• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.8
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• pp.60-65
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• 2022

This study focuses on the driving control design of an index, which is a key component of a rotary transfer machine that is effective in improving productivity and reducing manufacturing costs by shortening cycle time. Although various index studies have been conducted on the rotation of workpieces such as general-purpose machine tools and tilting indices, the development of an index for rotary transfer machines for transfer is insufficient. The index consists of a body, table, hydraulic cylinder, motor, reducer, and curved coupling. The torque of the table for driving was selected, and the angular velocity and torque pattern were simulated using the motor manufacturer's program. The specifications of the drive motor were determined based on the selected torque.

• Journal of the Korea Society for Simulation
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• v.19 no.4
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• pp.21-29
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• 2010

This research suggests a simulation model regarding the performance analysis of the Heat-Shrink-Tube manufacturing process using a simulation method. To analyze this study, firstly, we have collected the operating data from 'A' automobile parts company. Secondly, we have analyzed the collected data to apply a simulation model. Thirdly, we have developed a simulation model to experiment the process analysis and the line balancing methodology. The proposed simulation model can be executed by various input data without changing the simulation model and the performance of the Heat-Shrink-Tube Manufacturing system can be calculated by this model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.310-315
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• 2017

Automotive waterproof connectors are highly functional parts that must be air-tight in a complex environment. In the LSR multi-cavity injection molding process for manufacturing waterproof connectors, it is important to maintain a uniform curing temperature between the cavities in order to obtain a quality product. For this purpose, we designed the capacity of the cartridge heater differently for each position, and then linked the heat transfer analysis and optimization module to obtain the optimal cartridge heater capacity. As a result of the optimization analysis, the temperature deviation between cavities was decreased from $13.1^{\circ}C$ to $8.1^{\circ}C$ compared with the case in which constant heater capacity was applied, so that the design criterion could be satisfied within a temperature deviation of $10^{\circ}C$ for uniform curing. This study suggests that this method can be applied efficiently to the design of a large area multi-cavity LSR mold heater.

• The Journal of Society for e-Business Studies
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• v.17 no.1
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• pp.53-74
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• 2012

This study developed a method for selection of available human resources for incomingjob allocation that considers factors affecting resource performance in the business process management (BPM) environment. For many years, resource selection has been treated as a very important issue in scheduling due to its direct influence on the speed and quality of task accomplishment. Even though traditional resource selection can work well in many situations, it might not be the best choice when dealing with human resources. Humanresource performance is easily affected by several factors such as workload, queue, working hours, inter-arrival time, and others. The resource-selection rule developed in the present study considers factors that affect human resource performance. We used a Bayesian Network (BN) to incorporate those factors into a single model, which we have called the Bayesian Selection Rule (BSR). Our simulation results show that the BSR can reduce waiting time, completion time and cycle time.

• Journal of KIISE:Databases
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• v.37 no.2
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• pp.121-126
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• 2010

This paper proposes an efficient index scheduling technique for kNN query processing in multiple wireless broadcast channel environment. Previous works have to wait for the next cycle if the required child nodes of the same parent node are allocated in the same time slot on multiple channel. Our proposed method computes the access frequencies of each node of R tree at the server before the generation of the R-tree index broadcast schedule. If they have high frequencies, we allocate them serially on the single channel. If they have low frequencies, we allocate them in parallel on the multiple channels. As a result, we can reduce the index node access conflicts and the long broadcast cycle. The performance evaluation shows that our scheme gives the better performance than the existing schemes.

• Journal of Broadcast Engineering
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• v.10 no.2
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• pp.182-189
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• 2005

In this paper, an asymmetric WDM-EPON transmission scheme is proposed to be used in a high speed access network system, which is required to implement the convergence of broadcast and communication. WDM is used for downstream transmission from OLT to access nodes, satisfying wide bandwidth requirement for broadcasting and various multimedia services. And an EPON scheme, which is cheaper than WDM, is applied to upstream transmission where less bandwidth is required. A transmission test in physical layer was performed successfully and the results are provided. If ONUs are to be used in a home gateway, its protocol should be appropriate to its traffic pattern. Voice is sensitive to a time delay while data is not. A new dynamic bandwidth assignment protocol for PON system, which can cope with various types of data in access network is proposed and its performance is analysed. A maximum cycle time is specified to achieve the QoS of signals sensitive to time delay. And a minimum window is specified to prevent the downstream control signals from uprising. It is shown by simulation that the proposed EPON protocol can provide a better performance than previous ones.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.270-273
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• 2017

Productivity through reduced defects in plastic injection molding and reduced cycle times is a long-standing need in the injection industry. In particular, productivity is very urgent for the domestic injection industry, which is caught between the pursuit of latecomers such as China and technological gap with Germany and Japan which will not be narrowed down. Through 30 years of research and experience in the domestic injection industry, we have found that controlling the surface temperature of injection molds is the key of quality control. There have been various attempts to utilize advanced control techniques such as PID control, but the productivity against leading companies in Germany and Japan is still insufficient. Using Approximation Algorithm - "Knapsack" and "Minimum Makespan Scheduling", We want to show how to efficiently control objects with periodic repetitive data patterns that are difficult to solve with PID control. In addition, We want to propose that the control by Approximation Algorithm is effective enough to improve the productivity of the product by analyzing the data extracted from actual injection site.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.2
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• pp.219-225
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• 2014

An automatic combination and assembly system for phone-camera lens modules was developed. The system enables the assembly of the relative orientation of the individual lenses making up the lens module. Conventional assembly systems assemble a lens module from eight assembly units. The developed system reduces this number to half by combining each lens and a spacer into a single assembly unit. Also, the number of transfer stages for sequential assembly is minimized without increasing the assembly time. Therefore, high productivity and a footprint that is only about 25 % of that of a conventional assembly system can be realized. The system features a modular design to allow it to cope with rapid changes in the market. Only a few components, such as the picker and guide, need to be replaced for changing to a new assembly model.

• Proceedings of the Korea Society for Simulation Conference
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• 1992.10a
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• pp.4-4
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• 1992

본 프로젝트는 수주 오더에 대한 납기 예측과 가공사 Delivery 체계의 전반적 향상을 목적으로 하며, 이에 따른 목표로는 로트 편성의 자동화, 월간, 주간 및 일간 단위의 생산 스케쥴 자동 작성, 원자재 소요량과 재공 및 재고 예측, 설비 부하 분석, 생산 사이클 타임 분석 및 단축이다. 상기의 목표 달성을 위한 가공사 Delivery Scheduling 시스템은 계획용 로트 편성 모델, 실행용 로트 편성 모델, 그리고 가공사 생산 스케쥴 작성을 위한 Simulation 모델로 구성된다. 계획용 로트 편성 모델은 현행의 로트 편성 기준에 따라 미가공 생산의뢰서 전체 물량을 대상으로 로트를 편성하여 이 로트를 염색기에 할당하는 모델이며, 실행용 로트 편성 모델에서는 일일 원사재고, 염색기 고장 등과 같은 실제 조업여건을 고려하여, 작업지시서 발행이 가능한 생산의뢰서 물량에 대하여만 로트 편성을 행한다. 가공사 생산 스케쥴 작성을 위한 Simulation 모델은 계획용 혹은 실행용 로트 편성 모델로부터 얻어지는 로트 편성 결과 또는 로트 번호가 부여된 최종 로트 편성 결과 (재공 로트 포함)를 입력으로 하여 이들 로트가 가공사 생산공정에서 처리되는 상세한 조업을 모의 생산하는 모델이다. 본 시스템은 영업부 및 기획부와 가공부의 사용 목적에 따라 크게 두가지로 사용될 수 있다. 영업부 및 기획부에서는 계획용 로트 편성 모델과 Simulation 모델을 사용하여 수주 오더에 대한 납기 예측 및 원사 수급 계획의 작성에 의사결정 지원을 받을 수 있으며, 가공부에서는 실행용 로트 편성 모델 및 Simulation 모델을 사용하여 상세 가공사 생산 스케쥴의 작성 및 긴급 오더의 처리 등에 관한 의사결정 지원을 받을 수 있다. 본 프로젝트를 통한 효과로는 정확한 생산 스케쥴의 자동 작성 및 스케쥴 작성시간 단축, 납기 예측 및 납기 준수율 향상, 실적관리 향상, 그리고 설비 가동율 분석, 현장관리 등을 위한 기타 유용한 정보제공 등이다.

• Journal of the Korea Institute of Construction Safety
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• v.2 no.1
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• pp.1-8
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• 2019

Recently, as development of building construction technology, height of building continues increase. But, there is no clear ground of service life of tower crane. So, accident in the tower crane continues to occur. In addition to Korea, there is no clear ground for the serive life of tower cranes overseas. For this reason, this study aims to establish the maximum service life of tower crane. Accidents in tower cranes continues to increase, and the cause of the accident is that there are no ground of limitations for service life of tower cranes. Therefore, in this study, the maximum service life of the tower crane was calculated by using the information of the hoisting case of the tower crane to limit the model year of the tower crane. The results of this study are as follows; As the number and time of the hoisting work increases, the maximum service life of the tower crane decreases. In addition, since this study refers to European standards, it is necessary to establish standards for domestic situations. Result of this study, we expect decrease accidents in tower crane. And it is expected that the service life of tower crane will be more clear if this study is developed.