• Proceedings of the Korean Society for Quality Management Conference
• /
• 2006.11a
• /
• pp.31-37
• /
• 2006

The objective of this research is to select the most effective technique from task related techniques(motion & time study, job redesign, physical environment improvement) for improving work efficiency in shipbuilding enterprise. This study consists of several principal steps. The first step is to design critical criteria in evaluating work efficiency in shipbuilding enterprises. The second step is to develop sub-criteria of the critical criteria. The third step is to develop a four level AHP(Analytic Hierarchy Process)structure using the critical criteria, sub-criteria and techniques from task related techniques. The fourth step is to develop the pairwise comparison matrix by each level of AHP structure, which was based on survey data collected at the H heavy industry. And the last step is to select the most effective technique from task related techniques using AHP analysis. The result of AHP analysis has shown clear difference in priority among task related techniques in terms of work efficiency of the shipbuilding enterprise: The reduction of normal time has more importance than the reduction of allowance time, motion & time study techniques are most important for the reduction of normal time, physical environment improvement is most important for the reduction of allowance time as well.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.30 no.2
• /
• pp.67-74
• /
• 2007

The objective of this research is to select the most effective technique among task related techniques(motion & time study, job redesign, physical environment improvement) for improving work efficiency in shipbuilding enterprise. This study consists of several principal steps. The first step is to design critical criteria in evaluating work efficiency in ship-building enterprises. The second step is to develop sub-criteria of the critical criteria. The third step is to develop a four level AHP(Analytic Hierarchy Process) structure using the critical criteria, sub-criteria and techniques among task related techniques. The fourth step is to develop the pairwise comparison matrix at each level of AHP structure, which was based on survey data collected at the H heavy industry. And the last step is to select the most effective technique among task related techniques using AHP analysis. The result of AHP analysis has shown clear difference in priority among task related techniques in terms of work efficiency of the shipbuilding enterprise: The reduction of normal time is more important than the reduction of allowance time in improving of the work efficiency. Motion & time study is the most important technique for the reduction of normal time, and physical environment improvement is the most important technique for the reduction of allowance time as well.

• Earthquakes and Structures
• /
• v.9 no.4
• /
• pp.875-891
• /
• 2015

Earthquake can occur anywhere in the world and it is essential to design important members in special structures based on maximum possible forces that can be produced in them under severe earthquake. In addition, since the earthquake is an accidental phenomena and there are no similar earthquakes, therefore the possibility of strong earthquakes should be taken into account in earthquake-resistant design of important structures. Based on this viewpoint, finding the critical acceleration which maximizes internal forces is an essential factor in structural design. This paper proposes critical excitation method to compute the critical acceleration in design of important members in special structures. These critical accelerations are computed so that the columns' internal shear force at the base of the structure at each time step is maximized under constraints on ground motion. Among computed critical accelerations (of each time step), the one which produces maximum internal shear force is selected. A numerical example presents to show the efficiency of critical excitation method in determining the maximum internal shear force and base moment under variety of constraints. The results show that these method can be used to compute the resonant earthquake which have large enough effective duration of earthquake strong motion (between 12.86 sec to 13.38 sec) and produce the internal shear force and base moment for specific column greater than the same value for selected earthquakes in constructing the critical excitation (for different cases about 2.78 to 1.29 times the San Fernando earthquake). Therefore, a group of them can be utilized in developing the response spectrum for design of special structures.

• Korean Medical Education Review
• /
• v.20 no.1
• /
• pp.44-50
• /
• 2018

The purpose of this study was to investigate factors associated with the critical thinking ability of nursing students at the individual and school levels. The study adopted a descriptive design and recruited 465 nursing students from four nursing schools from November 2014 to September 2015 through convenience sampling. The Clinical Critical Thinking Skill Test was used to measure critical thinking ability, and the data were analyzed with the SAS ver. 9.4 program (SAS Institute Inc., Cary, NC, USA) for descriptive statistics, t-test, analysis of variance, and multi-level model. The results showed that clinical practicum experience (${\beta}=-0.72$, p=0.025), taking critical thinking courses (${\beta}=0.63$, p=0.010), and taking simulation courses (${\beta}=0.56$, p=0.035) improved critical thinking ability in the individual level model. In the school level model, the interaction effect between the years of clinical practice done by the student and the presence of full-time clinical instructors was significant (${\beta}=1.29$, p=0.011). These results suggest that critical thinking ability improves with the more years of clinical practice individual nursing students have, and this improvement is greater with the presence of full-time clinical instructors in the school. Therefore, it is recommended that nursing students undergo critical thinking and simulation courses to develop their critical thinking ability, and dedicated clinical instructors in nursing schools should play a vital role.

• Korean System Dynamics Review
• /
• v.7 no.2
• /
• pp.81-96
• /
• 2006

Real-Time Enterprise concept comes out as an alternative to reduce the increasing uncertainty of the business environment recently. And lots of companies want to get Real-Time concept into their organizations. However, studies on RTE are not sufficient yet, from defining to realizing it. Thus, this study defines RTE activities with the RTE definition of Gartner and derives RTE critical success factors. During this study, system thinking is used to make interactions of RTE variables clear, and causal maps, generated by system thinking, are applied to derive CSF.

• Journal of the Korean Data and Information Science Society
• /
• v.22 no.5
• /
• pp.989-998
• /
• 2011

Cloud computing provides computation, software, data access, and storage services that do not require end-user knowledge of the physical location and configuration of the system that delivers the services. Cloud computing providers have setup several data centers at different geographical locations over the Internet in order to optimally serve needs of their customers around the world. One of the fundamental challenges in geographically distributed clouds is to provide efficient algorithms for supporting inter-cloud data management and dissemination. In this paper, we propose a group quorum system (GQS)-based dissemination for improving the interoperability of inter-cloud in time-critical event dissemination service, such as computing policy updating, message sharing, event notification and so forth. The proposed GQS-based method organizes these distributed clouds into a group quorum ring overlay to support a constant event dissemination latency. Our numerical results show that the GQS-based method improves the efficiency as compared with Chord-based and Plume methods.

• Journal of the Korean Data and Information Science Society
• /
• v.23 no.6
• /
• pp.1259-1269
• /
• 2012

Cloud computing has rapidly become a new infrastructure for organizations to reduce their capital cost in IT investment and to develop planetary-scale distributed applications. One of the fundamental challenges in geographically distributed clouds is to provide efficient algorithms for supporting inter-cloud data management and dissemination. In this paper, we propose a geographic group quorum system (GGQS)-based hybrid algorithm for improving the interoperability of inter-cloud in time-critical event dissemination service, such as computing policy updating, message sharing, event notification and so forth. The proposed algorithm first organizes these distributed clouds into a geographic group quorum overlay to support a constant event dissemination latency. Then it uses a hybrid protocol that combines geographic group-based broad-cast with quorum-based multicast. Our numerical results show that the GGQS-based hybrid algorithm improves the efficiency as compared with Chord-based, Plume an GQS-based algorithms.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.7 no.5
• /
• pp.948-953
• /
• 2006

This study presents a statistic method to estimate the salient time of critical success factors for successful business. Generally, the importance of the facts is flexible along with changes of business circumstance. Also, the change of business circumstance is affected by time. Thus, the importance of facts is change through the time. This study, based on Roger's diffusion of innovations theory suggests a precise estimating method to cognitional timeliness of the critical success factors in technology-based Industry.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.17 no.12
• /
• pp.1095-1105
• /
• 2005

Numerical analysis has been carried out to investigate transient turbulent convective heat transfer in a vertical tube for supercritical water near the thermodynamic critical point. Heat transfer and fluid flow in the tube we strongly coupled due to the large variations of thermodynamic and transport properties such as density, specific heat, and turbulent viscosity. As pressure in the tube approaches to the critical pressure, the properties variation with time becomes larger. Heat transfer coefficient rapidly decreases along the tube near the pseudocritical temperature at the tube wall for $P_R<1.2$. Stanton number variation with time is largely reduced in the region of gas-like phase in comparison with Nusselt number. Turbulent viscosity ratio close to the wall increases near the pseudocritical temperature and it gradually decreases with time.

• Journal of Institute of Control, Robotics and Systems
• /
• v.15 no.12
• /
• pp.1240-1245
• /
• 2009

The throughput characteristics of the cluster tool with dual blade robot are analyzed. Using equipment's cycle time chart of the equipment, simple analytic form of the throughput is derived. Then, several important throughput characteristics are analyzed by the throughput formula. First, utilization of the process chamber and the robot are maximized by assigning the equipment to the process whose processing time is near the critical process time. Second, rule for selecting optimal number of process chambers is suggested. It is desirable to select a single process chamber plus a single robot structure for relatively short time process and multi process chambers plus a single robot, namely cluster tool for relatively long time process. Third, throughput variation between equipments due to the wafer transfer time variation is analyzed, especially for the process whose processing time is less than critical process time. And the throughput and the wafer transfer time of the equipments in our fabrication line are measured and compared to the analysis.