Hanil Jeong

A batch splitting method for a job shop scheduling problem in an MRP environment

The job shop scheduling problem has been a major target for many researchers. Unfortunately though, most of the previous research was based on assumptions that are different from the real manufacturing environment. Among those distorted assumptions, two assumptions about set-up time and job composition can greatly influence the performance of a schedule. First, most of the past studies ignored the impact of the before-arrival set-up time. If we know the sequence of operations in advance, we can obtain an improved schedule by preparing the setup before a job arrives. Secondly, most of the past studies assumed that a job consists of only a single part, that is a batch of size one. However, if we assume that a job consists of a batch size greater than one, as in many real manufacturing environments, then we can obtain an improved schedule because we can fill up the idle times of machines with jobs which have smaller processing times by splitting the original batches. However, the number of job orders may the...

A batch splitting heuristic for dynamic job shop scheduling problem

The job shop scheduling problem has been a major target for many researchers. Unfortunately, though, most of the past studies assumed that a job consists of only a single part. If we assume that a job consists of a batch as in many real manufacturing environment, then we can obtain an improved schedule. However, then, the size of the scheduling problem would become too large to be solved in practical time limit. So, we proposed an algorithm to get an improved schedule by splitting the original batch into smaller batches, and thereby can meet the due date requirement, and adapt to unexpected dynamic events such as machine failure, rush order and expediting.

Using business process specifications and agents to integrate a scenario-driven supply chain

In todays increasingly competitive global market, most enterprises place great stress on reducing order fulfillment costs, minimizing time-to-market and maximizing product quality. The desire of businesses to achieve these goals has seen a shift from a make-to-stock paradigm to a make-to-order paradigm. The success of the make-to-order paradigm requires robust and efficient supply chain integration and implementation in the business-to-business (B2B) environment. Recent Internet-based approaches to this problem have enabled efficient and effective information sharing among trading partners (i.e., customers, manufacturers and suppliers). Here we present an integration framework for supply chain operations among trading partners in the B2B environment. A supply chain scenario is formed, for which an integration framework is proposed by using the concepts of business process specifications (BPS) and agent technology. The BPS with message choreographies among the trading partners is detailed by using a modified unified modelling language (UML). The behaviour of the enterprise applications within each trading partner is modelled as agent concepts by using Petri-nets, which depict how the enterprise applications respond to external events specified in the BPS. The concepts and models proposed in this paper should provide the starting point for the formulation of a structured approach to B2B supply chain integration and implementation.

Grid enabled MRP process improvement under distributed database environment

The material requirement planning (MRP) process is crucial when software packages, like enterprise resource planning (ERP) software, are used in the production planning for manufacturing enterprises to ensure that appropriate quantities of raw materials and subassemblies are provided at the right time. Whereas little attention has been paid to the architectural aspects of MRP process in academic studies, in practice, reports are often made of its time consuming characteristics due to intensive interactions with databases and difficulty in real time processing. This paper proposes a grid enabled MRP process in a distributed database environment and demonstrates the performance improvement of the proposed process by a simulation study.

A Model and Analysis of the Bullwhip Effect Using a SCOR-Based Framework

Increasing dynamics are making efficient management of the supply chain difficult. The bullwhip effect is known to be a major source of this inefficiency so there is a considerable amount of literature analyzing its causes. However, the reported outcomes are not comparable because they consider different business environments and make different assumptions regarding operative processes. We propose a SCOR (Supply-Chain Operations Reference-model)-based framework for modeling and analyzing the bullwhip effect so that practitioners can evaluate the performance of their supply chain, and establish a strategy to improve its performance.

Production Planning and Control in Korea : with Emphasis on the Role of Industrial Engineers

Korea Productivity CenterThis is a report on the history and current status of production planning and control activities in South Korea with regard to Industrial Engineers’ (IEs’) role. One of the main characteristics of Korean global companies is that they make good use of IEs not only in their production but also in higher strategic fields like supply chain management. In these companies it is well demonstrated that instead of adding small part of IE skills to traditional engineers, it is much more competitive to have IEs work with them as a team since IEs are fully proficient in every kind of productivity and quality improvement tools. It is also observed that IEs become more productive when they have good domain knowledge in their own industries like semi-conductor, automobile, telecommunications, steel, shipbuilding, etc. So teaching the basics for manufacturing processes to IE students seems very important for their future career development.

A Framework for Enhancing Responsiveness in Sales Order Processing System Using Web Services and Ubiquitous Computing Technologies

This study attempts to enhance the responsiveness of enterprises by adjusting the delivery dates taking into account of the production and delivery schedules in a supply chain. To enhance responsiveness, we suggest a due-date assignment method and re-negotiation process for a sales order processing system. The due-date assignment method is designed with the concept of categorized customers’ priorities and the re-negotiation process is designed with the concept of the partial delivery and due-date delay allowances. Usually, the due-dates have been considered as customer-assigned exogenous parameters or fixed endogenous variables set by manufacturers. However, those are customary in some industries, e.g. semi-conductor manufacturing, that customers often request changes for their delivery dates after placing an order if something unexpected happens. From these observations, we also propose a new architecture of responsive sales order processing system based on Web Services and Ubiquitous Computing technologies for reliable real-time information.

Design of a Software Component Bank for Distribution

Recently, component-based software development technology is recognized as a new methodology that can overcome the problems of the traditional methodology at developing the software. It removes the problems by supporting fast development, easy maintenance, good quality, easy creation/upgrade of application, low cost, etc. It also creates new software business area such as business component developer, sales and distribution vendors. Many research institutes report that the market related with software component industry will grow with high rate. For the highly growing component market, a component distribution model is necessary to activate developing components, to promote the utilization, and to support distribution of them. In this paper, we propose a component distribution model through the requirement analysis. We also propose the UML model based on the requirement analysis, developed a prototype. We presented the developed system using several graphic user interfaces.

Camera Placement in Smart Cities for Maximizing Weighted Coverage With Budget Limit

This paper addresses the camera placement problem for smart cities in 3-D space and proposes a heuristic algorithm that maximizes the weighted coverage rate while satisfying the budget constraint. We first discuss about the quantization of surveillance target and camera locations into discrete grid points and the setting of the weights of target grid points. We then present the visibility analysis with field of view in consideration of occlusions and different camera specifications. Based on these characteristics and constraints, we formulate the camera placement problem and propose a new heuristic algorithm called collaboration-based local search algorithm, which incorporates the local search into collaborative allocation. We evaluate the performance of the proposed algorithm in comparison with the greedy algorithm, binary genetic algorithm, and binary particle swarm optimization through simulation experiments with small and large problem sets. The simulation results show that the proposed algorithm outperforms the three existing algorithms in terms of the average weighted coverage rate and computation time.

Business Process Patterns for Integrated Supply Chain Planning

Todays competitive global market makes most enterprise endeavor to specialize their business areas, and co-operate with trading partners in supply chain by forms of collaboration, information and business process sharing. However, even the supply chain plan generated by co-operation often fails to be executed successfully, because it was generated without capacities of suppliers and more over nested suppliers. To overcome this limitation, the supply chain plan should be generated truly integrated way. In this paper, we classify business patterns based on scenarios, and present business process models about them. In addition, we describe the types of supply chain planning problem.