Member Sizes Research Articles

Optimization of the structural coupling between RC frames, CLT shear walls and asymmetric friction connections

This paper focuses on the optimum design of the e-CLT technology. The e-CLT technology consists in adding cross laminated timber (CLT) walls to an existing reinforced concrete (RC) infilled frame via asymmetric friction connection (AFC). The authors carried out quasi-static and nonlinear dynamic analyses. The RC frame is modeled in OpenSees by fiber-section-based elements with force-based formulation. The contribution of the infill is simulated using a degrading data-driven Bouc–Wen model with a slip-lock element while the AFC is modelled with a modified Coulomb model. Different types of infill, aspect ratio, scaling, and member size are considered. The benefits of using e-CLT technology are discussed and the ranges of optimum performance of the AFC are estimated. A comparison of the performance of traditional infills with the e-CLT system is presented. The authors provide optimum intervals of the ratio between slip force and in-plane stiffness of the CLT panel, following energy and displacement-based criteria. The seismic displacement demand under various seismic scenario is investigated. Correlations between the RC characteristics and the optimum design ratios bestow possible criteria for the design of the AFC.

Structural engineering from an inverse problems perspective.

The field of structural engineering is vast, spanning areas from the design of new infrastructure to the assessment of existing infrastructure. From the onset, traditional entry-level university courses teach students to analyse structural responses given data including external forces, geometry, member sizes, restraint, etc.—characterizing a forward problem (structural causalities structural response). Shortly thereafter, junior engineers are introduced to structural design where they aim to, for example, select an appropriate structural form for members based on design criteria, which is the inverse of what they previously learned. Similar inverse realizations also hold true in structural health monitoring and a number of structural engineering sub-fields (response structural causalities). In this light, we aim to demonstrate that many structural engineering sub-fields may be fundamentally or partially viewed as inverse problems and thus benefit via the rich and established methodologies from the inverse problems community. To this end, we conclude that the future of inverse problems in structural engineering is inexorably linked to engineering education and machine learning developments.

SGMRP: Scalable Geographic Multicast Routing Protocol for Mobile Ad Hoc Networks

Recently, group communications over Mobile Ad hoc Networks (MANETs) have received considerable attention. Group communication needs support of multicast routing protocols for simultaneous delivery information of group of receivers. Thus, designing effective and efficient multicast routing protocol is necessary to support this kind of applications. Several efforts have been adopted to improve multicast routing. However, most of them did not consider the scalability issue. In this paper, we propose a novel Scalable Geographic Multicast Routing Protocol (SGMRP) to improve the scalability of multicast routing with reduced overhead. SGMRP uses virtual clustering strategy to implement scalable routing and efficient group management. This scheme based on partitioning the network into sectorial zones. The proposed solution performs efficient packet forwarding with reduced communication overhead. This scheme reduces the number of participating nodes and eliminates the duplicate packets. Compared with on Demand Multicast Routing Protocol (ODMRP) and Efficient Geographic Multicast Protocol (EGMP), simulation results show that SGMRP delivers more packets with significantly reduced overhead regardless of the network size, mobility speed and number of multicast members.

Study on the steady state of the propagation model of consumers’ perceived service quality in the community group-buying

The consumption stickiness relationship established by community group buying is a typical complex social network. The network structure, member size, interaction frequency and purchase quantity are determined by the effective communication of customer perceived service quality (PSQ). This paper introduces the social reinforcement effect to construct a G-SCIR model of PSQ propagation in the community group-buying, and improves the calculation method of propagation probability and node status attributes. We use numerical simulation methods to explore how the social reinforcement effect can promote the spread of PSQ and achieve a steady state by influencing recovered nodes. The simulation results show that the G-SCIR model proposed in the paper has better stability and higher coverage than the traditional SCIR model. The change trend of the attributes of each node in the network is also closer to the real one, which can effectively simulate the propagation process and evolution characteristics of PSQ in the context of community group-buying. Meanwhile, the paper verifies that the steady state of PSQ propagation is usually affected by its initial conversion probability of community group-buying, its upper limit and social reinforcement factor, and there are significant Markov properties in the propagation process of PSQ. The findings may further enrich the community business and online group buying theory, and provide theoretical reference and practical guidance for community group-buying enterprises to optimize market layout and formulate scientific communication strategies.

Assessment on the Progressive Collapse Resistance of a Long-Span Curved Spatial Grid Structure with Main Trusses

The progressive collapse resistance of the terminal building of Zhongchuan Airport in Lanzhou, China was studied, which is a long-span curved spatial grid structure with main trusses. Firstly, the finite element model was built using MSC. Marc software adopting the fiber model based on material. Secondly, an improved method of zoned concept judgment and sensitivity analysis was proposed to determine the key components. Thirdly, the initial failure components were removed individually based on the alternate load path method (AP method). The responses of remaining structure were calculated using nonlinear dynamic analysis method. Lastly, the influences brought by the cross-sectional sizes of grid members were investigated through conducting parametric analysis. According to the results, the proposed selection method can avoid omitting the key components. The structural responses are significant when removing the concrete filled steel tubular (CFST) column SC14 directly supporting the front middle part of the roof, with a maximum vertical displacement of 10 m at cantilever end, which should be focused on for this kind of large-span spatial structure. In addition, the tensile strength and cross-sectional area of the upper and lower chords should be increased by 20% to enhance the progressive collapse resistance of the structure, and the changes of axial compression ratios of the columns supporting the roof have little effects.

Determinants of Jobs Satisfaction of Female Teachers: An Evidence from District Hafizabad, Pakistan

Job satisfaction seems to have an important positive relationship with job performance. The current study was conducted to estimate the impact of different factors on the job satisfaction of female teachers. Data were collected by using a pre-tested questionnaire from a sample of 400 female school teachers working in District Hafizabad, Punjab, Pakistan. Primary data were collected about socioeconomic characteristics of teachers and other relevant factors for job satisfaction. The impact of different factors on job satisfaction of female teachers was estimated by using the Binary Logistic Model. Results of the study showed that the impact of independent variables of age, education, distance, family structure, family members, and the number of children is highly significant. At the same time, the impact of other variables, including experience, region, marital status, salary and job status is not significant. There is a positive and highly significant impact of education on female teacher’s job satisfaction. There is a negative and highly significant effect of the variable of school distance on female teachers’ job satisfaction. There is a negative and highly significant effect of the variable of joint family structure on job satisfaction. If the respondent has a joint family structure, it will negatively affect job satisfaction. There is a positive and highly significant impact of the variable of family members on job satisfaction. If the size of a family member increases by one unit, it will positively affect job satisfaction. There is a negative and highly significant impact of the variable of the number of children on female job satisfaction. If the number of children increases by one unit, there would be 0.788 fewer chances to be satisfied with her job.

Data-driven professional factors for ACI 318 one-way shear strength

Uncertainty is inherent in analytical models because of simplifications and approximations, and this uncertainty is referred to as the professional factor in reliability analyses context. In the past, a lack of agreement regarding the accuracy of the ACI 318 building code requirements for structural concrete one-way shear equations made meaningful calibration of a shear resistance factor for design unjustifiable. Only expert opinion estimation of professional factors was available. Recently, in the latest edition of the ACI 318, the one-way shear design equations for reinforced concrete members significantly changed. This paper describes an effort to determine data-driven professional factors that characterize the previous and new ACI 318 analytical models for one-way shear strength. The resulting professional factors were determined through analysis of the extensive joint DAfStb-ACI Committee 445-D Shear database. The proposed, data-driven professional factors are markedly different than the subjective, expert-opinion professional factors proposed in the past. Furthermore, the analyses indicate that the new ACI 318-19 one-way shear equations represent an improvement across the full range of member sizes—especially for members without shear reinforcement. Therefore, a reliability-based calibration of the ACI 318 one-way shear resistance factor using the proposed professional factors is warranted.

Do the Attributes of Audit Committee Explain Non-Performing Loans? Evidence from an Emerging Economy

This study examined whether various attributes of the audit committee of listed banks in Bangladesh explain the level of non-performing loans (NPLs). This study used a panel data set comprising all 30 listed banks with 250 bank-year observations for the period 2013–2017. It employed the random-effects GLS regression model with cluster robust standard error and AR (1) disturbance to examine the effect of several audit committee attributes on NPLs. We found that holding audit committee meetings frequently and a higher number of independent members in the audit committee facilitate to reduce NPLs. We, however, find no explicit evidence that the other attributes of the audit committee examined (audit committee size, financial experience and financial literacy of the audit committee members, professional qualifications of the audit committee Chairman) contribute in reducing NPLs. The findings will be useful for policymakers of the banking sector in Bangladesh and the relevant regulatory bodies in enabling them to understand the role of the various attributes of the audit committee in the incidence of NPLs. Keywords: attributes, audit committee, non-performing loans (NPLs), listed banks, Bangladesh

The Advantage of Incumbents in Coalitional Bargaining

Political parties frequently form coalitions with each other to pursue office or policy payoffs. Contrary to a prominent argument, the distribution of rents within the coalition does not always reflect the relative sizes of the coalition members. We propose that this is at least partially due to an incumbency advantage in coalitional bargaining. To evaluate this argument empirically, we construct a data set of candidates, parties, and members of the executive in Finnish local governments. We first use a regression discontinuity design to document a personal incumbency advantage in nominations to executive municipal boards. We then show that an incumbency premium is present also at the party level. Using an instrumental variable strategy that hinges on within‐party close elections between incumbents and non‐incumbents, we find that, ceteris paribus, having more re‐elected incumbents increases party’s seat share in the executive.

Pengaruh Karakteristik Dewan Pengawas Syariah (DPS) Terhadap Kinerja Keuangan Bank Umum Syariah Yang Terdaftar pada Otoritas Jasa Keuangan (OJK) Indonesia

This paper investigated the effect of the characteristics of the Sharia Supervisory Board (SSB) on the financial performance of Islamic banks listed in Financial Service Authority of Indonesia (OJK) during the period 2016-2020. SSB characteristics consist of size, number of meeting, educational qualification, and reputation. Using purposive sampling, we obtained samples from 13 Islamic Banks in Indonesia. Data was collected from annual report of selected banks for the year 2016-2020 and has been analyzed using the multiple linear regression. The results show that educational qualification of SSB members have significant positive effect on the financial performance. While size, the meeting and reputation of SSB members had no significant effects on the financial performance. This paper gives a comprehensive literature survey on the effect of the characteristics of the Sharia Supervisory Board (SSB) on the financial performance and robustness checks provides support for the findings.

Length scale control schemes for bi‐directional evolutionary structural optimization method

AbstractThis work develops length scale control schemes for bi‐directional evolutionary structural optimization method, enabling an enhanced and flexible control of the method on structural member sizes. Specifically, the maximum length scale control is achieved by constraining local material volumes below a threshold value, which is determined upon the allowed maximum length. The massive per‐element volume constraints are aggregated by the p‐norm global measure. The aggregated volume constraint is augmented to the conventional compliance design objective through a Lagrange multiplier. On the other hand, the minimum length scale control is achieved by a post‐processing modification of local feature according to the skeleton detected from a preliminarily optimized topology. The sensitivity numbers of the local structural features that violate the minimum length scale constraint are compensated during the post‐processing modification. Both 2D and 3D benchmark design results show that the proposed schemes are effective and efficient in controlling both the maximum and minimum structural length scales.

The Impact of Corporate Governance on Earnings Management: The Case Of Pakistan Textile Industry

Due to globalization and expansion in the world markets, the sensitivity of investor’s confidence has become a challenge especially in the wake of issues related to stock prices, earnings management (EM), the stability of income levels and corporate governance (CG) application. This study aims to explore the usefulness of four traits of corporate governance mechanism in constraining earnings management activities. By using five years’ observations of 109 textile companies listed on Pakistan Stock Exchange (PSX) for the period 2013-2017. Traits comprising of board size, gender diversity, board experience and qualification of board member are analyzed using Ordinary Least Square (OLS). Results of the study submit that board experience; finance qualification and business qualification have a negative significant impact on EM thus contends that experienced board members having business and finance qualification discourage earnings manipulation. While, positive and significant impact of board size on earnings management is an indication of loss of control due to its large size. Moreover, gender diversity and chartered accountancy are found irrelevant to EM in our case.

Analysis of Household Food Security of Fishermen in Coastal Area, Bangil District, Pasuruan Regency

The low income of fishermen makes it difficult to fulfill basic household food needs and non-food basic needs. The purpose of this study was to analyze the level of energy adequacy and the level of protein adequacy and identify the factors that affect the food security of fishermen's households. The first analysis was carried out descriptively by combining food expenditure and energy consumption indicators. The second analysis uses a logit model regression analysis. The analysis results show that the food security condition of fishermen's households is at the food shortage level of 43.34%. Fisherman households in the food insecurity criteria are 10%, and food security is 23.33%. It means that more than 60% of fishermen's household income is spent on food consumption. The low income received has resulted in fisherman households being unable to allocate food expenditures to meet the nutritional adequacy of their household. The factors that influence the food security of fishermen's households are the size of the household members, household expenditures, and the nutritional knowledge of housewives. Local governments should coordinate with other institutions to formulate policies and plans for economic development in coastal areas.

Detection and Response to an HIV Cluster: People Living Homeless and Using Drugs in Seattle, Washington

The HIV epidemic in King County, Washington has traditionally been highly concentrated among men who have sex with men, and incidence has gradually declined over 2 decades. In 2018, King County experienced a geographically concentrated outbreak of HIV among heterosexual people who inject drugs. Data sources to describe the 2018 outbreak and King County's response were partner services interview data, HIV case reports, syringe service program client surveys, hospital data, and data from a rapid needs assessment of homeless individuals and people who inject drugs. In 2020, the authors examined the impact of delays in molecular sequence analyses and cluster member size thresholds, for identifying genetically similar clusters, on the timing of outbreak identification. In 2018, the health department identified a North Seattle cluster, growing to 30 people with related HIV infections diagnosed in 2008-2019. In total, 70% of cluster members were female, 77% were people who inject drugs, 87% were homeless, and 27% reported exchanging sex. Intervention activities included a rapid needs assessment, 2,485 HIV screening tests in a jail and other outreach settings, provision of 87,488 clean syringes in the outbreak area, and public communications. A lower cluster size threshold and more rapid receipt and analyses of data would have identified this outbreak 4-16 months earlier. This outbreak shows the vulnerability of people who inject drugs to HIV infection, even in areas with robust syringe service programs and declining HIV epidemics. Although molecular HIV surveillance did not identify this outbreak, it may have done so with a lower threshold for defining clusters and more rapid receipt and analyses of HIV genetic sequences.

Structural properties of superior design solutions of steel buildings associated with BRBs

A design algorithm is proposed for rational seismic design solutions of steel buildings associated with buckling restrained braces (BRB). The strengths and locations of BRBs in addition to the section sizes of structural members are considered as discrete design variables. The steel volume including BRBs is minimized as an objective function under various practical design constraints. A seven-story office building is examined for application in two different types of structural systems, i.e. one mainly consisting of lateral frames and the other with limited utilization of lateral frames typically in perimeter separately from gravity frames. The derived solutions, defined as superior design solutions (SDSs), satisfy serviceability and limit-state constraints, taking into consideration the seismic energy dissipation effect of BRBs using the calculation of resistance and limit-state method. Their rationale is validated with response history analysis. Furthermore, the influences in SDSs by the seismic demand levels and elastic member constraint are investigated. The structural characteristics of SDSs associated with BRBs are objectively evaluated using the proposed design algorithm.

Workplace spirituality and organizational justice in turnover intention of mental health professionals at small-sized centres.

To investigate the influence of workplace spirituality and organizational justice on the turnover intentions of mental health professionals working in small-sized communities. Many community mental health facilities in Korea are consist of the small size of members, and the turnover rate of mental health professionals is high. However, the influence of individual and organizational factors for lowering the turnover is not clearly identified. This was a descriptive study. Data of 168 participants were collected through a self-reported online questionnaire using a convenience sample, June 2020. Multiple regression analysis uses interactional justice (β= -.437, p= .002), distributional justice (β= -.190, p= .011) and age (β= -.152, p= .033) that were the most important predictors of turnover intention. Orgnisational factors such as distributional and interactional justice affect to reduce turnover intention more than an individual factor like the workplace spirituality of professionals. Small-sized mental health institutions in the community should establish a clear working guideline that can make the distribution, procedure and interactional justice. Because only a small percentage of nurses work at community mental health facilities, it is necessary to reduce turnover by creating a work environment where young nurse practitioners can work long-term and grow into leaders.

Improving the seismic performance of reinforced concrete frames using an innovative metallic-shear damper

In reinforced concrete (RC) frames, the applied seismic energy is dissipated through the ductile behavior of RC moment resisting frames. The main elements of the RC frames carry the gravity loads in addition to the seismic loads. Since the RC frames are sensitive to gravity loads, the ductility of the frames is reduced by increasing the gravity loads. Moreover, because of the low stiffness of the RC moment frames, huge member sizes of structural elements are required to control lateral drifts under lateral loading. In addition, the existing RC moment frame buildings with non-ductile characteristics pose a considerable hazard during earthquakes. To solve the mentioned problems, an innovative metallic damper with a shear link (metallic-passive energy damper) was developed in this paper. The proposed damper not only enjoys an easy fabrication and a good seismic performance but also can be easily replaced after a severe earthquake. Since the damper does not carry the gravity loads, replacing the damper does not affect the severability of the building during repairing. The main goal of this study is to confine the plastic deformation in the proposed damper. The numerical results indicated that the proposed damper improved the behavior of the RC frame in elastic and inelastic zones. It enhanced the shear capacity, shear stiffness, energy absorption, and ductility of the RC moment resisting frame. The results indicated that the proposed damper enhances the shear stiffness and the ultimate shear capacity from a minimum of 11% to a maximum of 24% and from a minimum of 11% to a maximum of 48%, respectively. Also, the proposed damper improved the yielding strength from a minimum of 53% to a maximum of 61%. Moreover, the dynamic analysis indicated that the damper improved the behavior of the system in the case of maximum lateral displacement and base shear. Based on the time-history dynamic analysis, dampers in the 5- and 10-story frames are more effective compared to the 15-story frame. This result confirms the suitable performance of the proposed damper. Herein the required equations and the recommendations for the design of the proposed metallic-shear damper have been presented.

Incremental Dynamic Analysis of Concentric X‐Braced Frames Designed to the TBEC 2018

AbstractConcentrically braced frames (CBF) are an efficient lateral force resisting system which provides significant lateral stiffness and lateral strength. One of the commonly used configurations of CBFs are cross braced (X‐braced) frames where braces are placed diagonally between the beam‐column joints of adjacent stories. The current Turkish seismic code, Turkish Building Earthquake Code 2018 (TBEC), was published in 2018 and superseded the former code, Turkish Earthquake Code 2007 (TEC) as of January 2019 with several differences such as introduction of yield mechanisms for CBFs, seismic hazard levels, and calculation of earthquake loads. Due to these differences, CBFs designed to TBEC are expected to yield different member sizes compared to TEC. Although the seismic behaviour of CBFs designed to TEC is well‐understood, that of CBFs designed to TBEC is still unknown and there has been no study on this topic. This study aims to assess the seismic performance of X‐braced frames designed to TBEC. To this end, a two‐story X‐braced frame was considered, and the seismic collapse performance of this frame was evaluated by adopting incremental dynamic analysis (IDA) under a set of twelve ground motions. The results of this preliminary study have provided insight into the collapse performance of CBFs designed to TBEC.

Editorial: Composite Use of High Strength Steel and Concrete Materials for Sustainable Civil Engineering

The need for sustainable construction has been hastened world-widely aiming to reduce the use of construction materials and labor costs. To do so, high strength materials will be one option.The higher the strength, the smaller the member size is required. This will free up more usable floor area and require fewer materials and construction work. The composite use of them makes the aim easier to be achieved. To bridge the gap between theoretical development and practical application, a special issue with the research topic of "Composite Use of High Strength Steel and Concrete Materials for Sustainable Civil Engineering" has been organized by the Guest Surely the high temperature and cooling deteriorated the bond strength, and this would have an adverse influence on the ultimate load-carrying capacity of the composite members.The diverse nature of contributions in this collection is a testament to the cross-disciplinary research activities about the composite use of high strength materials. Nevertheless, there is a common thread running through all contributions where high strength, when properly achieved, can be the source of great creativity in achieving more sustainable construction.

Integrating Geometric Data into Topology Optimization via Neural Style Transfer.

This research proposes a novel topology optimization method using neural style transfer to simultaneously optimize both structural performance for a given loading condition and geometric similarity for a reference design. For the neural style transfer, the convolutional layers of a pre-trained neural network extract and quantify characteristic features from the reference and input designs for optimization. The optimization analysis is evaluated as a single weighted objective function with the ability for the user to control the influence of the neural style transfer with the structural performance. As seen in architecture and consumer-facing products, the visual appeal of a design contributes to its overall value along with mechanical performance metrics. Using this method, a designer allows the tool to find the ideal compromise of these metrics. Three case studies are included to demonstrate the capabilities of this method with various loading conditions and reference designs. The structural performances of the novel designs are within 10% of the baseline without geometric reference, and the designs incorporate features in the given reference such as member size or meshed features. The performance of the proposed optimizer is compared against other optimizers without the geometric similarity constraint.