Evolutionary optimization of Haferman carpet fractal patterned antenna array

This article investigates radiation characteristics of a new type of fractal shaped antenna array based on Haferman carpet geometry. An iterative feed matrix eases the complexity of array factor calculation that makes the array factor suitable for the application of any evolutionary optimization techniques. It is seen that Haferman carpet array produces peak side lobe level (PSLL) better than Sierpinski carpet that produces ?10 dB PSLL at every stage of growth. Optimization techniques have been applied for array element reduction and PSLL minimization at different stages of growth. Here, PSLL is minimized by turning off array elements and also by varying inter element spacing between the array elements. The optimized version of Haferman carpet array produces better characteristics (49.38% thinning with ?20.5 dB PSLL for stage‐2, 46.3% thinning with ?22 dB PSLL for stage‐3 and 42.3% thinning with ?21dB PSLL for stage‐4) than its original counterpart in terms of reduced element count and PSLL. Numerical results for obtaining optimized array performance exploit both DE as well as PSO. A comparative study on the performance is also presented. As a whole, Haferman carpet is seen to be more effective approach than Sierpinski carpet in fractal antenna paradigm. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:719–729, 2015.     

Stand up: comparison of two electrical screed levelling machines to reduce the work demands for the knees and low back among floor layers

Electrical screed levelling machines are developed to reduce kneeling and trunk flexion of sand–cement-bound screed floor layers. An observational intervention study among 10 floor layers was performed to assess the differences between a self-propelled and a manually moved machine. The outcome measures were work demands, production time, perceived load, discomfort and applicability. Compared to the self-propelled machine, the duration of kneeling (?13 min; p = 0.003) and trunk flexion (?12 min; p < 0.001) was shorter using the manually moved machine, and the duration of pushing and pulling increased (?39 min; p < 0.001). No significant or relevant differences were found for production time, perceived load and discomfort. Nine out of ten floor layers found the manually moved machine applicable and three out of ten found the self-propelled machine applicable. When compared with the traditional manner of floor laying, both electrical machines reduced the exposure towards kneeling and trunk flexion.

Practitioner Summary: Electrical machines may help to reduce high physical work demands on floor layers. A manually moved machine is better applicable for the installation of screed floors in residences with smaller floor areas. A self-propelled machine is better applicable on large floor areas with a minimum width of 4 m.     

Revision and validation of the Connor-Davidson Resilience Scale of coal miners in China

The psychological state of coal miners may have negative changes because of the long-term underground working environment and complex production process and will cause unsafe behaviour. Resilience can enhance the adaptability of individuals to high-risk and high-pressure environments and predict unsafe behaviour. However, currently little research has been done to develop resilience measuring tools for coal miners. Therefore, this paper revised and verified the Connor-Davidson Resilience Scale (CD-RISC) among coal miners in China and developed an individual resilience scale available for the coal industry. Five hundred and twenty subject coal miners have finished the initial test, and the exploratory factor analysis and reliability analysis were used to revise the CD-RISC. Another survey on 639 samples was then conducted to assess a confirmatory factor analysis and test-retest reliability of the resilience scale. The resulting scale has two dimensions, tenacity and strength, including a collection of 6 items. This study assists in further exploring the structural factor of individual resilience level for China coal industry, and provides a new research idea for occupational health, and contributes to the safety management and sustainable development of the coal enterprises.     

Application of multiple‐response optimization methods for the ergonomic evaluation of carpet weaving knife

The aim of this study is to evaluate several weaving knife configurations in response to multiple criteria’s for optimum design. Nine different knife combinations were tested over ten female weavers in a field experiment. Three levels of blade width and angular orientations were taken as the independent variables. Output response about goniometry and electromyography were taken as dependent variables. Multivariate analysis was carried out to estimate the effect of independent variables on output responses. To tackle the difficulty of knife selection with several output responses, three multicriteria optimization approaches have been compared. Multivariate analysis of variance results showed that the effect of both blade width and angle were significant at wrist angles. Also, the magnitude of effect size on both blade width and the angle was highest for the wrist angles. Despite the same weighing criteria, a slight difference was evident between the ranks from optimization methods. The higher blade widths and smaller angular orientations should be recommended for reduction of wrist deviation and muscle activity during weaving. The best possible combination of knife evaluated using multicriteria optimization was 25 mm × 100°.     

A BIM-based simulation framework for fire safety management and investigation of the critical factors affecting human evacuation performance

Fire hazards are a big threat to human life and property safety. The U.S. fire statistics reveal that, in 2017 alone, 1,319,500 fires caused 3400 deaths and 14,670 injuries, which resulted in a loss of $23 billion [1]. Effective evacuation planning in densely occupied buildings should be primarily put in place if both the number of injuries/fatalities and the level of property loss are to be minimized. However, it is not realistic, and is unethical to study human evacuation performance under a burning building. For this reason, computational tools tend to be the best approach for simulating fire growth as well as human response to fire hazards. This study aims to develop a BIM-based simulation framework that implements the Fire Dynamic Simulator (FDS) and agent-based modeling (ABM) for simulating fire growth and evacuation performance for different building layout scenarios. An experimental implementation is conducted to validate the proposed framework, which verified the benefits of (1) using BIM to offer a platform for conducting simulation design and visualizing the simulation results of (a) hazardous fire zones and (b) effective escape routes; (2) simulating fire growth using the FDS tool; (3) developing an agent-based model that accounts for the critical factors affecting evacuation performance; and (4) applying a statistical analysis for investigating the effects of influential parameters from the proposed model. As a result, the simulation outputs can be used to optimize the building design and to investigate the influential factors on human evacuation efficiency. The proposed framework contributes to building fire safety management by enabling to minimize both injuries/fatalities and property loss.     

From industrial safety to corporate health management

Occupational health and safety is one of the most important topics of ergonomics. In many countries the practical issues are addressed in worker protection laws or rules and most companies have some sort of occupational health and safety system. As with many other ergonomics approaches, such activities are often necessary because of legal requirements. Such efforts are often viewed by management as primarily cost intensive. To change this image, it would be helpful to have a more positive, management-oriented approach. Corporate health management as a module of an integrated management system can fulfil this goal.     

Exploring the factors affecting global manufacturing performance*

ABSTRACT

A decision tree is used to explore the effects of Information and Communication Technologies (ICTs) and financial factors on global manufacturing industry sales performance. Existing research provides an unclear picture of how ICTs affect sales performance. Earlier studies showed little evidence that ICTs improve performance, more recent studies do. Our investigation found that between 2006 and 2009, companies with high ICT scores performed well, but their performance declined substantially between 2010 and 2014. ICTs do not significantly influence manufacturing sales growth performance, but financial factors do. Supplier credit as a source of financing leads to negative sales growth, while low loan collateral improves sales performance. Taking advantage of bank financing improves sales, but using equity or stocks to fund investments negatively affects them. These findings are used to develop seven research hypotheses for future studies.     

Some factors affecting elementary teachers' use of the computer

A survey of 70 fourth and fifth grade elementary teachers revealed several interesting factors, not documented elsewhere, that affect teachers' use of the computer. First, very few teachers themselves owned computers or used them for personal reasons at home or school. Second, most teachers felt that neither they nor the students should be held accountable for the teaching or learning of computer objectives. Third, teachers were perplexed as to how to manage students who were not able to take their turn on the computer. Fourth, several teachers chose not to use district-provided sources written to help them implement the computer. Fifth, most teachers had little understanding of the scope and sequence of the district's computer curriculum and how their grade level fit into this. Sixth, most teachers felt that they were allotted too little time to teach computers each week.     

软件可靠性影响因素权重分析

对软件可靠性早期预测模型的研究,首先必须考虑影响软件可靠性的主要因素。而影响因素权重的确定可以说是整个早期预测模型的“灵魂”。针对主观赋权法和客观赋权法的优缺点,提出了基于神经网络和MIV的组合赋权法来分析软件可靠性的影响因素。该方法首先根据主观赋权法得到影响因素的排序,然后利用神经网络的强大的非线性处理能力以及MIV进行客观分析,从而获得更客观更具解释性的权重值和排序。     

Bernardino Ramazzini's early observations of the link between musculoskeletal disorders and ergonomic factors

Bernardino Ramazzini (1633-1714) systematically studied the relationship between work and diseases. He realized that it was not possible to ascribe all workers' diseases to chemicals or physical agents and foresaw that other factors were involved. He observed that common diseases could originate following the maintenance either of prolonged stationary postures or of unnatural postures (e.g. bakers, workers who stand, sedentary worker, scribes, weavers) or following activities requiring heavy muscular performance (e.g. porters and woodworkers). Furthermore, Ramazzini recognized the need to undertake measures to prevent disorders from repetitive motions and manual lifting and anticipated the now accepted advice of moderation and recommendations of reduction of work duration for a number of hard jobs requiring a standing position or severe muscular effort. From his early writings therefore it is evident that Ramazzini realized the importance of assessing the ergonomic factors associated with the occurrence of work-related musculoskeletal disorders.     

Implementation programme of the Swedish ordinance concerning work postures and working movements

Ergonomically-rclated occupational injuries have been increasingly recognized in Sweden. The official injury statistics show that ergonomically-related injuries accounted for about 20% of all reported occupational injuries (ISA 1985). On 1 January 1984 an ordinance concerning work postures and working movements was passed. It was built upon and is a complement to the Work Environment Act of 1978. There are in Sweden about 400 labour inspectors in 19 regional Labour Inspectorates, to ensure among other things that rules concerning the occupational environment are complied with at the workplace level. Sweden has a working population of about 4 million people. To implement the above-mentioned ordinance, a 2-year implementation programme was set up. The labour inspectors first identified major areas with severe non-ergonomic working conditions, in all areas of work. Six typical work situations were then selected and the inspectors were asked to pay special attention to them, and to intensify their efforts on these work situations, during a 10-month period. Eighteen months after the ordinance came into effect, the implementation programme and the labour inspectorate input was evaluated. The preliminary results showed an overall increase in ergonomic awareness. The ordinance was distributed in about 120000 copies, and the labour inspectors found it to be a useful tool in their work. Citations concerning ergonomics had increased considerably during this period.     

The impact and feasibility of international/national standards in the prevention of musculoskeletal injuries in developing countries

This paper considers various facets of a preventive scheme for musculoskeletal injuries and examines the role of standards in the terminology, investigation, reporting, compilation and computation in such schemes.     

Understanding factors affecting perceived sociability of social software

Sociability is considered to be important to the success of social software. The goal of the current study is to identify factors that affect the users’ perception of the sociability of social software and to examine the impact of sociability on the users’ attitude and behavior intentions. In a pilot study, 35 web users were interviewed to gain understanding of how they use social software to supplement their social life and to explore the possible factors that influence the users’ utilization of social software. In the first study, a questionnaire was developed, and 163 valid responses were collected. From the factor analysis results, seven important factors for social software design emerged, which accounts for 63.3% of the total variance. In the second study, 246 participants were asked to evaluate one of ten popular social applications with respect to the seven factors, their perceived sociability, and their attitudes and intention regarding the use of the applications. Results show that sociability is influenced by social climate, benefits and purposes, people, interaction richness, self-presentation, and support for formal interaction. System competency is not a sociability factor, but it significantly influences the user’s experience. Sociability and system competency, when combined, can predict 43% of users’ attitude towards social software and 51% of their intentions to use social software.     

Understanding workplace violence: The value of a systems perspective

Workplace violence is a leading form of occupational injury and fatality, but has received little attention from the ergonomics research community. The paper reports findings from the 2012 New Zealand Workplace Violence Survey, and examines the workplace violence experience of 86 New Zealand organisations and the perceptions of occupational health and safety professionals from a systems perspective. Over 50% of respondents reported violence cases in their organisation, with perpetrators evenly split between co-workers and external sources such as patients. Highest reported levels of violence were observed for agriculture, forestry and construction sectors. Highest risk factor ratings were reported for interpersonal and organisational factors, notably interpersonal communication, time pressure and workloads, with lowest ratings for environmental factors. A range of violence prevention measures were reported, although most organisations relied on single control measures, suggesting unmanaged violence risks were common among the sample.     

An empirical study of the factors affecting social network service use

Social network services are emerging as a promising IT-based business, with some services already being provided commercially such as Facebook, Cyworld and Xiaonei. However, it is not yet clear which potential audience groups will be key social network service participants. Moreover, the process showing how an individual actually decides to start using a social network service may be somewhat different from current web-based community services. Hence, the aims of this paper are twofold. First, we empirically examine how individual characteristics affect actual user acceptance of social network services. To examine these individual characteristics, we apply a Technology Acceptance Model (TAM) to construct an amended model that focuses on three individual differences: social identity, altruism and telepresence, and one perceived construct: the perceived encouragement, imported from psychology-based research. Next, we examine if the users’ perception to see a target social network service as human relationship-oriented service or as a task-oriented service could be a moderator between perceived constructs and actual use. As a result, we discover that the perceived encouragement and perceived orientation are significant constructs that affect actual use of social network services.     

Cost effectiveness of ergonomic redesign of electronic motherboard

A case study to illustrate the cost effectiveness of ergonomic redesign of electronic motherboard was presented. The factory was running at a loss due to the high costs of rejects and poor quality and productivity. Subjective assessments and direct observations were made on the factory. Investigation revealed that due to motherboard design errors, the machine had difficulty in placing integrated circuits onto the pads, the operators had much difficulty in manual soldering certain components and much unproductive manual cleaning (MC) was required. Consequently, there were high rejects and occupational health and safety (OHS) problems, such as, boredom and work discomfort. Also, much labour and machine costs were spent on repairs. The motherboard was redesigned to correct the design errors, to allow more components to be machine soldered and to reduce MC. This eliminated rejects, reduced repairs, saved US dollars 581495/year and improved operators' OHS. The customer also saved US dollars 142105/year on loss of business.     

The application of augmented reality technologies for the improvement of occupational safety in an industrial environment

In many branches of industry, occupational safety experts identified two main causes of worker injuries related to the usage of modern electro-mechanical machines and systems: inadequate training and insufficient work experience, and monotonicity of the tasks often performed repeatedly. In this paper, we present a system based on augmented reality (AR) technologies that can be useful in reducing these factors of risk at work and decreasing the error rate and preventing injuries. The system that is implemented on mobile devices is intended to project augmented reality instructions directly at the work place. A worker is led by the AR-system step by step through various work and safety procedures that should be performed. Each procedure consists of steps specified by a series of instructions accessed through an interactive check list. To ensure the safeness, if a confirmation is missing because of a skipped, incompletely, or wrongly performed step of a procedure, the AR-system blocks further implementation of the procedure and returns the worker to the previous step until the correct actions are carried out. At the same time, interactive work with the checklist breaks the monotonicity of the job. The system is personalized according to skills of a worker by taking into account his professional training and work experience. Depending on that it is determined the amount of data to be displayed to a worker helping even less skilled workers to perform a task.As a case study, the proposed approach is implemented as an instructional and occupational safety system for work at a universal lathe, which is an element of many technological processes of Thermal Power Plant Ugljevik in the Republika Srpska, Bosnia and Herzegovina, where this AR-system was experimentally implemented and verified.     

Mining significant factors affecting the adoption of SaaS using the rough set approach

Despite that Software as a Service (SaaS) seems to be the most tempting solution among different types of cloud services, yet it has not been adopted to-date with as much alacrity as was originally expected. A variety of factors may influence the adoption of SaaS solutions. The objective of this study is thus to explore the significant factors affecting the adoption of SaaS for vendors and enterprise users. An analytical framework is proposed containing two approaches—Technology Acceptance Model (TAM) and Rough Set Theory (RST). An empirical study on the IT/MIS enterprises in Taiwan is carried out. The results have revealed a considerable amount of meaningful information, which not only facilitates the SaaS vendors to grasp users’ needs and concerns about SaaS adoption, but also helps the managers to introduce effective marketing strategies and actions to promote the growth of SaaS market. Based on the findings, some managerial implications are discussed.     

An investigation the factors affecting MIS student burnout in technical-vocational college

Management information system (MIS) students are one of the most important information system (IS) employee sources. However, the determinants of student's burnout for MIS major students have received little attentions, despite their importance as indicator in predicting professional burnout and their working intention after their graduation and becoming IS professionals. This study explores the antecedents of student burnout for MIS major at technical-vocational college. Self-efficacy, social support, and sex-role were considered as antecedents to MIS student burnout. A questionnaire method by self-administered technique was used in this study. Multiple regression analysis was used to analyze the hypotheses. Statistical results displayed that MIS students with social support, self-efficacy and femininity have predictive power over student burnout. MIS students with social support and masculinity also have predictive power over self-efficacy.     

彩色地毯图案边缘提取方法

针对新疆民族地毯的制作工艺及图案基元的构造,提出一种结合颜色聚类与边缘检测的图案边缘提取方法。根据需要确定待处理区域,使用中心为[-8]的拉普拉斯滤波器对其增强;采用K-means颜色聚类对增强后的目标区域进行聚类,根据颜色分割出目标基元的大致轮廓;运用Canny算子进行边缘检测提取出图案基元闭合边缘并采用Freeman链码的压缩形式进行表示。实验结果表明,该方法对新疆民族地毯多样化的图案基元的提取具有较好的效果且为民族元素数字化处理奠定了良好的基础。