• Journal of Construction Engineering and Project Management
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• v.10 no.1
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• pp.16-32
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• 2020

Cost and time control of projects is important in preventing project failure. However, achieving effective cost and time control in practice is often challenging. The challenges of project cost and time control in practice are investigated by carrying out a questionnaire survey on the top 150 construction contractors in the UK followed by in-depth semi-structured interviews of practitioners from 15 construction companies in the country. Quantitative analysis reveals that design change is the most important factor inhibiting the ability of UK contractors from effectively controlling both the cost and time of construction projects. Four of the top five factors inhibiting effective cost control are also the top factors inhibiting effective time control albeit in a different order. These top factors-design changes, inaccurate evaluation of project time/duration, risk and uncertainty, non-performance of subcontractors and nominated suppliers were also found to be endogenous factors to the project. Additionally, qualitative analysis of the interviews reveals 16 key challenges to prevent for effective project cost and time control in practice. These are classified into four categorised based on where they stem from as follows; from the organisation (1. Lack of integration of cost and time during project control, 2. lack of management buy-in, 3. complicated project control systems and processes, 4. lack of a project control training regime); from the construction management/project management approach (5. Lapses in integration of interfaces, 6. project control not being implemented from the early stages of a project, 7. inefficient utilisation and control of labour, 8. limited time devoted to planning how a project will be controlled at the outset); from the client; (9. Excessive authorisation gates, 10. use of adversarial and non-collaborative forms of contracts, 11. communication problems within client set-up, 12. obstructive client representatives) and; from the project team (13. Lack of detailed/complete design, 14. lack of trust among the project partners, 15. limited time devoted to project control on site, 16. non-factual reporting). The study posits that knowledge of these project control inhibiting factors and challenges is the first step at ensuring they are avoided and enable the implementation of a more effective project cost and time control process in practice.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.5
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• pp.10-17
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• 2013

This paper describes a study on after-burning suppressant in a solid propellant to reduce the plume formed outside of rocket nozzles, which could expose the launch site and the flight track. The minimum smoke propellant to enhance the stealth ability was formulated in terms of the kinds and the effects of after-burning suppressant on the ballistic performance and the amount of primary smoke. A after-burning suppressant, $K_2SO_4$ of about 1.1% weight content was found to show profound reduction of the rocket plume, giving negligibly slight increase in pressure exponent of burning rate. Also minimum smoke propellant with less than 1.1% of $K_2SO_4$ corresponds to A-class satisfaction in primary smoke by AGARD standard.

• Smart Structures and Systems
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• v.8 no.2
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• pp.173-190
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• 2011

As a practical and effective seismic resisting technology, the base isolation system has seen extensive applications in buildings and bridges. However, a few problems associated with conventional lead-rubber bearings have been identified after historical strong earthquakes, e.g., excessive permanent deformations of bearings and potential unseating of bridge decks. Recently the applications of shape memory alloys (SMA) have received growing interest in the area of seismic response mitigation. As a result, a variety of SMA-based base isolators have been developed. These novel isolators often lead to minimal permanent deformations due to the self-centering feature of SMA materials. However, a rational design approach is still missing because of the fact that conventional design method cannot be directly applied to these novel devices. In light of this limitation, a displacement-based design approach for highway bridges with SMA isolators is proposed in this paper. Nonlinear response spectra, derived from typical hysteretic models for SMA, are employed in the design procedure. SMA isolators and bridge piers are designed according to the prescribed performance objectives. A prototype reinforced concrete (RC) highway bridge is designed using the proposed design approach. Nonlinear dynamic analyses for different seismic intensity levels are carried out using a computer program called "OpenSees". The efficacy of the displacement-based design approach is validated by numerical simulations. Results indicate that a properly designed RC highway bridge with novel SMA isolators may achieve minor damage and minimal residual deformations under frequent and rare earthquakes. Nonlinear static analysis is also carried out to investigate the failure mechanism and the self-centering ability of the designed highway bridge.

• Smart Structures and Systems
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• v.25 no.1
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• pp.111-122
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• 2020

Researchers up to date have introduced several Structural Health Monitoring (SHM) techniques with varying advantages and drawbacks for each. Satellite positioning systems (GPS, GLONASS and GALILEO) based techniques proved to be promising, especially for high natural period structures. Particularly, the GPS has proved sufficient performance and reasonable accuracy in tracking real time dynamic displacements of flexible structures independent of atmospheric conditions, temperature variations and visibility of the monitored object. Tall structures are particularly sensitive to oscillations produced by different sources of dynamic actions; such as typhoons. Wind forces induce in the structure both longitudinal and perpendicular displacements with respect to the wind direction, resulting in torsional effects, which are usually more complex to be detected. To efficiently track the horizontal rotations of the in-plane sections of such flexible structures, two main issues have to be considered: a suitable sensor topology (i.e., location, installation, and combination of sensors), and the methodology used to process the data recorded by sensors. This paper reports the contributions of the measurements recorded from dual frequency GPS receivers and uni-axial accelerometers in a full-scale experimental campaign. The Canton tower in Guangzhou-China is the case study of this research, which is instrumented with a long-term structural health monitoring system deploying both accelerometers and GPS receivers. The elaboration of combining the obtained rather long records provided by these two types of sensors in detecting the torsional behavior of the tower under ambient vibration condition and during strong wind events is discussed in this paper. Results confirmed the reliability of GPS receivers in obtaining the dynamic characteristics of the system, and its ability to capture the torsional response of the tower when used alone or when they are combined with accelerometers integrated data.

• Wind and Structures
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• v.30 no.4
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• pp.393-403
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• 2020

One of the growing concerns of the wind energy production is wind ramp events. To improve the wind ramp event forecasts, the nonlinear Kalman filter bias correction method was applied to 24-h wind speed forecasts issued from the WRF model at 70-m height in Zhangbei wind farm, Hebei Province, China for a two-year period. The Kalman filter shows the remarkable ability of improving forecast skill for real-time wind speed forecasts by decreasing RMSE by 32% from 3.26 m s_-1 to 2.21 m s_-1, reducing BIAS almost to zero, and improving correlation from 0.58 to 0.82. The bias correction improves the forecast skill especially in wind speed intervals sensitive to wind power prediction. The fact shows that the Kalman filter is especially suitable for wind power prediction. Moreover, the bias correction method performs well under abrupt weather transition. As to the overall performance for improving the forecast skill of ramp events, the Kalman filter shows noticeable improvements based on POD and TSS. The bias correction increases the POD score of up-ramps from 0.27 to 0.39 and from 0.26 to 0.38 for down-ramps. After bias correction, the TSS score is significantly promoted from 0.12 to 0.26 for up-ramps and from 0.13 to 0.25 for down-ramps.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.4
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• pp.1147-1159
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• 2015

The purpose of this study was to verify the analysis of level of importance and satisfaction in recognitions of elementary school students on useful classes among school sport clubs using Importance-Performance analysis. In order to achieve this objective, samples were taken by using convenience sampling method among non-probability sampling methods, and 384 data were used as the final valid samples for this study except 16 data with missing items or insincere responses. The results of frequency analysis, exploratory factor analysis, independent samples t-test, IPA analysis by using SPSS 20.0 were as follows. First, Iquadrant included education contents of enhance ability to ingenuity, teaching method of provides option, teaching method of encourage participation activity, education contents of the aspect of fun, evaluation of motor function and emotion, education contents of explains key contents easily, and education contents of understanding overall context. II quadrant included education environment of good sport facility, class environment of fair opportunity for activity, class atmosphere of arouses interest, and class atmosphere of autonomous and voluntary. III quadrant included diverse teaching method and instructor's demonstration, class atmosphere of systematic learning, evaluation of fairness, objectivity, and credibility, and an atmosphere that can exercise. IV quadrant included education contents of enable acquisition of knowledge and degree of improvement into consideration, and class atmosphere of trust and respect between instructor and student.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.12
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• pp.820-824
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• 2008

Electret filter media are used in general ventilation filters, disposable respirators, vehicle cabin filters, vacuum cleaners and room air cleaners. There are basic mechanisms of interception, inertial impaction, diffusion, gravitational settling, electrostatic attraction by which an aerosol particle can be deposited onto a fiber in a filter. The ability of fine particle removal strongly depends on the electrostatic forces between particles and polarized fibers. Thus, the stability of the fiber polarization is a major factor in the reliability of electret filters. In this study, the electret filter is made by electrospinning process using Polystyrene which is dissolved by 5 : 5 of Tetrahydrofuran (THF) and Dimethylformamide (DMF). Also the electrical properties and the filtration performances of electrospun filter media are Quantitatively investigated. Electrical properties of electrospun filters have been studied on surface charge potential and surface charge density. Also the filtration performance of the electret filters are evaluated on collection efficiency. The surface charge potential and the surface charge density of electrospun PS filters are increased with increasing applied voltage and saturated at 30 kV of applied voltage. Also collection efficiency of electro spun filters is increased with increasing surface charge potential and surface charge density. But the surface charge potential is decreased by natural decay and it causes deterioration of particle collection efficiency.

• Journal of Convergence for Information Technology
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• v.7 no.5
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• pp.89-93
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• 2017

As the cost of installing and maintaining software on large organizations such as recent companies and schools has increased, software installation and maintenance costs are low, system management is easy, demand for ease of use software solutions has increased. In the reality that special education for service center engineers is required along with the release of various products, training of the software and solution industry is regarded as important. Building Web-based user and system interactive environment, strengthened usability and educational ability effect suitable for engineer level. In the future, research that is familiar with specific software, not successfully combining multiple frameworks, rather than developers, will be increasingly important for research that can achieve optimal performance.

• YAKHAK HOEJI
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• v.58 no.2
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• pp.129-140
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• 2014

Background: As elderly population has been increasing, pharmacists need to possess special knowledge and skills to provide enhanced pharmaceutical care for senior patients. Purpose: This study aims to systematically review on (1) the certified geriatric pharmacists (CGP) system, (2) the curriculum related to geriatric pharmacy education, and (3) the CGP's performance in terms of clinical, economic and humanistic outcomes in the U.S. Method: The information related to CGP system and curriculum was obtained through the official websites of 'American Society of Consultant Pharmacists', 'Commission for Certification in Geriatric Pharmacy' and the selected pharmacy school samples. Articles about on the outcomes of pharmacist-provided cognitive services including Medication Therapy Management were searched through PubMed. Results: To gain the CGP credential, pharmacists need 2-year experience as pharmacist in advance and take the CGP examination. This certification must be renewed every 5 year. Most pharmacy schools provide geriatric-related curriculum through didactic or pharmacy practice classes for pharmacy students and certificate or dual degree in gerontology are given on completion. Most previous outcomes research reported that pharmacists have played a role in yielding favorable results regarding clinical, economic and humanistic outcomes for nursing facilities, hospitals and community pharmacy settings. Conclusion: Considering the organized CGP certification system and concrete educational courses established the basis for pharmacists to exert their ability for senior patients of the U.S., it is suggested to build a geriatric pharmacist credential model for pharmacists to provide the increasing elderly patients with the requisite safe and effective pharmacy care in Korea.

• Journal of the Korea Society of Computer and Information
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• v.10 no.4 s.36
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• pp.93-102
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• 2005

Excessive traffic of P2P applications in the limited communication environment is considered as a network bandwidth problem. Moreover, Though P2P systems search a resource in the phase of search using weakly connected systems(peers' connection to P2P overlay network is very weakly connected), it is not guaranteed to download the very peer's resource in the phase of download. In previous P2P search algorithm (1), we had adopted the heuristic peer selection method based on Random Walks to resolve this problems. In this paper, we suggested an adaptive P2P search algorithm based on the previous algorithm(1) to reform the node distribution rate which is affected in unit peer ability. Also, we have adapted the discriminative replication method based on a query ratio to reduce traffic amount additionally. In the performance estimation result of this suggested system, our system works on a appropriate point of compromise in due consideration of the direction of searching and distribution of traffic occurrence.