• Journal of the Korean Operations Research and Management Science Society
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• v.22 no.4
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• pp.115-131
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• 1997

The problem addressed in this paper is to minimize the deviations of workloads assigned to worker and to maximize the total utilizations(degree of skill) between workers and machines simultaneously. Each worker can handle the set of machines with the different degree of skill and each machine has the workloads needed to be processed. Also, each worker has to be assigned to at least one machine with the minimum workload deviation. This problem can be formulated as a preemptive goal programming with generalized assignment constraints. The proposed algorithm consists of two phases. First, a capacitated circulation network is constructed to assign the workers to machines with the maximum total utilizations while considering workloads balance. Then, a refinement process is applied to the split machines to satisfy the feasibility condition. The real industrial application in a plastic extrusion manufacturer is included along with several computational experiments.

• Journal of the Korean Operations Research and Management Science Society
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• v.29 no.4
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• pp.175-187
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• 2004

We consider the simultaneous selection of part routes for multiple part types in Flexible Manufacturing Systems (FMSs). Using an optimization framework we investigate two alternative route assignment policies. The one, called routing mix policy in the literature, specifies the optimal proportion of each part type to be produced along its alternative routes, assuming that the proportions can be kept during execution. The other one, which we propose and call pallet allocation policy, partitions the pallets assigned to each part type among the routes. The optimization framework used is a nonlinear programming superimposed on a closed queueing network model of an FMS which produces multiple part types with distinct repeated visits to certain workstations. The objective is to maximize the weighted throughput. Our study shows that the simultaneous use of multiple routes leads to reduced bottleneck utilization, improved workload balance, and a significant increase in the FMS's weighted throughput, without any additional capital investments. Based on numerical work, we also conjecture that pallet allocation policy is more robust than routing mix policy, operationally easier to implement, and may yield higher revenues.

• IE interfaces
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• v.14 no.4
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• pp.394-402
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• 2001

In this study, we deal a spatial scheduling system for the block painting process in the shipbuilding industry. In general, the spatial scheduling for the block painting process is a very complicated task. Because spatial allocation of each block in blasting and painting cells is considered simultaneously. Thus the spatial scheduling for the block painting process is the problem of planning and control of operation, which arises in shipyard. This system is developed for blocks to meet the delivery date given by the shipyard production planning system, to maximize space utilization of blasting and painting cells and to balance workload among working teams. And it has been tested using actual scheduling data from a shipyard and successfully applied in a paint shop in a shipbuilding company.

• Journal of the Ergonomics Society of Korea
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• v.25 no.4
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• pp.1-7
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• 2006

The purpose of this study is to develop an efficient algorithm for the management of the shift schedule in nuclear power plants in consideration with the ergonomic criteria and the regulatory codes. The ergonomic criteria considered are the work hours, overtime-work frequency and working time, start and finishing time of works, allocation of rest times and duty-offs, rotating of shifts, etc. to comply with the regulations such as the Labor Standard Act, the ILO Convention No. 171, 178, "the detailed content of a periodic safety review," enforcement regulations 19-2 of the Atomic Energy Act. The developed algorithm for the shift schedule program adopts a heuristic method to minimize the difference the workload for shift workers in nuclear power plants.

• IEMEK Journal of Embedded Systems and Applications
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• v.16 no.3
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• pp.113-117
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• 2021

The data gathering delay and the network lifetime are important indicators to measure the service quality of wireless sensor and actuator networks (WSANs). This study proposes a dynamically cluster head (CH) selection strategy and automatic scheduling scheme of collectors for prolonging the network lifetime and shorting data gathering delay in WSAN. First the monitoring region is equally divided into several subregions and each subregion dynamically selects a sensor node as CH. These can balance the energy consumption of sensor node thereby prolonging the network lifetime. Then a task allocation method based on genetic algorithm is proposed to uniformly assign tasks to actuators. Finally the trajectory of each actuator is optimized by ant colony optimization algorithm. Simulations are conducted to evaluate the effectiveness of the proposed method and the results show that the method performs better to extend network lifetime while also reducing data delay.

• Journal of Korea Multimedia Society
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• v.11 no.7
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• pp.914-927
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• 2008

Grid database management systems are used for large data processing, high availability and data integration in grid computing. Furthermore the grid database management systems are in the use of manipulating the queries that are sent to distributed nodes for efficient query processing. However, when the query processing is concentrated in a random node, it will be occurred with imbalance workload and decreased query processing. In this paper we propose a load balancing method for query processing based on cache Management in grid databases. This proposed method focuses on managing a cache in nodes by cache manager. The cache manager connects a node to area group and then the cache manager maintains a cached meta information in node. A node is used for caching the efficient meta information which is propagated to other node using cache manager. The workload of node is distributed by using caching meta information of node. This paper shows that there is an obvious improvement compared with existing methods, through adopting the proposed algorithm.

• Journal of Korean Academy of Rural Health Nursing
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• v.18 no.1
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• pp.57-71
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• 2023

Purpose: This study aims to provide primary data for policy alternatives by identifying the problem of the nursing workforce shortage. Methods: For quantitative data, 446 questionnaires were analyzed. The mean and standard deviation were used for content description. ANOVA analysis and Scheffe? test were used to compare the differences according to the hospital level. For qualitative data, 1:1 in-depth and group interviews were conducted for six participants. Results: The factors nurses prioritized when choosing a workplace were salary, commuting distance, and work-life balance. Clinical nurses cited low wages, heavy workloads, and burnout as the most considerable difficulties in performing their duties. Factors influencing nurse's turnover intention were low wages, unmanageable workload, and rotation to unwanted departments in that order. New nurses tend not to apply to small-medium-sized hospitals, experienced nurses in their 30s-40s leave hospitals due to childcare and shift work difficulties, and nurses in their 50s and older tend to move to nursing homes rather than acute hospital settings. Conclusion: In this study, wage and workload were mentioned as the most critical factors in nurses' workplace selection, job performance difficulties, and turnover intention, so it is necessary to pay attention to this aspect when improving treatment for nurses.

• Journal of the Korean Geographical Society
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• v.44 no.6
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• pp.813-832
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• 2009

As accessibility to health-care service in less populated rural areas is geographically limited and demand for public health-care by the aging is increasing, a new approach for health-care service such as a home care service is becoming more popular. For a home care service, health-care personnels directly visit to location of health-care clients. Such changes in provision of health services require developing innovative and scientific approaches for efficient allocation of health resources and managing services by public health-care organizations. The purpose of this study is to formulate a location model for visiting health-care districting for the rural elderly and to develop an Automated Zoning Procedure (AZP) to solve this model. Mobility, workload balance and contiguity criteria are considered in the model. Three different objective functions are evaluated; 1) minimizing the sum of network distance between the unit areas in a district, 2) maximizing spatial interaction between the unit areas in a district, and 3) minimizing tour distance that visits each unit area exactly once in a district. The AZP for solving the model is developed and applied to a rural area. The application results demonstrate that the AZP can generate different districting systems for each objective functions.

• Korean Journal of Labor Studies
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• v.24 no.1
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• pp.229-260
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• 2018

Workaholism refers to a state in which work is the center of self, a state in which other life other than work is deemed worthless, and a state in which one feels that his or her life ends when things get lost. There are concerns that South Korea's work-centered institutions, cultures and long-time labor practices expose workers to workaholism. This study identifies the prevalence of workaholism and its risk factors among workers using a representative sample from Korean Labor and Income Panel Study. The results of empirical analysis of the wide range of workaholism showed that 7.0% of Korean workers were work-addicts. Male, workers working long hours, daily workers, employers, the self-employed were more likely to be work-addicts. Those who think that workload is high beyond regular working hours are more likely to be work-addicts. These results were also confirmed by regression analysis. It suggests that policies to shorten working hours and strengthen job and income stability can reduce the risk of workaholism and balance between work and life.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.3
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• pp.275-286
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• 2015

In this paper, we propose a practical method for setting up a daily production plan which can operate semiconductor fabrication factories more stably and linearly by determining work in process (WIP) targets and movement targets. We first adjust cycle times of the operations to satisfy the monthly production plan. Second, work in process (WIP) targets are determined to control the production progress of operations: earliness and tardiness. Third, movement targets are determined to reduce cumulated differences between WIP targets and actual WIPs. Finally, the determined movement targets are modified through a simulation model which considers capacities of the equipments and allocations of the WIPs in the fab. The proposed daily production planning method can be easily adapted to the memory semiconductor fabs because the method is very simple and has straightforward logics. Although the proposed method is simple and straightforward, the power of the method is very strong. Results from the shop floor in past few periods showed that the proposed methodology gives a good performance with respect to the productivity, workload balance, and machine utilization. We can expect that the proposed daily production planning method will be used as a useful tool for operating semiconductor fabrication factories more efficiently and effectively.