• Journal of the Korean Operations Research and Management Science Society
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• v.40 no.4
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• pp.145-156
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• 2015

Incorporation of individual learning and forgetting behaviors within worker-task assignment models produces a mixed integer nonlinear program (MINLP) problem, which is difficult to solve as a NP hard due to its nonlinearity in the objective function. Previous studies commonly assume homogeneity among workers in workforce scheduling that takes account of learning and forgetting characteristics. This paper expands previous researches by considering heterogeneous individual learning/forgetting, and investigates the impact of worker heterogeneity in initial expertise, steady-state productivity, learning and forgetting on system performance to assist manager's decision-making in worker-task assignments without tackling complex MINLP models. In order to understand the performance implications of workforce heterogeneity, this paper examines analytically how heterogeneity in each of the four parameters of the exponential learning and forgetting (L/F) model affects system performance in three cases : consecutive assignments with no break, n breaks of s-length each, and total b break-periods occurred over T periods. The study presents the direction of change in worker performance under different assignment schedules as the variance in initial expertise, steady-state productivity, learning or forgetting increases. Thus, it implies whether having more heterogenous workforce in terms of each of four parameters in the L/F model is desired or not in different schedules from the perspective of system productivity measurement.

• The Journal of Society for e-Business Studies
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• v.13 no.3
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• pp.153-171
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• 2008

Center of labor power was moved from physical labor to knowledge labor on modern knowledge society comparing with past industrial age, but dramatic result is not appearing in knowledge worker's productivity. "Peter F. Drucker" called "father of modern business management" is essential factor of knowledge labor based on expert, performance, concentration, own administration official, second half of life. And studied about task, reform, autonomy, education, quality, relation of information communication that is knowledge worker's productivity determinant factor. As research result, was expose that relativity is high by performance>concentration>own administration official>expert, second half of life in essential factor of knowledge labor. Specially, all productivity determinants and effect factor were performance by result to knowledge worker. Therefore, knowledge worker can expect formation's target and performance though search and practical use of continuous information are achieved in own field.

• Journal of Korean Society of Forest Science
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• v.105 no.4
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• pp.441-448
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• 2016

The purpose of this study was to broaden our knowledge on the productivity and costs of felling operation in three different harvesting methods(whole tree, tree-length and cut-to-length). Felling was conducted in three different harvesting methods with two workers who have different work experiences. Worker A and B have had felling experiences for about 5 years and 15 years, respectively. Felling productivity in whole tree method was $10.3m^3/SMH$ for worker A and $12.7m^3/SMH$ for worker B. Felling costs for worker A and B were $2,066won/m^3$ and $2,201won/m^3$, respectively. Although felling productivity of worker B in whole tree method was higher than worker A, felling costs of worker A were similar to worker B because the wage of worker B was more expensive than the wage of worker A (p>0.05). In tree-length method, felling cost of worker B were cheaper than that of worker A. Felling productivity and cost in tree-length method were $2.2m^3/SMH$ and $9,890won/m^3$ for worker A and $3.3m^3/SMH$ and $8,459won/m^3$ for worker B, respectively (p<0.05). In cut-to-length method, felling productivity and cost were $2.3m^3/SMH$ and $9,584won/m^3$ for worker A and $3.0m^3/SMH$ and $9,395won/m^3$ for worker B, respectively. Felling productivity of worker B was higher than that of worker A(p>0.05). Our preliminary results found that harvesting methods and worker's experiences highly affect on the productivity and costs of felling operations. These results should be useful for forest managers when planning cost-effective harvesting operations.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1999.12a
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• pp.759-768
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• 1999

In this paper, we developed a simulation model of a car parts assembly line to improve the system performance such as worker's utilization balancing, productivity. This simulation model has been developed using QUEST, a true 3D discrete event simulation pakcage that is designed for modeling and analysis of manufacturing systems. We have suggested the results obtained to improve the system performances of an existing production line.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.30
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• pp.35-41
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• 1994

Improve of productivity is a key for the development of a company, which can be pursued in the apect of material factor and personal factor. And the motives of worker for their job is more influenced by the chance of incentive compensation or self-development than by participation in management and safety of their post ect. Contingency theory is one of the theories that cope with this study Therfore, this study describes incentive compensation for satisfying worker desire related company's productivity, and be presented to the aspect of contingency accounting.

• Journal of the Korea Society for Simulation
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• v.11 no.4
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• pp.69-80
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• 2002

This study deals with the productivity improvement on a flow production system with the consideration of line-balancing. In a flow production system, similar product models are produced on a same assembly line, the predefined process order and the limitation of total worker number. The system can be increased the work-in -process(WIP) inventory and the worker's idle time. In this study, the worker assignment model is developed to assign evenly workload of process to each product model in such a manner that each process has the different number of worker. This worker assignment model is the mathematical model that determines worker number in each process such that the idle time of processes is reduced and the utilization of worker is improved. We use a simulation technique to simulate the production line proposed by the mathematical model and apply real production line. With the result of simulation, this study analyzes the propriety of production line and proposes the alternatives of new production line

• Journal of the Korean Society of Safety
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• v.22 no.6
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• pp.74-80
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• 2007

In manufacturing industry, machining technology for metal cutting processes has been considered traditional and economic dimensions such as production cost, production time and quality of a final product. However, owing to governmental regulations and the change of owner's cognizance, the safety of the workers becomes important in those fields. In this paper, the operation planning system developed as a key component of CAPP(Computer Aided Process Planning) system is introduced for milling operations. The main issue in the system is to determine the cutting conditions in achieving a balanced consideration of productivity and worker's safety. For this reason, the system performs the modification process of standard cutting conditions to satisfy those requirements. Related to machining safety in metal cutting, representative and habitual mistakes that operators perform without considering carefully the characteristic of machine or work piece are described and then the detailed algorithm and functions of the developed system is introduced and discussed.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.336-338
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• 2015

This research is to propose an applicable framework for real-time health surveillance and safety monitoring at construction sites. First this study aims at finding (1) a framework for health surveillance that is likely to benefit employers and employees in the industry, (2) a valid way to identify factors or conditions with potential health concerns that can occur under particular work conditions, (3) An effective way to apply wireless/mobile sensors to construction workers using real-time/live data transmission methods, and (4) A relationship between a worker's vital signs and job site environment. Biosensors for physiological response and devices for weather/work related data are to collect real-time data. Relationships between jobs and physiological responses are analyzed and factors that touched particularly contributing to certain responses are identified. When data are incorporated with tasks, factors affecting tasks can be identified to estimate the magnitude of the factors. By comparing work and normal responses possible precautionary actions can be considered. In addition, the study would be lead to improving (1) trade-specific dynamic work schedules for workers which would be based on various factors affecting worker health level and (2) reevaluating worker productivity with health status and work schedule, thereby seeking ways to maximize worker productivity. Through a study, the paper presents expected benefits of implementing health monitoring.

• Journal of Labour Economics
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• v.31 no.3
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• pp.47-74
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• 2008

Following two pioneering works, Medoff and Abraham(QJE 1980; JHR 1981) and Flabbi and Ichino(LE 2001) which use performance rating of personnel data as individual worker's productivity, this study replicates their analysis using a Korean large firm's personnel data(2000, male white collar workers). According to their methods through Mincerian earnings function, and multinomial logit model that links the distribution of wages and performance ratings, we find that seniority wages appeare continuously even if individual worker's productivity is controlled. Therefore we conclude that incentive or deferred compensation theory is more suitable than human capital theory.

• Journal of the Korean Dietetic Association
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• v.3 no.1
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• pp.63-73
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• 1997

This study was conducted to evaluate the industry foodservice management practices and to suggest guidelines for the effective foodservice management. The survey for the analysis was conducted through the questionnaires to dietitians. They were divided into two groups : the site color worker and the blue color worker. The questionnaires were received for a response rate of 73.2%. Statistical data analysis was completed using the SAS programs for descriptive analysis, $x^2$ test, T-test, F-test, and Fisher's LSD. The results of the study can be summarized as follows : 1) The level of education of dietitians and food cost in the employee feeding operations for the blue color worker was lower than the employee feeding operations for the white color worker. 2) The labor productivity indices were not significantly different according to types of workers. But in the employee feeding operations for the blue color worker, full-time foodservice employees worked more than 10.7 hour per week than their counterpart. This indicates the full-time foodservice employees in the employee feeding operations for the blue color worker performed more loaded work compared to the employee feeding operations for the white color worker. 3) Equipped rate of facilities in the employee feeding operations for the blue color worker was low especially in the food preparation and cooking processes.