Xianda Kong

Optimal worker assignment with two special workers in a limited-cycle model with multiple periods

This study investigates the properties of the optimal assignment of two special workers in a limited-cycle model with multiple periods. Due to the competition among enterprises, meeting the scheduled delivery date becomes a necessity. In most arbitrary cases, the result and efficiency of a certain period of a production cycle are influenced not only by the risks that exist in the current period but also by the risks that existed in the foregoing ones. Moreover, the risk itself is also greatly affected by the risks that existed in the earlier periods. This kind of model is called a limited-cycle model with multiple periods. In this paper, we consider the properties of the optimal worker assignment that minimises the total expected risk in a limited-cycle model with multiple periods. This study is useful in describing the properties of the optimal worker assignment theoretically and determining an optimal cycle time.

Virtual reference feedback tuning using closed-loop step response data in frequency domain

The paper gives a controller tuning method using a Virtual Feedback Tuning (VRFT) approach in the frequency domain. While the original VRFT uses a data-driven performance index based on input/output data directly, the proposed one derives a frequency domain performance index based on the Fourier transformation of one-shot experimental input-output data. The frequency domain performance index makes the optimal pre-filter be straightforwardly designed without using the spectral density of the collected input signal. Hence, the proposed ones outperforms the original ones when the input and output data is collected from the closed loop step response. The effectiveness of the proposed method is illustrated through a numerical example.

Optimal Worker Assignment under Limited-Cycled Model with Multiple Periods - Consecutive Delay Times is Limited

Strictly keep delivery date is the life of the manufacturing enterprise indefinitely. Especially in the developing countries such as China, labor-intensive enterprise is still the mainstay industry. As a result, assembly line is widely used as a manufacturing process for reducing costs and production time. However, laborer is the main factor of production speed in such a labor-intensive enterprise. So because of the various working capacity of worker, one work process may delay or idle, and this will influence the rear several processes. This unforeseeable consecutive delay of process may influence the whole manufacturing production. So we build a model, called as limited- cycled model with multiple periods (LCMwMP), to assume evaluating the influence risk. In order to minimize the risk, the assignment of the workers, especially untrained worker is focused on. In previous researches, rules of optimal worker assignment with two kinds of workers were proposed in which one, two and three untrained workers exist. As it is, the non-limited consecutive delay time is not allowed in the fact world. In this paper, we deal with an assembly line as LCMwMP model when there are two kinds of workers, who are distinguished by workers efficiency. We consider an optimization problem with three untrained workers, specially consider limited consecutive delay times as twice or three times, for comparing with the previous research in which consecutive delay times is not limited. And, by some numeral experiments, we will conclude several rules of optimal assignment.

Property of worker allocation optimization with two professional workers in limited-cycle multiple periods

In this paper, we deal with an assembly line with limited-cycle multiple periods with two kinds of workers. Skills of workers are assumed to be different. We consider an optimization problem for finding an allocation of workers to the line that minimizes total expected cost satisfying the demand. Then we propose a theorem of the property of the optimal worker allocation and discuss the other properties in conditions.