• Geomechanics and Engineering
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• v.18 no.2
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• pp.215-224
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• 2019

Excavation of long tunnels by shielded TBMs is a safe, fast, and efficient method of tunneling that mitigates many risks related to ground conditions. However, long-distance tunneling in great depth through adverse geological conditions brings about limitations in the application of TBMs. Among various harsh geological conditions, squeezing ground as a consequence of tunnel wall and face convergence could lead to cluttered blocking, shield jamming and in some cases failure in the support system. These issues or a combination of them could seriously hinder the performance of TBMs. The technique of excavation has a strong influence on the tunnel response when it is excavated under squeezing conditions. The Golab water conveyance tunnel was excavated by a double-shield TBM. This tunnel passes mainly through metamorphic weak rocks with up to 650 m overburden. These metamorphic rocks (Shales, Slates, Phyllites and Schists) together with some fault zones are incapable of sustaining high tangential stresses. Prediction of the convergence, estimation of the creeping effects and presenting strategies to overcome the squeezing ground are regarded as challenging tasks for the tunneling engineer. In this paper, the squeezing potential of the rock mass is investigated in specific regions by dint of numerical and analytical methods. Subsequently, several operational solutions which were conducted to counteract the challenges are explained in detail.

• Korean Journal of Family Welfare
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• v.23 no.4
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• pp.575-593
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• 2018

Online and offline are not separate worlds, especially for adolescents. Many friends in offline settings originally met each other online, but cross-domain influences have rarely been examined. This study aims to examine how much time adolescents spend with peers in online and offline settings, and how time spent with peers influences their online and offline delinquent behaviors during their middle school years. This study used data from the Korean Children & Youth Panel Survey (KCYPS). We focused on students for whom information was available from all three years of middle school. We used a cross-lagged panel model to examine the bi-directional effect of online and offline behaviors over time. Results show that more time spent with peers offline was associated with more offline delinquency, and more time spent with peers online was associated with more online delinquency. Cross-domain influences were also found: more time with peers offline increased online delinquency, and vice versa. However, this adverse cross-domain influence was observed only for male adolescents, not for female adolescents. Implications for intervention programs are discussed for male and female adolescents.

• Korean Journal of Environmental Agriculture
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• v.40 no.3
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• pp.194-202
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• 2021

BACKGROUND: Towards achievement of sustainable agriculture, using microbial inoculants may present promising alternatives without adverse environmental effects; however, there are challenging issues that should be addressed in terms of effectiveness and ecology. Viability and stability of the bacterial inoculants would be one of the major issues in effectiveness of microbial pesticide uses, and the changes within the indigenous microbial communities by the inoculants would be an important factor influencing soil ecology. Here we investigated the stability of the introduced bacterial strains in the soils planted with barley and its effect on the diversity shifts of the rhizosphere soil bacteria. METHODS AND RESULTS: Two different types of bacterial strains of Bacillus thuringiensis and Shewanella oneidensis MR-1 were inoculated to the soils planted with barley. To monitor the stability of the inoculated bacterial strains, genes specific to the strains (XRE and mtrA) were quantified by qPCR. In addition, bacterial community analyses were performed using v3-v4 regions of 16S rRNA gene sequences from the barley rhizosphere soils, which were analyzed using Illumina MiSeq system and Mothur. Alpha- and beta-diversity analyses indicated that the inoculated rhizosphere soils were grouped apart from the uninoculated soil, and plant growth also may have affected the soil bacterial diversity. CONCLUSION: Regardless of the survival of the introduced non-native microbes, non-indigenous bacteria may influence the soil microbial community and diversity.

• East Asian Journal of Business Economics (EAJBE)
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• v.10 no.4
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• pp.55-64
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• 2022

Purpose - Corporate reading management requires employees capable of doing their job since employee performance is crucial to the firm's profitability. The objective of this study was to evaluate the positive effects of corporate reading management on employee management. It focuses on factors increasing employee productivity and the impacts corporate management brings about on the overall productivity of any kind of company. Research design, Data, and methodology - The current authors have investigated and conducted the qualitative content analysis (QCA) to obtain the adequate textual dataset in the prior and current literature. One of the primary benefits of doing research using content analysis is that it enables the researcher to employ a combination of qualitative and quantitative research methodologies. Result - Based on the review of the prior literature, the present authors found that there are four corporate reading management solutions to improve employee performance, following those instructions - A. Increased Motivation and Productivity, B. Employee Development, C. Businesses' Objective Alignment, and D. Improved Work Environment. Conclusion - This study addressed and figured out different factors that reading corporate can apply to influence employee performance, thus increasing the company's productivity. Future research should evaluate the adverse effects businesses might face from unfavorable working environments. The research also needed to address how ethics influences employee performance.

• East Asian Economic Review
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• v.26 no.3
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• pp.205-225
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• 2022

Different types of corporate ownership may affect the environment among firms and could influence the decisions of new entities in the region. This study determines the role of state-owned enterprises (SOEs) in hindering new foreign manufacturing firms in the Yangtze River delta (YRD). The negative binomial regression is used for city-sector level data and the following points summarize the results: Firstly, the unique privileges that SOEs enjoy alongside governmental support create difficulties for foreign firms trying to establish themselves near existing SOEs. Secondly, although core cities are more attractive to foreign firms than peripheral cities, the role of core-periphery reveals that, in spite of all the regional advantages core cities could offer, whenever the share of SOEs is higher, the core-periphery system will have an adverse impact on new foreign firms. In other words, government preference for SOEs can suppress the attraction of foreign start-ups. However, after 2008, the governmental authorities finally succeeded in implementing their promising policy of fair treatment and competition in only the core cities.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.6
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• pp.447-453
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• 2021

Human resources play a key role in developing and enhancing the manner in which an organization change. In fact, the role of human resource-related quality management has contributed greatly to the growth of the organization in both the short and long term. The purpose of the current study is to identify factors that influence human resource retention in Hanoi in the backdrop of growing economic performance of Hanoi in Vietnam's economy. Primary data was collected through questionnaires of 280 respondents from the four districts in Hanoi, including 25.2% of respondents working in Cau Giay district, 21.2% in Dong Da district, 34.2% in Ha Dong district, and 19.4% in Thanh Xuan district. After applying Cronbach's Alpha and Explore Factor Analysis (EFA) analysis, Durbin-Watson test, empirical results demonstrate that relationship among co-workers has a significant and positive contribution on the maintenance of human resources in the organization. Additionally, higher welfare facilities for an employee are more likely to impact the maintenance of human resources in the organization. Factors such as working environment, job placement, and leadership relationship have no adverse effect on the maintenance of human resources, although a positive impact could be established in all cases.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.2
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• pp.67-77
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• 2021

Factors that cause fatigue, such as circadian rhythm abnormalities, have adverse effects on long-haul flights. Among many elements, the present study focused on the flight crew's expertise as a crucial factor that could influence their fatigue. The purpose of the study was to demonstrate whether long-haul flights cause fatigue and to examine whether this symptom differed between low- and high-experienced flight crews. A total of 62 Korean flight crews were informed to perform a five-minute psychomotor vigilance task twice each before and after the flight to measure objective fatigue level. Also, they were asked to indicate current flight experience to identify their expertise. Results revealed that fatigue was significantly increased after the flight compared to before the flight but this increase was significant for flight crews with low expertise not for flight crews with high expertise. Implications of our findings and limitations of the present study were discussed.

• Structural Engineering and Mechanics
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• v.86 no.1
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• pp.17-27
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• 2023

To investigate the mechanical behavior of the post-tensioned prestressed concrete lining (PPCL), the desilting tunnel of the Xiaolangdi Hydro Project in China is adopted as a case, and a detailed three-dimensional continuum model verified by the observation results is established for the PPCL. The radial stresses, longitudinal stresses, axial forces and bending moments of the PPCL under the completed cable tension condition (CCTC) and design water pressure condition (DWPC) are analyzed, respectively. The numerical results reveal that the PPCL concrete is significantly compressed in the circumferential direction by the prestress, while the prestress has a negligible influence on the radial stresses of the PPCL concrete. It should be noted that the concrete near the anchor slots has a complex and adverse stress state with stress concentration, longitudinal tensioning and large bending moment. In addition, a simplified shell model and a further simplified beam model which can take the influences of the prestress loss and the anchor slot into consideration are proposed for the PPCL. The results of the simplified models are in a good agreement with these of the three-dimensional continuum model, and they can be used as efficient approaches for the structural design and analysis of the PPCL.

• Steel and Composite Structures
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• v.42 no.1
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• pp.75-90
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• 2022

The pointwise equilibrium polynomial (PEP) element considering local second-order effect has been widely used in direct analysis of many practical engineering structures. However, it was derived according to Euler-Bernoulli beam theory and therefore it cannot consider shear deformation, which may lead to inaccurate prediction for deep beams. In this paper, a novel beam-column element based on Timoshenko beam theory is proposed to overcome the drawback of PEP element. A fifth-order polynomial is adopted for the lateral deflection of the proposed element, while a quadric shear strain field based on equilibrium equation is assumed for transverse shear deformation. Further, an additional quadric function is adopted in this new element to account for member initial geometrical imperfection. In conjunction with a reliable and effective three-dimensional (3D) co-rotational technique, the proposed element can consider both member initial imperfection and transverse shear deformation for second-order direct analysis of frame structures. Some benchmark problems are provided to demonstrate the accuracy and high performance of the proposed element. The significant adverse influence on structural behaviors due to shear deformation and initial imperfection is also discussed.

• Steel and Composite Structures
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• v.45 no.3
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• pp.369-388
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• 2022

Composite effect between steel and recycled aggregate concrete (RAC) in steel reinforced-RAC (SRRAC) structures can effectively improve RAC's adverse mechanical properties due to the natural defects of recycled coarse aggregate (RCA). However, the performance of SRRAC after thermal exposure will have a great impact on the safety of the structure. In this paper, firstly, the mechanical properties of SRRAC structures after high temperatures exposure were tested, including 24 SRRAC columns and 32 SRRAC beams. Then, the change rules of beams and columns performance with the maximum temperature and replacement percentage were compared. Finally, the formulas to evaluate the residual bearing capacity of SRRAC beams and columns after exposure to high temperatures were established. The experimental results show that the maximum exposure temperature can be judged by the apparent phenomenon and mass loss ratio of RAC. After high temperatures exposure, the mechanical properties of SRRAC beams and columns change significantly, where the degradation of bearing capacity and stiffness is the most obvious. Moreover, it is found that the degradation degree of compression member is more serious than that of flexural member. The formulas of residual bearing capacity established by introducing influence coefficient of material strength agree well with the experimental results.