• Journal of the Ergonomics Society of Korea
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• v.32 no.5
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• pp.475-480
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• 2013

Objective: In this study, virtual reality was adopted to consider ergonomic factors in yacht design. Virtual human which is the same actual human was created in virtual environment using Digital Human Modeling which has been used in the manufacturing communities to design better workplaces and maximize the safety of workers. Background: During the past 40 years yachting has expanded from being, generally speaking, a minority sport - too expensive for the large majority of people - into a major recreational activity practiced by millions all over the world. Many new yacht designs have appeared and number of professional, as well as amateur designers has increased steadily. But they had not considered ergonomic factors in yacht design. Method: Worker's posture, traffic line and workload had been analyzed in sailing yacht. After the caution level was evaluated, we pointed out clues which had high workload and interference. To reduce workload, we applied ergonomic principles for improving working conditions and environments in Digital Human Model. Results: We found the space problems and workload of postures. Conclusion: (1) Unnatural posture of crews was sustained. (2) Workload that occurs in the human body was overloaded. (3) Crew's work space was very narrow. Application: This study will be applied the new ergonomic design of yacht.

• Journal of the Korea Society for Simulation
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• v.4 no.2
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• pp.1-16
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• 1995

The performance of a computer system depends on the system architecture and workload, and the high performance required in many applications can be achieved by the scalability of the system architecture and workload. This paper presents scalable workload, a performance metric of scalable speedup and hierarchical modeling for the scalable computer system as well as the development of the object-oriented simulator spmplC++ Which is an advanced C++ version of the discrete event-driven simulation environment smplE. In addition, this paper presents two examples of applying scalable speedup, hierarchical modeling and simulator smplC++ to analyze the performance effect of the sclcbility in a multiprocessor system and a network-based client/server system.

• Journal of the Korea Safety Management & Science
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• v.18 no.1
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• pp.131-140
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• 2016

This present study tested whether job stress mediates the relationship between workload and safety behavior of members in organization. In addition, we hypothesized trust in leader/coworkers functions as moderator between not only the workload-job stress link, but also the job stress-safety behavior link. In order to investigate the hypotheses, 841 employees in various fields of companies were sampled. Using structural equation modeling(SEM), we conducted moderated mediation model analysis which elaborately investigated the significance of our hypotheses. The results indicated that job stress mediated the link between workload and safety behavior of members. In addition, the relationship between workload and job stress was moderated by trust in leader/coworkers. Moreover trust in leader/coworkers moderated the job stress-safety behavior linkage. The implications and limitations of our study and suggestions for future research were discussed.

• Journal of the Korea Society of Computer and Information
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• v.21 no.1
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• pp.125-129
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• 2016

In this paper, we propose an efficient dynamic workload balancing strategy which improves the performance of high-performance computing system. The key idea of this dynamic workload balancing strategy is to minimize execution time of each job and to maximize the system throughput by effectively using system resource such as CPU, memory. Also, this strategy dynamically allocates job by considering demanded memory size of executing job and workload status of each node. If an overload node occurs due to allocated job, the proposed scheme migrates job, executing in overload nodes, to another free nodes and reduces the waiting time and execution time of job by balancing workload of each node. Through simulation, we show that the proposed dynamic workload balancing strategy based on CPU, memory improves the performance of high-performance computing system compared to previous strategies.

• Journal of the Korea Society for Simulation
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• v.12 no.4
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• pp.103-111
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• 2003

A distributed sewer cluster system is a cost-effective system to provide a service application for clients with reliable, scalable, available, and fault-tolerant features. In order to provide high quality services, it is necessary to evaluate service performances, tune the server system, and analyze performances. In this paper, we propose a simulator to generate workloads based on statistic configuration according to estimated application traffics, apply workload scheduling algorithms, and evaluate the simulation results. We introduce the simulator design modelling and architecture. By using flexible parameters, the simulator is able to generate various patterns of workloads with different statistics, and configure system environments such as the number of server nodes, system resources considered, and their capacities. With this simulator, we introduce two scenarios: one is to find appropriate thresholds for the best performance of cluster system, and the other is to find the suitable scheduling algorithm for workload characteristics of service applications.

• Proceedings of the Korea Society for Simulation Conference
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• 2003.11a
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• pp.27-34
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• 2003

A distributed server cluster system is a cost-effective system to provide a service application for clients with reliable, scalable, available, and fault-tolerant features. In order to provide high quality services, it is necessary to evaluate service performances, tune the server system, and analyze performances. In this paper, we propose a simulator to generate workloads based on statistic configuration according to estimated application traffics, apply workload scheduling algorithms, and evaluate the simulation results. We introduce the simulator design modelling and architecture. By using flexible parameters, the simulator is able to generate various patterns of workloads with different statistics, and configure system environments such as the number of server nodes, system resources considered, and their capacities. With this simulator, we introduce two scenarios: one is to find appropriate thresholds for the best performance of cluster system, and the other is to find the suitable scheduling algorithm for workload characteristics of service applications.

• Journal of Information Processing Systems
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• v.16 no.1
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• pp.132-144
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• 2020

Cloud computing is an emerging technology based on the concept of enabling data access from anywhere, at any time, from any platform. The exponential growth of cloud users has resulted in the emergence of multiple issues, such as the workload imbalance between the virtual machines (VMs) of data centers in a cloud environment greatly impacting its overall performance. Our axis of research is the load balancing of a data center's VMs. It aims at reducing the degree of a load's imbalance between those VMs so that a better resource utilization will be provided, thus ensuring a greater quality of service. Our article focuses on two phases to balance the workload between the VMs. The first step will be the determination of the threshold of each VM before it can be considered overloaded. The second step will be a task allocation to the VMs by relying on an improved and faster version of the meta-heuristic "simulated annealing (SA)". We mainly focused on the acceptance probability of the SA, as, by modifying the content of the acceptance probability, we could ensure that the SA was able to offer a smart task distribution between the VMs in fewer loops than a classical usage of the SA.

• Journal of the Korea Society for Simulation
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• v.12 no.3
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• pp.69-81
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• 2003

To manage a cluster of distributed server systems, a number of management aspects should be considered in terms of configuration management, fault management, performance management, and user management. System performance monitoring and reporting take an important role for performance and fault management. In this paper, we present distributed system architecture modeling of a performance monitoring and reporting tool. Modeling architecture of four subsystems are introduced: node agent, data collection, performance management & report, and DB schema. The performance-related information collected from distributed servers are categorized into performance counters, event data for system status changes, service quality, and system configuration data. In order to analyze those performance information, we use a number of ways to evaluate data corelation. By using some results from a real site of a company and from simulation of artificial workload, we show the example of performance collection and analysis. Since our report tool detects system fault or node component failure and analyzes performances through resource usage and service quality, we are able to provide information for server load balancing, in short term view, and the cause of system faults and decision for system scale-out and scale-up, in long term view.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1999.05a
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• pp.135-144
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• 1999

A major concern in Concurrent Engineering is the control and management of workload in a period of process. As a general rule, leveling the peak of workload in a certain period is difficult because concurrent processing is comprised of various processes, including overlapping, paralleling and looping. Therefore, workload management with resource constraints is so beneficial that effective methods to analyze design process This study presents a procedure to transform the IDEF3 process model into the precedence logic network model for more useful assessment of the process. This approach is expected to facilitate resolving resource constrained scheduling problems more systematically in Concurrent Engineering environment.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.51
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• pp.231-240
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• 1999

A major concern in Concurrent Engineering is the control and management of workload in a period of process. As a general rule, leveling the peak of workload in certain period is difficult because concurrent processing is comprised of various processes, including overlapping, paralleling looping and so on. Therefore, the workload management with resource constraints is so beneficial that effective methods to analyze design process are momentous. This study presents the Timed Petri Nets approach of precedence logic networks, and provides an alternative for users to analyze constraint processes to resolve conflicts of resources. Another approach to Continuous Time Markov Chain using Stochastic Petri Nets is also proposed. These approaches are expected to facilitate resolving resource constrained scheduling problems more systematically in Concurrent Engineering environment.