• Journal of Applied Reliability
• /
• v.14 no.2
• /
• pp.122-128
• /
• 2014

In this paper, we consider the periodic preventive maintenance model for a repairable system following the expiration of extended warranty under replacement-repair warranty. Under the replacement-repair warranty, the failed system is replaced or minimally repaired by the manufacturer at no cost to the user. Also, under extended warranty, the failed system is minimally repaired by the manufacturer at no cost to the user during the original extended warranty period. As a criterion of the optimality, we utilize the expected cost rate per unit time during the life cycle from the user's perspective. And then we determine the optimal preventive maintenance period and the optimal preventive maintenance number by minimizing the expected cost rate per unit time. Finally, the optimal periodic preventive maintenance policy is given for Weibull distribution case.

• 제어로봇시스템학회:학술대회논문집
• /
• 1989.10a
• /
• pp.250-254
• /
• 1989

This study is to develop the interactive program for work-cell layout of SCAPA type robot using PC. To make the program interactively, we made use of the software which have the function of menu, dialog box, and graphic. By using the mouse, we can progress the program quickly and easily. It has 2 1/2 dimension and provides that one can layout the elements(robot, peripheral device, and etc.), create the work path, and calculate the robot cycle time. By comparing with cycle times of any number of work-cell layout for the same work, we can evaluate work-cell layout and select one work-cell layout to be considered optimal one which has the least cycle time.

• 한국기계연구소 소보
• /
• s.19
• /
• pp.117-123
• /
• 1989

This study is to develop interactive program for work-cell layout of SACARA type robot by using PC. To make this program interactively, we made use of the software which has the function of menu, dialog box, and graphic. By using the mouse, we can progress this program quickly and easily. It has 2Y2 dimension and provides that one can layout elements (robot, peripheral device, and etc.), create work path, and calculate cycle time of working robot. By comparing with cycle times of any number of work-cell layout for same work, we can evaluate work-cell layout. Finally, we can select one work-cell layout to be considered optimal one which has the least cycle time.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.13 no.1
• /
• pp.76-84
• /
• 2003

Now days, It is based on GIS and GPS, it can search for the shortest path and estimation of arrival time by using the internet and cell phone to driver. But, even though good car navigation system does not create which is the shortest path when there average vehicle speed is 10 -20 Km. Therefore In order to reduce vehicle waiting time and average vehicle speed, we suggest optimal green time algorithm using fuzzy adaptive control, where there are different traffic intersection length and lane. In this paper, it will be able to forecast the optimal traffic information, estimation of destination arrival time, under construction road, and dangerous road using internet.

• KEPCO Journal on Electric Power and Energy
• /
• v.6 no.1
• /
• pp.59-64
• /
• 2020

Scheduling of electric vehicles and optimizing for charging waiting time have been critical. Meanwhile, it is challengeable to exploit the fluctuating data from electric vehicles in real-time. We introduce an optimal routing algorithm and a simulator with electric vehicles obeying the Poisson distribution of the observed information about time, space and energy-demand. Electric vehicle routing is updated in every cycle even it is already set. Also, we suggest an electric vehicle routing algorithm for minimizing total trip time, considering a threshold of the waiting time. Total trip time and charging waiting time are decreased 34.3% and 86.4% respectively, compared to the previous algorithm. It can be applied to the information service of charging stations and utilized as a reservation service.

• Science of Emotion and Sensibility
• /
• v.17 no.2
• /
• pp.85-90
• /
• 2014

The purpose of the study is to develop self-management system that people can enhance physical and psychological health through repeating by themselves to relieve work-related stress. The regular respiration can help homeostasis of heart to maintain. Also the effect can be stabilized from irregular heart rhythm by work-related stress. People have optimal respiration cycle to stabilize heart rhythm and repeat training using their RSP(respiration) time including expiration and inhalation. This system is not only offering optimal respiration training service but also finding optimal respiration cycle. The adults who have stress from work participated in verification experiment. This study expects to help those people who are workers related to call center jobs in emotional labor can relieve their stress. It can also help to enhance their own health and increase their work efficiency.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.38 no.1
• /
• pp.167-174
• /
• 2018

This study attempts to construct a model of optimal headway, focusing on a practical applicability to bus transit operation. Examining the existing bus operation and scheduling plans imposed by Busan City, we found that the plans failed to reasonably take into account such realities as varying traffic and operational conditions. The model is thus developed to derive the hourly optimal headway by routes satisfying the real-world conditions: varying hourly demand and cycle time, applying the model to routes 10 and 27 as examples. To do so, we collect big-dataset generated by smart card system and BIMS (Bus Inforamtion Management System). It is expected that the results of this study wil be a basis for further refined research in this field as well as for preparing practical timetables for bus operation.

• Journal of Information Processing Systems
• /
• v.7 no.1
• /
• pp.1-16
• /
• 2011

With the increasing number of vehicles in use in our daily life and the rise of traffic congestion problems, many methods and models have been developed for real time optimisation of traffic lights. Nevertheless, most methods which consider real time physical queue sizes of vehicles waiting for green lights overestimate the optimal cycle length for such real traffic control. This paper deals with the development of a generic hybrid model describing both physical traffic flows and control of signalised intersections. The firing times assigned to the transitions of the control part are considered dynamic and are calculated by a simplified optimisation method. This method is based on splitting green times proportionally to the predicted queue sizes through input links for each new cycle time. The proposed model can be easily translated into a control code for implementation in a real time control system.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10a
• /
• pp.258-262
• /
• 1990

Several optimum control algorithms have been proposed to minimize the robot cycle time by velocity scheduling. Most of these algorithms assume that the dynamic and kinematic characteristics of a manipulator are fixed. This paper presents the study of a minimum-time optimum control for robotic manipulators considering parameter changes. A complete set of solutions for parameter identification of the robot dynamics has been developed. The minimum-time control algorithm has been revised to be updated using estimated parameters from measurements.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.11 no.17
• /
• pp.39-46
• /
• 1988

This Paper is concerned with a man-multi machine assignment problem to minimize idle time. Assuming different types of semi-automatic machines with deterministic service-processing time, the problem approaches by sequential dependent one operator can handle several machines, where determine optimal range the cost of idle labor and machine time is to be minimized in preparing a work schedule. The Procedure, to establish man-machine assignment model, and it's results are: (1) Objective function to minimize opportunity loss cost, which is happened by idle time, is verified recursive process through heuristic method. (2) The algorithm, is programmed by BASIC language for personal computer, and a numerical example is given to illustrate the heuristic algorithm. This study will be helpful to enhance productivity of Shopflooras a result of increasing the efficiencies of both operator and machine.