• Journal of Industrial Convergence
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• v.3 no.1
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• pp.19-31
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• 2005

This paper deals with the sequencing problem in the operation of the manufacturing systems with the constraint of buffer capacity. Some of studies for this theme have been progressed for several years. And then most of them considered only one objective, such as maximum lateness, machine utilization, makespan, mean flowtime and so on. This study deal with two objectives of the delivery for customers and the idle time of machines for producers. For the decision of sequence, the utility function is used. The developed heuristic algorithm presents a good solution. Through a numerical example, the procedures of the job sequencing is explained.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.7
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• pp.535-540
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• 2016

The braking device in railway vehicles decelerates or stops the train by dissipating the thermal energy converted from kinetic energy into the air. Therefore, the brake system is crucial for safety. In this paper, we performed a study on an electromechanical brake actuator using an electrical motor as an alternative to pneumatic air cylinders to reduce the idle running time in braking, which subsequently increases braking distance, and to ensure reliable response characteristics. Especially, to analyze the response characteristics of the electromechanical brake actuator, we measure the delay time, response time and power consumption compared to the air cylinder. It is confirmed that the electromechanical brake actuator can reduce reaction time by 0.1 seconds (Braking Action) and 0.46 seconds (Brake Release) compared to the air cylinder.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.11
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• pp.5271-5289
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• 2016

On large-scale data analysis platforms deployed on cloud infrastructures over the Internet, the instability of the data transfer time and the dynamics of the processing rate require a more sophisticated data distribution scheme which maximizes parallel efficiency by achieving the balanced load among participated computing elements and by eliminating the idle time of each computing element. In particular, under the constraints that have the real-time and limited data buffer (in-memory storage) are given, it needs more controllable mechanism to prevent both the overflow and the underflow of the finite buffer. In this paper, we propose an auto regulated data provisioning model based on receiver-driven data pull model. On this model, we provide a synchronized data replenishment mechanism that implicitly avoids the data buffer overflow as well as explicitly regulates the data buffer underflow by adequately adjusting the buffer resilience. To estimate the optimal size of buffer resilience, we exploits an adaptive buffer resilience control scheme that minimizes both data buffer space and idle time of the processing elements based on directly measured sample path analysis. The simulation results show that the proposed scheme provides allowable approximation compared to the numerical results. Also, it is suitably efficient to apply for such a dynamic environment that cannot postulate the stochastic characteristic for the data transfer time, the data processing rate, or even an environment where the fluctuation of the both is presented.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.5 s.335
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• pp.63-72
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• 2005

This paper describes a new approach for the operating system level power management to reduce the energy consumed in the IO devices in a robot platform, which provides various functions such as navigation, multimedia application, and wireless communication. The policy proposed in the paper, which was named the Energy-Aware Job Schedule (EAJS), rearranges the jobs scattered so that the idle periods of the devices are clustered into a time period and the devices are shut down during their idle period. The EAJS selects a schedule that consumes the minimum energyamong the schedules that satisfy the buffer and time constraints. Note that the burst job execution needs a larger memory buffer and causes a longer time delay from generating the job request until to finishing it. A prototype of the EAJS is implemented on the Linux kernel that manages the robot system. The experiment results show that a maximum $44\%$ power saving on a DSP and a wireless LAN card can be obtained with the EAJS.

• Applied Chemistry for Engineering
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• v.10 no.5
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• pp.748-753
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• 1999

In gelcasting process of the Si powder slurry mixed with acrylamide monomers, it was characterized the effects of chemical parameters such as monomers and additives(polymerization initiator, catalyst and dispersant), Si powder and humidity at drying on processing parameters such as viscosity and idle time as well as on shrinkage and mechanical strength of green bodies. Generally, idle time decreased as initiator and catalyst amounts were increased, but rather depended on initiator. Idle times of the slurries greatly decreased to less than 1/2 time of the premix solutions in which gelation was delayed at higher MBAM portion as a crosslinking monomer. And fluidity of the slurries became worse at greater than 0.6 wt % dispersant. The green bodies showed only less than 7% of linear shrinkage without crack and distortion when dried for longer than 300 hrs under 98% humidity. Typically, the dried bodies containing 40, 50 vol % of Si powder displayed 64 and 36 Mpa in average, respectively.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.6
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• pp.465-476
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• 2005

In this paper, we propose a new dynamic reconfiguration method using application-level checkpointing in a grid computing environment with Cactus and Globus. The existing dynamic reconfiguration methods have been dependent on a specific hardware and operating system. But the proposed method performs a dynamic reconfiguration without supporting specific hardwares and operating systems and, an application is programmed without considering a dynamic reconfiguration. In the proposed method, the job starts with an initial configuration of Computing resources and the job restarts including new resources dynamically found at run-time. The proposed method determines whether to include the newly found idle sites by considering processor performance and available memory of the sites. Our method writes the intermediate results of the job on the disks using system-independent application-level checkpointing for real-time visualization during the job runs. After reconfiguring idle sites and idle processors newly found, the job resumes using checkpointing files. The proposed dynamic reconfiguration method is proved to be valid by decreasing total execution time In K*Grid.

• Industrial Engineering and Management Systems
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• v.15 no.4
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• pp.364-373
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• 2016

Disassembly is one of the important activities in treating with the product at the End of Life time (EOL). Disassembly is defined as a systematic technique in dividing the products into its constituent elements, segments, sub-assemblies, and other groups. We concern with a Fuzzy Disassembly Line Balancing Problem (FDLBP) with multiple objectives in this article that it needs to allocation of disassembly tasks to the ordered group of disassembly Work Stations. Tasks-processing times are fuzzy numbers with triangular membership functions. Four objectives are acquired that include: (1) Minimization of number of disassembly work stations; (2) Minimization of sum of idle time periods from all work stations by ensuring from similar idle time at any work-station; (3) Maximization of preference in removal the hazardous parts at the shortest possible time; and (4) Maximization of preference in removal the high-demand parts before low-demand parts. This suggested model was initially solved by GAMS software and then using Genetic Algorithm (GA) in MATLAB software. This model has been utilized to balance automotive engine disassembly line in fuzzy environment. The fuzzy results derived from two software programs have been compared by ranking technique using mean and fuzzy dispersion with each other. The result of this comparison shows that genetic algorithm and solving it by MATLAB may be assumed as an efficient solution and effective algorithm to solve FDLBP in terms of quality of solution and determination of optimal sequence.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2910-2915
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• 2008

This paper was investigated the behaviors of the engine and combustion phenomena for various LPG compositions in the semi-return type system, which is not recircurated to LPG tank through furl rail, applied LPi engine during a cold idle condition and including a cold start of the engine. Cyclic HC and NOx emissions were measured at exhaust port to examine their formation mechanical and reduction mechanical with fast response gas analyzers. Various ignition timing is experimented to study the characteristics of combustion phenomena, HC/NOx emissions during fast idle. Also, this study was investigated start delay time, cylinder pressure, HC/NOx emissions, Mass Fraction Burned, starting time to evaluate performance of transient cold startability. Compared to the return type system, the semi-return type system have advantages in point of production cost and equivalent performance of engine starting time and pressure settling time.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.172-174
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• 2021

In the existing industry, maintenance was carried out in the form of preventive maintenance such as occurrence of unnecessary idle time due to limited monitoring and maintenance. However, with the advent of the Fourth Industrial Revolution, real-time monitoring is possible in many industries including mining, manufacturing, oil and gas, and commercial agriculture, and it is desired to minimize idle time due to maintenance. In particular, there is a growing interest in predictive maintenance that can reduce costs and maximize operational efficiency by predicting and maintaining a failure before equipment and equipment fail. In this study, we look at the predictive maintenance technology that can verify the abnormal condition of the equipment of the smart factory in advance and monitor the abnormal condition in real time.

• Journal of applied mathematics & informatics
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• v.5 no.1
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• pp.1-12
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• 1998

We consider G/M/1 queues with multiple vacation disci-pline where at the end of every busy period the server stays idle in the system for a period of time called changeover time and then follows a vacation if there is no arrival during the changeover time. The vaca-tion time has a hyperexponential distribution. By using the methods of the shift operator and supplementary variable we explicitly obtain the queue length probabilities at arrival time points and arbitrary time points simultaneously.