• Safety and Health at Work
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• v.9 no.1
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• pp.42-52
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• 2018

Background: Maintenance operations on-board ships are highly demanding. Maintenance operations are intensive activities requiring high man-machine interactions in challenging and evolving conditions. The evolving conditions are weather conditions, workplace temperature, ship motion, noise and vibration, and workload and stress. For example, extreme weather condition affects seafarers' performance, increasing the chances of error, and, consequently, can cause injuries or fatalities to personnel. An effective human error probability model is required to better manage maintenance on-board ships. The developed model would assist in developing and maintaining effective risk management protocols. Thus, the objective of this study is to develop a human error probability model considering various internal and external factors affecting seafarers' performance. Methods: The human error probability model is developed using probability theory applied to Bayesian network. The model is tested using the data received through the developed questionnaire survey of >200 experienced seafarers with >5 years of experience. The model developed in this study is used to find out the reliability of human performance on particular maintenance activities. Results: The developed methodology is tested on the maintenance of marine engine's cooling water pump for engine department and anchor windlass for deck department. In the considered case studies, human error probabilities are estimated in various scenarios and the results are compared between the scenarios and the different seafarer categories. The results of the case studies for both departments are also compared. Conclusion: The developed model is effective in assessing human error probabilities. These probabilities would get dynamically updated as and when new information is available on changes in either internal (i.e., training, experience, and fatigue) or external (i.e., environmental and operational conditions such as weather conditions, workplace temperature, ship motion, noise and vibration, and workload and stress) factors.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.2
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• pp.213-224
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• 2012

The integrated core network architecture and various mobile subscriber behavior can result in a significant increase of signaling load inside the evolved packet core network proposed by 3GPP in Release 8. Consequently, an authentication signaling analysis can provide insights into reducing the authentication signaling loads and latency, satisfying the quality-of-experience. In this paper, we evaluate the signaling loads in the EPS architecture via analytical modeling based on the renewal process theory. The renewal process theory works well, irrespective of a specific random process (i.e. Poisson). This paper considers various subscribers patterns in terms of call arrival rate, mobility, subscriber's preference and operational policy. Numerical results are illustrated to show the interactions between the parameters and the performance metrics. The sensitivity of vertical handover performance and the effects of heavy-tail process are also discussed.

• Journal of Aerospace System Engineering
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• v.13 no.6
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• pp.36-42
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• 2019

This research illustrates how the simulation environment for operating the simultaneous man/unmanned aerial vehicle teaming is constructed. X-Plane program, HILS for the ducted fan aircraft (unmanned) and CTLS (manned aircraft) with communication devices are interfaced to simulate the basic co-operational flight. The X-plane and HILS can allow operators to experience the maned and unmanned aircraft operation in the airspace on the ground in turn they can perform various simulated missions in advance before the actual flight. For the test purpose, the data link between man/unmanned aircraft and ground control station is examined using C Band and UHF radio channels by the manned aircraft.

• The Journal of Information Systems
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• v.24 no.2
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• pp.163-188
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• 2015

Purpose The healthcare services have drawn so much public attention, and many organizations such as schools and companies require the individuals to undergo the periodic health examination. In general, however, the mass health examination services are not managed in systematic way, and both examinees and medical staffs often experience much inconvenience while preparing, undergoing and managing the services. To address such problems, this paper aims to design the Health Examination Management System (HEMS), an integrated management system for mass health examination operations management, and implement its prototype. Design/methodology/approach First of all, HEMS enables the medical staffs to efficiently collect and manage the examination result data by supporting examination service management. Second, the users can efficiently analyze the cause-and-effect relationships among the examination items by using the visualization tool of HEMS based on the cluster heat map. Finally, the HEMS provides the operational supports for evaluating and managing the service performances. Findings The HEMS indicates that the conventional operations management approaches can be incorporated into the mass health examination services, and it is expected that the proposed system enables the examinees and the medical staffs to participate in such services in more efficient way.

• IEMEK Journal of Embedded Systems and Applications
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• v.12 no.5
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• pp.331-341
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• 2017

This paper presents the sea-trial results of Crabster CR6000 which is a deep-sea walking robot developed by KRISO in 2016. Crabster CR6000 is designed to inspect deep-sea environment rejecting the disturbance on the silent and calm abyssal area. The sea-trial was conducted at the East Sea and the Philippine Sea on December 2016. The Crabster CR6000 undocked successfully from the Shuttle after touchdown on the sea-bed and walked out on the soft sediment soil of the 4,743m seafloor at the fourth diving in the Philippine Sea. The advanced technologies and capabilities of CR6000 were verified from the operational and functional test conducted in the sea-trial. The experimental data acquired from the sea-trial were summarized and the first experience of the deep-sea walking robot was presented in this paper.

• Information Systems Review
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• v.8 no.1
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• pp.223-239
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• 2006

In digital economy, information systems are recognized as the most critical survival factor of companies. Companies must launch and expand business based on information systems either developed newly or adopted as ERP. However, successful information systems operation shall face many realistic problems. Especially most small and medium enterprises experience many difficulties in systems operation or even give up operating information systems due to unexpected operational problems. This paper suggests a framework for effective information systems operation for small and medium enterprises. The framework is designed through case studies, consisting of service framework, auditing framework, and risk management framework. It is expected that the framework contributes to successful information systems operation in small and medium enterprises.

• Journal of Agricultural Extension & Community Development
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• v.8 no.2
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• pp.209-221
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• 2001

The nature of work which is changing has increased the importance of HRD within organization. Also, these changes are making HRD shift its paradigm : from the segregated, closed, operational & administrative, dependent, utilitarian view to the integrative, open, strategic & facilitative, interdependent, generative view. The shifts of the perspective on HRD cause HRD professionals rethink the purpose and definition of HRD, and the role & competency needed to HRD in 21st century. The findings which are drawn through literature review and researcher’s intuition based on a long field experience are as follows. First, The function of HRD has recently been much more important then that of the past. Second, There is no consensus over the conceptual identity of HRD. Nonetheless, it is apparent that the preferred activities of the HRD function is performance improvement. Third, It is too difficult that we should define clearly the role & competency of HRD because of diverse perspectives on them. But we find much evidence converging to support the fact that the role & competency of HRD should be extended from the sole focus on training & development to adding the additional role & competency of change agent, who includes planning, implementing, and managing change.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.5
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• pp.680-687
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• 2018

Because of its predictability of the energy cycle and huge scale power output, the ocean energy from tidal power utilization has always received attention as a great energy source, even though its development cost, including the embankment construction, is so much higher than that of any other energy source. Nevertheless, nowadays many projects are being planned on account of institutional support from the government and the recent advance of construction technology. In Korea, the new industry field operating and managing the tidal power plant has already opened. But we are facing a number of problems for optimal operation of tidal power plant that are a lack of operation experience and a skill of professional management and others. This paper suggests a novel way to determine the starting head of power generation by generating power comparison method For this new method, the paper discusses many factors including changing the volume of the basin, the number of operating turbines and gates and forecasting the tidal amplitude and the characteristic curve of turbine and gate. Finally we verified that it can increase about 2% an annual power generation compared with the conventional method using the original operational function made in the plant design process.

• Journal of the Korean Operations Research and Management Science Society
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• v.23 no.2
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• pp.187-200
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• 1998

This paper presents an original approach for solving short-term power scheduling in extended power system with two fuels in a unit and a limited fuel using Lagrangian relaxations. The underlying model incorporates the full set of costs and constraints including setup, production, ramping, and operational status, and takes the form of a mixed integer nonlinear control problem. Moreover, the mathematical model developed includes two fuels in a unit and a limited fuel, regulation reserve requirements of prespecified group of units. Lagrangian relaxation is used to disaggregate the model by generator into separate subproblems which are then solved with a nested dynamic program including empirical knowledges. The strength of the methodology lies partially in its ability to construct good feasible solutions from information provided by the dual. Thus, the need for branch-and-bound is eliminated. In addition, the inclusion of two fuels in a unit and a limited fuel provides new insight into the limitations of current techniques. Computational experience with the proposed algorithm indicates that Problems containing up to 23 units including 8 unit used two fuels and 24 time periods can be readily solved in reasonable times. Duality gaps of less than 4％ were achieved.

• IE interfaces
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• v.18 no.1
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• pp.73-81
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• 2005

Injection molding has been widely used in producing plastic parts in large quantities. However, its productivity mainly depends on the expertise and experience of skilled workers because of the difficulty and complexity to determine a robust injection molding condition which is not influenced by the minor operational variation of an injection molding machine and produces good parts continuously. This study analyzes the defect types of the parts and proposes a support system to assist users in determining the robust process condition. The support system calculates the start condition from the information of an injection mold, the injection molding machine, the resin used, and the part. Through the iterative step which updates the condition using the defect information of the part tested, users can obtain the initial condition which produces the part without any problem for the first time. The support system also assists users in obtaining the robust condition from the initial condition using the technique of experimental design. To prove the validity of the support system, this study implements it in the control panel of the injection molding machine.