• Journal of the Korean Society of Food Culture
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• v.31 no.2
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• pp.161-169
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• 2016

This study examined co-worker relationship on of life between employees of contract foodservice in general hospital. Contract foodservice managed general hospitals surveyed from 1 October 2015 to 31 October 2015. A total of 230 questionnaires (cook-30 questionnaires, nutritionist-50 questionnaires, cook's helper-150 questionnaires) were distributed, and 177 questionnaires were used for the study. As a result, the quality of life of employees contract foodservice general hospital was composed of sub-factors (employee engagement, stress at work, home-work interface, working condition, general well-being). co-worker relationship was composed of sub-factors (cooperative co-worker relationship, competitive co-worker relationship). Causal relationship between variables was through regression analysis, and significant results were shown. ooperative co-worker relationship had an effect on employee engagement, stress at work, working condition and general well-being. competitive co-worker relationship.

• Proceedings of the Korean Statistical Society Conference
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• 2002.11a
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• pp.197-201
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• 2002

The healthy worker effect is an important issue in occupational epidemiology. We proposed a new statistical method to test the relationship between exposure and time to death in the presence of the healthy worker effect. In this study, we considered the healthy worker hire effect to operate as a confounder and the healthy worker survival effect to operate as a confounder and an intermediate variable. The basic idea of the proposed method reflects the length bias-sampling caused by changing one's employment status. Simulation studies were also carried out to compare the proposed method with the Cox proportional hazards models. According to our simulation studies, both the proposed test and the test based on the Cox model having the change of the employment status as a time-dependent covariate seem to be satisfactory at an upper 5% significance level. The Cox models, however, are inadequate with the change, if any, of the employment status as time-independent covariate. The proposed test is superior in power to the test based on the Cox model including the time-dependent employment status.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.160-161
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• 2016

In tall building construction, lift car for worker lifting is a critical factor for construction productivity. To reduce worker lifting time, existing researches have been conducted on lift car planning. While, research on lift car operation is insufficient. For the efficient reduction of worker lifting time, lift car operation control is needed with lift car planning. Therefore, this research suggests operation control model of lift car to reduce worker lifting time. According to the result of a model test, the operation control model contributes to reasonable reduction of worker lifting time.

• Journal of Labour Economics
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• v.35 no.3
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• pp.1-28
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• 2012

We measure a worker's analyzability by how correctly he grasps its causes when a problem occurs, comprehensiveness by how much he understand the overall process of his firm, and flexibility by how frequently unusual situations occur at his job. After controling firm-specific fixed of fandom effects, his age, tenure, position, and rank, the characteristics increase a worker's wage. A worker who grasps correctly the causes of problem is paid more by 5.2% than a worker who scarcely does. A worker who understands the overall process of his firm is paid more by 2.52% than a worker who understands roughly the process of his team or department. A worker whose job is mew one by one is paid more by 2.98% than a worker whose job is routine and repetitive.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.4
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• pp.318-328
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• 2003

Numerical simulation using computational fluid dynamics (CFD) is performed to calculate the velocities and temperature profiles of air in adjacent to a worker within the individual local air conditioning system. The calculation domain is the space of ㄴ between walls and a worker in the climate room. The fresh air is supplied from the three different inlets located on the right, left and center wall in the climate room. In this study, the calculated data of velocities and temperature profiles of air in the nearest the skin of a worker are used to calculate the PMV (Predicted Mean Vote) for evaluation of thermal comfort of a worker in the local air conditioning system. Because the data of veto-cities temperature profiles of air in adjacent to a worker and the PMV of a worker are the design parameters of the local air conditioning system. The results of calculation show that the fresh air velocity and injection position are closely related to the PMV value. In individual air condition system of ㄴ, the appropriate PMV are obtained when the fresh air velocity and position are 1.0 m/s, throat of a worker and are 1.5 m/s, head of a worker, respectively. The method of numerical calculation is effective to obtain the optimum velocity and position of the fresh air for optimum the PMV and energy saving in individual local air conditioning system.

• Industrial Engineering and Management Systems
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• v.10 no.3
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• pp.197-202
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• 2011

In traditional production lines, such as assembly lines, each worker is usually assigned to a particular fixed work, and decreasing the task to master the assigned work is valuated. However, when an imbalance exists between workers' speeds, if a worker delays the overall work in the production line, the production rate of the particular line will also decrease. To avoid this problem, the "Self-Balancing Production Line" was introduced. In this type of production line, each worker is assigned work dynamically, and when specific conditions are satisfied, production remains balanced. Characteristics of these lines that can be preempted at any place have already been analyzed by some researchers. A previous paper examined the situation in which only a single worker can process one machine and cannot preempt processing, and the improved policy of an ordinary selfbalancing production line, which specifies which stations workers can process and how workers can behave. This policy achieveda high production rate with only four stations and two workers (Buzacott, 2002). In that paper, worker processing stations and the behavior of a specific worker were limited, andthe paper focused only on specific stations and workers. Therefore, it is not applicable to any worker sequence. In this paper, we focus on other ways to decrease cycle time. In this kind of line, a worker processes at his or her speed. Therefore, if a worker is assigned stations according to his or her speed, the line can decrease cycle time. To do so, we relax the assumptions of this type of line and set a new condition. Under these conditions, we compare our results to the results of previous papers.

• 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.

• International Journal of Reliability and Applications
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• v.3 no.2
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• pp.61-80
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• 2002

Tree-harvesting worker data of 508 separate worker accidents are analyzed and an exploratory approach taken. The worker accident data cover a sample of five years. The scope of the study was the southeastern United States of America. As might be hypothesized, the chainsaw was the most hazardous type of tree-harvesting equipment. It accounted for 55％ of the tree-harvesting accidents. Most chainsaw accidents resulted in injuries to the lower extremities and were more frequent among younger employees. The probability of one or more chainsaw accidents occurring in any 30-day period was approximately 0.856. Chainsaw accidents were more likely to occur in late morning and early afternoon. We used statistical tools such as Pareto charts, c-charts and Ishikawa diagrams. Such tools are useful in diagnosing the root-cause of tree-harvesting worker accidents and help in developing preventive safety programs. Recommendations to help improve the quality of information of accident data collected by insurance companies and others are briefly given. The strategy and culture of continuous process improvements are stressed.

• IE interfaces
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• v.22 no.3
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• pp.263-277
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• 2009

This research deals with a task assignment problem to worker group which consists of one master and one assistant. Each task must be assigned to only one worker group and it is possible to make a pair of each master and each assistant to organize a worker group. A worker group may have more than one task assigned to it, but the workloads of each worker group must be balanced within the allowable range. This problem can be formulated mathematically using the Mixed Integer Programming(MIP), where the objective function is to minimize the total assignment cost. A two phase heuristic algorithm is suggested in order to find approximate solutions. The first phase is to obtain an initial solution, where the initial assignment is performed to follow the workload adjustment. In the second phase, the solution is improved through the repeated process of the exchange and the assignment adjustment. Numerical experiments have been performed to evaluate the performance of the heuristic algorithm.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2012.04a
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• pp.147-150
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• 2012

This study restoration worker for dispersion relay in R-Type fire alarm system. Restoration worker very good instrument for an fire system inspector. When inspector check for fire system someone need reset for fir system to normal state. This chain of action is frequent and troublesome. In this case, If we can automatic reset for fire system it's restoration worker. This paper settlement on the problem for reset fire system. Design, make grabber for restoration worker. The test offer proof possibility restoration worker.