A predictive maintenance approach based on real-time internal parameter monitoring

Park, Chulsoon,Moon, Dughee,Do, Namchul,Bae, Sung Moon Springer-Verlag 2016 INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TE Vol.85 No.1

<P>Since continuous real-time components or equipment condition monitoring is not available for injection molding machines, we propose a predictive maintenance approach that uses injection molding process parameters instead of machine components to evaluate the condition of equipment. In the proposed approach, maintenance decisions are made based on the statistical process control technique with real-time data monitoring of injection molding process parameters. First, machine components or equipment of injection molding machines, which require maintenance, is identified and then injection molding process parameters, which may be affected by malfunctioning of the previously identified components, are identified. Second, regression analysis is performed to select the process parameters that significantly affect the quality of the lens and require a high degree of attention. By analyzing the patterns of real-time monitored data series of process parameters, we can diagnose the status of the components or equipment because the process parameters are affected by machine components or equipment. Third, statistical predictive models for the selected process parameters are developed to apply statistical analysis techniques to the monitored data series of parameters, in order to identify abnormal trends. Fourth, when abnormal trends or patterns are found based on statistical process control techniques, maintenance information for related components or equipment is notified to maintenance workers. Finally, a prototype system is developed to show feasibility in a LabVIEWA (R) environment and an experiment is performed to validate the proposed approach.</P>

Predictive Maintenance in Injection Molding Process

ChulSoon Park,DugHee Moon 한국산업경영시스템학회 2014 한국산업경영시스템학회 학술대회 Vol.2014 No.춘계

In this research, we are developing a predictive maintenance model of the injection molding machines based on the prediction of trend of injection molding parameters. At first, we developed an interface method to directly monitor the real-time injection molding parameter data from injection molding machine controller. Second, we identified the principal injection parameters which mainly affect the quality of injection molding products and need to be monitored for maintenance. Third, based on the time series analysis, we developed the prediction models of the principal injection molding parameters, which are identified by previous statistical model to forecast its future patterns/trends and schedule its maintenance point in time. We adopted Nelson’s rules to identify abnormal patterns in predicted data. Finally, we used FTA (fault tree analysis) to relate the injection molding parameters to the parts of the injection molding machine, find out the equipment or parts to be corrected.

Measuring a Value of Contract Flexibility in the Third-Party Warehousing

Chulsoon Park,Bowon Kim 한국경영과학회 2009 Management Science and Financial Engineering Vol.15 No.1

This paper considers the value of warehousing contract under probabilistic demands. We consider a supply chain consisting of a supplier, a retailer and its third-party warehousing partner who provides the warehousing service to the retailer through an outsourcing contract. A typical contract is specified by initial space commitment and modification schedule. The retailer decides the order quantity for the supplier and space commitment for the outsourcing contract. Since there is close relationship between order quantity and space commitment to minimize the total cost including ordering cost, inventory carrying cost, shortage cost, and warehousing cost, we develop an analytical model under probabilistic demands, where the retailer can determine the optimal order size and space commitment level jointly. We found the closed-form optimum for a single-period case and the optimal conditions for a two-period case. To evaluate the value of contract flexibility for the twoperiod case, we compared the total cost under two policies; one with modification, under which the base commitment can be changed at the start of each period and the other without modification. From results of our numerical analysis, we showed that the modification policy is more cost-effective as the variability of demand increases.

Logistics Allocation and Monitoring System based on Map and GPS Information

Chulsoon Park,Larsson Bajracharya 한국산업경영시스템학회 2018 한국산업경영시스템학회지 Vol.41 No.4

In the field of optimization, many studies have been performed on various types of Vehicle Routing Problem (VRP) for a long time. A variety of models have been derived to extend the basic VRP model, to consider multiple truck terminal, multiple pickup and delivery, and time windows characteristics. A lot of research has been performed to find better solutions in a reasonable time for these models with heuristic approaches. In this paper, by considering realtime traffic characteristics in Map Navigation environment, we proposed a method to manage realistic optimal path allocation for the logistics trucks and cargoes, which are dispersed, in order to realize the realistic cargo mixing allowance and time constraint enforcement which were required as the most important points for an online logistics brokerage service company. Then we developed a prototype system that can support above functionality together with delivery status monitoring on Map Navigation environment. First, through Map Navigation system, we derived information such as navigation-based travel time required for logistics allocation scheduling based on multiple terminal multiple pickup and delivery models with time constraints. Especially, the travel time can be actually obtained by using the Map Navigation system by reflecting the road situation and traffic. Second, we made a mathematical model for optimal path allocation using the derived information, and solved it using an optimization solver. Third, we constructed the prototype system to provide the proposed method together with realtime logistics monitoring by arranging the allocation results in the Map Navigation environment.

제조기업의 유연성과 성과 간의 관계

박철순(Chulsoon Park),박상선(Sangsun Park) 한국생산관리학회 2011 韓國生産管理學會誌 Vol.22 No.2

Using survey data of 193 firms from 22 manufacturing industries, we empirically show that manufacturing flexibility is composed of two hierarchical constructs: internal flexibility and external one. A structural equations model provides evidence that an organizational effort to improve the flexibility by a firm enhances the internal flexibility and this improves the external one sequentially. We also study the relationship between external flexibility and two dimensions of business performance – new product development(NPD) and financial performance. The results indicate that the external flexibility not only directly enhances the financial performance but does indirectly through the NPD performance, which confirmed the mediating role of NPD performance between flexibility and financial performance. Finally, we examine the moderating effect of an external variable(quality requirement level of market) on the relationship between manufacturing flexibility and business performances. The results suggest that NPD performance promotes financial performance in the higher level of quality-required market. 본 연구는 제조업의 생산유연성이 단계적으로 구분될 수 있는지와 조직차원의 노력이 어떠한 경로를 통해 생산유연성이 획득되는지를 실증적으로 확인하였다. 또한, 생산유연성이 기업의 여러 성과 차원과 어떤 관계를 갖고 있으며, 그 관계가 시장의 품질 요구 수준에 따른 조절효과의 영향을 받는지도 검증하였다. 본 연구의 대상은 제조업의 22개 업종, 193개의 기업이었으며 분석 결과, (1) 생산유연성은 내부와 외부 생산유연성으로 구분될 수 있으며, 내부 생산유연성이 외부 생산유연성을 향상시킴을 확인하였다. 또한, (2) 생산유연성을 높이려는 조직차원의 노력은 내부 생산유연성을 직접적으로 향상시키지만, 외부 생산유연성을 직접적으로 향상시키지는 않음을 확인하였다. 생산유연성과 성과 간의 관계에서는, (3) 생산유연성이 신제품개발 성과와 재무성과에 직접적인 영향을 미치며, 신제품개발 성과를 매개로 간접적으로 재무성과를 향상시킴을 확인하였다. 특히 (4) 신제품개발 성과와 재무성과간의 관계에 시장의 품질요구수준이 조절효과를 준다는 것을 실증하였다.

중소 제조업의 개방형 혁신이 혁신 성과에 미치는 영향

박철순(Chulsoon Park) 한국생산관리학회 2012 한국생산관리학회지 Vol.23 No.3

본 연구는 중소 제조업의 개방형 혁신 노력이 혁신 성과에 미치는 영향을 살펴보았다. 특히, 개방형 혁신 노력과 혁신 성과 간의 관계를 개방형 혁신 파트너의 만족도가 조절하는지 2009년 중소기업 기술통계조사 자료를 바탕으로 실증하였다. 그 결과, 기업의 내부 혁신 노력과 개방형 혁신 노력 모두 혁신 성과에 긍정적 영향을 주는 것으로 나타났으며, 혁신 파트너와의 만족 수준에 따라서 개방형 혁신 노력이 혁신 성과에 미치는 영향은 다르게 나타났다. 특히 대학과 외국 기업과의 협력 만족도가 유의한 조절 효과를 가졌다. 또, 기업 수명 주기에 따라서 혁신 파트너의 조절 효과는 다른 것으로 확인됐다. 수명 주기의 네 단계 중 성장기와 구조조정기에서만 혁신 파트너의 조절 효과가 유효한 것으로 나타났다. Based on large-sample survey data of small- and medium-sized Korean manufacturing firms, we investigate the relationship between open innovation effort and innovation performance. Specifically, we address a research question whether there exist the moderating role of satisfaction of innovation partners on the relationship. Empirical findings using hierarchical moderated regression analyses suggest that both internal and open innovation effort increase innovation performance. In addition, we find that satisfaction with innovation partners moderates the relationship between the open innovation efforts and innovation performance. We further find that according to the corporate life cycle there is different significance of the moderating role of innovation partners satisfaction. Only at growth and decline stages, the satisfaction of innovation partners significantly moderates the relationship between open innovation efforts and innovation performance.

ERGM을 활용한 자동차산업 공급 네트워크 분석

박철순(Chulsoon Park),강아롬(Ahrom Kang) 한국경영학회 2020 經營學硏究 Vol.49 No.1

This paper analyzes the endogeneous processes that make up the supply network of the automotive industry. A supply network is basically a network in which one company provides goods and information to another. The actual network we observe is a structurally emergent form in which several individual endogenous processes interact. The supply network is a complex adaptation system created by interaction processes. Nevertheless, previous studies have overlooked the interaction of these attributes or the endogenous processes. This is largely due to the limitations of existing research methodologies. Therefore, this study will examine the fundamental aspect of supply network as a complex adaptation system by using a new network analysis method that recognizes interactions in supply network. An Exponential Random Graph Model (ERGM) model was applied to the 2017 Automotive Handbook to explore the underlying processes of the supply network. An ERGM is an novel approach that incorporates endogenous structural effects of network and allows the interactions among various covariates of nodes or links. As a result, the supply network in the automotive industry was basically a chain structure. There were many types of chains that were supplied by suppliers to other companies after its own processing. The basic supply chain did not share intermediaries or skip tiers. In addition, it was difficult to find a structure that directly delivered to customers. In other words, there was no transitivity which can be easily observed in human networks. However, the more intermediaries they share, the more likely they are to have a direct trade relationship. In the case of the purchasers, we confirmed the phenomenon of the rich get richer, which is the possibility of additional transaction when receiving from various companies. As for the suppliers, it is revealed that the possibility of additional delivery is lower as they are delivered to various suppliers due to resource limitations. This study revealed for the first time the endogenous process that constitutes the supply network of the Korean automobile industry. The ERGM model, which recognizes the dependencies between explanatory variables, was used to analyze the fundamental processes of the automotive supply network. Comprehensive inclusion of various explanatory variables to identify the supply relationship in the automotive industry could lead to new conclusions, including the results of previous studies.

기업 간 협업 네트워크의 창발

박철순(Chulsoon Park) 한국경영과학회 2015 한국경영과학회지 Vol.40 No.4

This paper proposes relational capability as a main driver of constructing inter-organizational collaboration networks. Based on social network theory and relational view literature, three components of relational capability are constructed and implemented by an agent-based model. The components include organizational capability, structural capability, and trust between a partner and a focal firm. These three components are updated by two micro mechanisms: structural mechanism and relational mechanism. Structural mechanism is a feedback loop in which the relational capability increases structural capability and vice versa. Relational mechanism is a learning-by-doing process in which a focal firm experiences success or failure of collaboration and the experience increases or decreases cumulative trust in a partner firm. Result of agent-based simulation shows that a collaboration network emerges through interactions of firm’s relational capabilities and the characteristics of emerged networks vary with the contribution of structural capability and trust to relational capability. Specifically, in case structural capability contributes more to relational capability, the average degree centrality and collaboration proportion increases as time passes and enters into an equilibrium state. In that case, almost every firms participated in the network collaborates each other so that the emerged network becomes highly cohesive. In case trust contributes more to relational capability, the results are reversed. In an equilibrium state, the balance of contribution between structural capability and trust makes an emerged network larger and maximizes average degree centrality of the network.

개방형 혁신 네트워크의 동태적 모형

박철순(Chulsoon Park) 한국경영과학회 2015 한국경영과학회지 Vol.40 No.1

Literatures on open innovation have two major limitations. First, either on a firm level or on an industry level did they analyze the open innovation issues. The results of a firm’s innovation can be diffused through the whole network and the firm can learn back from the network knowledge. Prior literatures did not consider the feedback loop among firms and network in which the firms are involved. Second, most open innovation research had a static perspective on firm’s innovation performance. Since the diffusion, spill-over and learning among network members are involved over time, the open innovation is intrinsically dynamic. From the dynamic perspective, we can appreciate the fundamental attributes of the open innovation network which involves diverse firms, research institutes, and universities. In order to overcome the limitations, we suggest a dynamic model for open innovation network. We build an agent-based model which consists of heterogeneous firms. The firms are connected through a scale-free network which is formed by preferential attachment. Through the diverse scenario of simulation, we collect massive data on the firm level and analyze them both on firm and industry level. From the analysis, we found that, on industry level, the overall performance of open innovation increases as the internal research capability, absorptive capacity, and learning curve coefficient increase. Noticeably, as the deprecation rate of knowledge increases, the variability of knowledge increases. From the firm level analysis, we found that the industry-level variables had a significant effect on the firm’s innovation performance lasting through all the time, whereas the firm-level variables had only on the early phase of innovation.

공급네트워크 구조와 재고 비용 성과의 관계

박철순(Chulsoon Park),김성학(Sunghak Kim) 한국생산관리학회 2017 韓國生産管理學會誌 Vol.28 No.1

최근 공급 사슬을 네트워크 관점에서 바라보는 연구가 활발히 진행되고 있음에도 불구하고 아직까지 네트워크 구조와 성 과 간의 관계를 명확히 밝히는데 한계가 있었다. 우리는 이론적 배경을 바탕으로 공급네트워크의 성과가 공급네트워크의 구조에 따라서 달라질 수 있음을 가설로 제시하였다. 이를 검정하기 위해 공급사슬의 대표적인 모형인 비어게임을 네트워 크 형태로 확장한 행위자 기반 모형을 세우고 모의실험을 진행하였다. 구조화된 실험 설계를 통한 모의실험으로 얻은 방 대한 데이터를 분석한 결과 공급네트워크의 구조를 나타내는 지표 중 하나인 평균 경로 길이(average path length)와 성과 간에 역U자 관계가 있음을 밝혔다. 다시 말해, 공급네트워크의 참여 기업 간 논리적 거리가 가깝거나 먼 경우가 논 리적 거리가 중간 정도인 경우에 비해 공급네트워크 재고 비용이 낮게 나타났다. 나아가 이러한 구조와 성과의 역U자 관 계는 리드타임이 길수록, 단위당 재고 유지비용이 클수록 강화됨을 확인했다. 또한, 주문 정책에 따라 역U자 관계가 다르 게 나타남을 보였다. Although supply chain research with a network perspective has been growing fast recently, there are some limitations to verifying a relationship between supply network structure and performance due to the lack of data availability and the complexity of mathematical modeling. Based on a theoretical background, we propose a hypothesis that suggests a curvilinear relationship between supply network structure and performance. In order to test the hypothesis, we develop an agent-based model that extends the Beer Distribution Game from a serial chain to a complex network structure. The model considers different factors that may affect the supply network performance such as lead time, ordering policy, demand pattern, and product cost characteristics. Through deliberately structured simulation experiments, we develop a huge data set at the supply network level. The results show that there is an inverted-U relationship between the average path length (APL) of a supply network and its performance. In other words, supply network performance increases and then decreases as its APL increases. This means that we may achieve minimum supply network costs when the supply network structure is either centralized such as with a hub and spoke structure or decentralized as with a tree structure. Furthermore, the inverted-U relationship between structure and performance is moderated by lead time, ordering policy and unit inventory holding cost. As the overall lead time of supply network members increases or the unit inventory holding cost rises, the slope of the inverted-U shape steepens.