recycling system provides a feasible method for recycling spent LFP batteries.


2021 ◽  
Vol 13 (11) ◽  
pp. 5956
Author(s):  
Jelena Končar ◽  
Radenko Marić ◽  
Goran Vukmirović ◽  
Sonja Vučenović

This work aims to define the impact of different indicators on the sustainability of food placement in the retail sector, during periods of crisis and emergencies, such as the COVID-19 pandemic. An empirical survey conducted in the Western Balkans (WB) region showed that indicators such as developed infrastructure, consistency, and transparency of the supply chain, skilled workers, costs, food safety, food prices, energy consumption, and changes in consumer needs are statistically significant since they affect the sustainability of food placement in the retail sector. As food placement and the retail sector itself are inseparable from other participants in the food supply chain (FSC), an analysis was conducted at the level of all FSC sectors. The results showed some deviations viewed individually in the sectors of production, physical distribution, wholesale, and retail, and in selected Western Balkan countries. Based on the results obtained, the sustainability model of food placement in the retail sector has been defined. The model will serve as the basis for defining the set of measures and incentives that competent institutions and FSC management need to undertake, to minimize the impact of indicators that endanger sustainability. The originality of the study lies in the fact that it fills the research gap that exists in this subject matter in academic research and studies in the WB region. In addition, some indicators important for food placement have been precisely isolated, with the definition of the intensity of their impact, observed overall at the level of the entire FSC as well as by individual sectors. Guidelines and suggestions for future research are listed in the paper.


2016 ◽  
Vol 43 (2) ◽  
pp. 336-356 ◽  
Author(s):  
Franklin Amuakwa-Mensah ◽  
Louis Boakye-Yiadom ◽  
William Baah-Boateng

Purpose – The purpose of this paper is to investigate the effect of education on migration decisions focusing on rural and urban in-migrants by comparing the 2005/2006 and 2012/2013 rounds of the Ghana Living Standards Survey (GLSS5 and GLSS6). After correcting for selectivity bias, the authors observed that anticipated welfare gain and socio-economic variables such as sector of employment, sex, experience, age, educational level and marital status significantly affect an individual’s migration decision. Design/methodology/approach – The authors made use of Sjaastad’s (1962) human capital framework as a basis for examining the impact of education on migration. The migration decision equation was based on the Heckman two stage procedure. Findings – While educational attainment is observed to have a positive effect on migration decision in the period 2005/2006, the authors find a negative effect of educational attainment on migration decision in the period 2012/2013. The effect of educational attainment on migration decision in 2005/2006 for urban in-migrant is higher than the effect for rural in-migrant, with its significance varying for the different stages of educational attainment. In absolute terms, whereas the effect of secondary educational attainment on migration decisions for urban in-migrant is higher than that of rural in-migrant, the reverse holds for higher educational attainment during the period 2012/2013. Social implications – Based on the mixed effect of education on migration decision as evident from the study, policies to enhance the educational system in Ghana should be complemented with job creations in the entire country. Moreover, special attention should be given to the rural sector in such a way that the jobs to be created in the sector do not require skilled workers. With quality education and job creation, the welfare of individuals living in urban and rural areas will be enhanced. Originality/value – In spite of the importance of education in migration decisions, there is scanty literature on the rural-urban dimension. To the best of the author’s knowledge there is no literature in the Ghanaian context which examines the rural and urban perspective of the impact of education on migration with a much recent data. Further, the author consider how the determinants of migration decision have changed over time focusing on rural and urban perspectives.


1998 ◽  
Vol 166 ◽  
pp. 78-86 ◽  
Author(s):  
Bob Anderton ◽  
Paul Brenton

The US experienced a considerable increase in inequality between skilled and less-skilled workers during the early 1980s—a period which corresponds with a large temporary appreciation of the dollar. This article investigates the reasons behind this rise in inequality by evaluating the impact of trade with low-wage countries (LWCs) and technological change on the wage bill share of skilled workers (which is designed to capture movements in inequality arising from changes in both the relative wage and employment opportunities of the less-skilled). We find that an increase in US imports from LWCs—encouraged by the large appreciation of the dollar in the early 1980s—seems to explain some of the rise in US inequality in low-skill-intensive sectors, but that technological change (proxied by R&D expenditure) explains the rise in inequality in high-skill-intensive sectors. However, given that the timing of the sudden rise in US R&D expenditure corresponds with the appreciation of the dollar, it may be the case that the deterioration in US trade competitiveness during this period contributed to the rapid increase in the rate of technological change via mechanisms such as ‘defensive innovation’. Hence one might also argue that the technology-based explanation for the rise in US inequality could actually be a trade-based explanation.


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